★ SOSA reed diffusers · static oil level
Oil that stays put is usually a bottle that has stopped working, not a bottle that is being economical
★ ★ ★ ★ ★
★★★★★
"I was quietly pleased the level had not moved in a month. Then I lifted a reed and the wet line was right at the top. Two flips later the flat smelled of jasmine again."
Garden Bloom 50ml
★★★★★
"Thirty-second check, exactly as described. My wet line was barely above the oil, which meant the reeds had gone, not the fragrance."
Mountain Breeze 130ml
★★★★★
"Turned out nothing was wrong at all — sealed AC bedroom, door shut all day. Opening it in the mornings changed everything."
Evening Calm 50ml
★★★★★
"I had been treating a static level as proof of value for money. It was proof of a stalled bottle. Slightly humbling."
Fresh Brew 130ml
★★★★★
"Three states, and mine was the third. My mother walked in and said the house smelled lovely, so it was my nose all along."
Morning Freshness 50ml
★★★★★
"The line about the level not being the meter reading stuck with me. I mark the glass with tape now and check monthly instead of daily."
Fresh & Grounded duo ₹1,548
★★★★★
"I was quietly pleased the level had not moved in a month. Then I lifted a reed and the wet line was right at the top. Two flips later the flat smelled of jasmine again."
Garden Bloom 50ml
★★★★★
"Thirty-second check, exactly as described. My wet line was barely above the oil, which meant the reeds had gone, not the fragrance."
Mountain Breeze 130ml
★★★★★
"Turned out nothing was wrong at all — sealed AC bedroom, door shut all day. Opening it in the mornings changed everything."
Evening Calm 50ml
★★★★★
"I had been treating a static level as proof of value for money. It was proof of a stalled bottle. Slightly humbling."
Fresh Brew 130ml
★★★★★
"Three states, and mine was the third. My mother walked in and said the house smelled lovely, so it was my nose all along."
Morning Freshness 50ml
★★★★★
"The line about the level not being the meter reading stuck with me. I mark the glass with tape now and check monthly instead of daily."
Fresh & Grounded duo ₹1,548
✓ Six fibre reeds per bottle · fibre, not rattan, because rattan clogs in Indian humidity ✓ 50ml lasts 6–8 weeks · 130ml lasts 14–18 weeks · flip weekly, gloves on ✓ Alcohol-free, phthalate-free CCT base · composed and handmade in Pune
Founder Diaries · Reed Diffusers · Static oil level
State two — undersupplied: the reeds have stopped drawing. The wet line sits barely above the oil after the first fortnight. Add reeds or refresh them, and top the bottle to the neck.
State three — genuinely slow: a cold, sealed, low-traffic room really does evaporate less. Wet line normal, reed smells strong held close, a visitor notices the scent. Nothing is broken.
The thing nobody says out loud: the level is a slow, blunt instrument. A 50ml over its stated 6–8 weeks loses roughly a millilitre a day, which is invisible against curved glass on any given morning.
Oil refill₹2,399 · 300mlThe opposite failure, and the one people misread most often. Here the wet line has barely risen — after the first couple of weeks it still sits close to the oil surface, and most of the reed is dry to the touch. Nothing is reaching the air because nothing is reaching the top. Three causes, all free to check: too few reeds standing in the bottle, so total wicking capacity is low; too little immersion, because the level has dropped and only a short stub of each reed is submerged; or reeds that have simply aged past their useful life and are no longer drawing the way fresh fibre does. Fibre reeds hold up far better than rattan in Indian humidity — that is precisely why we use them — but they are still the consumable part of the system, and SOSA guidance is to refresh them every few months.
Oil refill · top to the neck₹2,399Shop → 
Mountain Breeze · 9.4/10from ₹849Shop → 
Sukoon · scent on demand₹1,899Shop →
SOSA reed diffuser range & prices (verified August 2026): alcohol-free, phthalate-free, paraben-free and IFRA-compliant compositions on a heat-stable coconut-derived (CCT) carrier, low-VOC, supplied in a refillable glass bottle with six fibre reeds; 50ml lasts 6–8 weeks and 130ml lasts 14–18 weeks. Morning Freshness (Malabar lemon · peppermint · Nilgiri eucalyptus) 50ml ₹749 · 130ml ₹1,249 · 9.0/10; Garden Bloom (British rose · night-blooming jasmine) 50ml ₹799 · 130ml ₹1,299 · 8.9/10; Evening Calm (Kashmir lavender · chamomile) 50ml ₹799 · 130ml ₹1,299 · 8.9/10; Fresh Brew (Coorg coffee · Kerala vanilla) 50ml ₹849 · 130ml ₹1,349 · 9.5/10; Mountain Breeze (Himalayan pine · sage · Indian cedar) 50ml ₹849 · 130ml ₹1,349 · 9.4/10. Reed diffuser refills are oil only — you reuse your own vessel and reeds: 300ml ₹2,399 (roughly 8–11 months) · 500ml ₹3,499 (roughly 14–18 months), about ₹7–8 per ml against ₹15–17 per ml for a 50ml bottle. Duo sets ₹1,498–₹1,598 for 2 × 50ml and ₹2,498–₹2,598 for 2 × 130ml. Strength figures are positions on SOSA’s own internal strength scale, not an industry standard. Replacement reeds are not sold as a separate SKU; SOSA guidance is to refresh reeds every few months. The reed line is separate from the water-based Hotel Collection for ultrasonic machines (15ml ₹299 · 100ml ₹999 · 300ml ₹1,799) and the two are not interchangeable. Diffusers: Boond 300ml ₹899 · Sukoon 500ml ₹1,899 · Megh 6L ₹3,499 · waterless Vaayu ₹11,999. Composed and handmade in small batches in Pune, India; tested through 45°C summer heat and 85% monsoon humidity. Free shipping above ₹499. A portion of every order supports girl-child education through Nanhi Kali. Prices subject to change — see the live product pages.
Most people who write to me about a level that has not moved in weeks write in a tone of mild pride, as though they have discovered an unusually economical bottle. Almost always they have discovered a stalled one. Oil in the glass is not fragrance in the room; it is fragrance that has not left yet, and a level that refuses to fall is telling you that the transport system between the two has quietly stopped. There are exactly three states a static level can mean, one of them is genuinely fine, and you can work out which one you are in before your tea gets cold.
Quick answers — read this first
State one — stalled: the reeds are saturated and no longer moving oil. Lift a reed: the wet line sits high and the reed looks dark and heavy. Flip all six. Free.State two — undersupplied: the reeds have stopped drawing. The wet line sits barely above the oil after the first fortnight. Add reeds or refresh them, and top the bottle to the neck.
State three — genuinely slow: a cold, sealed, low-traffic room really does evaporate less. Wet line normal, reed smells strong held close, a visitor notices the scent. Nothing is broken.
The thing nobody says out loud: the level is a slow, blunt instrument. A 50ml over its stated 6–8 weeks loses roughly a millilitre a day, which is invisible against curved glass on any given morning.
The short answer
Short answer: your reed diffuser's oil is not going down because it has stopped delivering, not because it is being frugal. Lift one reed out and find the boundary between the oil-soaked part and the dry part — the wet line. High and dark means saturated and stalled: flip all six reeds and it will come back within a day. Barely above the oil means the reeds are not wicking: add reeds or replace them. Normal wet line, quiet room, everything else in order: you are probably adapted to a scent that is working perfectly well.
The mechanism: oil climbs a fibre reed by capillary action and leaves from the exposed end. Those two halves must both be running. If the exposed end has silted up with the heavy, low-volatility part of the composition, evaporation slows to nearly nothing and the level freezes — the bottle looks full because the fragrance is trapped in the glass, not because it is being conserved.
Shop: nothing on this page needs a purchase to fix. If a flip and a re-place both fail, the honest answer is fresh reeds and a top-up of oil — the 300ml refill is ₹2,399 and runs a vessel roughly 8–11 months. New bottles start at ₹749 for Morning Freshness 50ml. Free shipping above ₹499.
In this guide
If the room needs more presence
Mountain Breeze 9.4 · from ₹849
If the bottle needs topping up
300ml oil refill · ₹2,399
If you want scent on demand
Sukoon ultrasonic · ₹1,899
Straight answer
My reed diffuser oil has not gone down in weeks. What does that mean?
1. Run the wet-line test before anything else. Pull one reed out with gloves on and hold it up. Somewhere along its length there is a boundary between the darkened, oil-soaked portion and the pale dry portion. That boundary is the single most informative thing about your diffuser, and it takes ten seconds to read.
2. Wet line high and the reed dark — you are stalled. The reed is full to the top and delivering nothing, because the exposed end has accumulated the heavy fraction of the composition and sealed itself. Flip all six reeds, put them back, and judge the room the following evening rather than the following minute.
3. Wet line barely above the oil after week two — you are undersupplied. The reeds are not drawing. Either there are too few of them, or the oil has fallen below a useful immersion depth, or the reeds are simply old. Top the bottle to the neck and add or refresh reeds.
4. Wet line normal and everything else in order — you are probably fine. Hold a reed a few inches from your nose. If it smells clearly of the composition, oil is moving. A cold, sealed, still room genuinely evaporates less, and your own nose is the least reliable witness in the house.
5. Do not buy a bigger bottle to fix a static level. More oil behind a stalled reed is more oil sitting still. Size buys duration, never projection, and a 130ml with saturated reeds is exactly as quiet as a 50ml with saturated reeds.
6. Do not top up on top of old reeds and call it solved. Reeds are the consumable in this system; the oil is the stable part. People replace the oil and keep the reeds, and it is almost always the other way round.
Composed and handmade in small batches in Pune, and a portion of every order supports girl-child education through Nanhi Kali.
2. Wet line high and the reed dark — you are stalled. The reed is full to the top and delivering nothing, because the exposed end has accumulated the heavy fraction of the composition and sealed itself. Flip all six reeds, put them back, and judge the room the following evening rather than the following minute.
3. Wet line barely above the oil after week two — you are undersupplied. The reeds are not drawing. Either there are too few of them, or the oil has fallen below a useful immersion depth, or the reeds are simply old. Top the bottle to the neck and add or refresh reeds.
4. Wet line normal and everything else in order — you are probably fine. Hold a reed a few inches from your nose. If it smells clearly of the composition, oil is moving. A cold, sealed, still room genuinely evaporates less, and your own nose is the least reliable witness in the house.
5. Do not buy a bigger bottle to fix a static level. More oil behind a stalled reed is more oil sitting still. Size buys duration, never projection, and a 130ml with saturated reeds is exactly as quiet as a 50ml with saturated reeds.
6. Do not top up on top of old reeds and call it solved. Reeds are the consumable in this system; the oil is the stable part. People replace the oil and keep the reeds, and it is almost always the other way round.
Composed and handmade in small batches in Pune, and a portion of every order supports girl-child education through Nanhi Kali.
TL;DR: a static level means stalled reeds, starved reeds, or a genuinely slow room — in that order of likelihood. Lift one reed, read the wet line, flip all six, and judge the next evening. Only after that does anything cost money.
The scent people most often report as "stopped"
SOSA Garden Bloom · British rose & night-blooming jasmine ₹799 / 50ml
Florals carry a heavier tail than citrus does, which means the exposed end of a reed silts up a little sooner and a missed flip shows up a little faster. Nothing is wrong with the bottle when that happens — it is the most flippable fragrance we make, in the sense that a flip returns the most. Rated 8.9 on our own internal scale at six reeds, built for entryways and living rooms, on the same alcohol-free, phthalate-free CCT base as the rest of the range. 130ml ₹1,299 for 14–18 weeks.
Part one — the three states a frozen level can mean
A reed diffuser is a two-stage machine with no moving parts: oil is lifted up the fibre by capillary action, and it leaves from the exposed end into the air. The level in the glass falls only when both stages are running. Stop either one and the level stops falling, which is why a static level on its own tells you almost nothing — it is the same reading for a bottle that has silted up, a bottle that has never got started, and a bottle behaving perfectly in a cold sealed room. The three cards below are the three states, in the order I would check them. Each one has a physical tell you can read in seconds, and none of the tells is your own nose in your own living room.
1
STATE ONE · MOST COMMON
Stalled — saturated at the top, delivering nothing
The reed is full. That is the problem. Over several weeks the exposed end collects the heaviest, least volatile part of the composition while the lighter molecules leave first, and what remains is a dense residue that both smells of very little and blocks the surface that fragrance would otherwise leave from. The wet line sits high on the reed, often within an inch or two of the top, and the reed looks darker and feels heavier than it did on day one. Evaporation drops to a trickle, the level freezes, and the owner concludes the bottle is being economical. It is not being economical; it is holding your fragrance hostage. Flip all six reeds with gloves on, stand them back in the bottle, and let the room have a full evening to respond. In state one, that alone usually settles it.
The tell: wet line high, reed dark, room quiet. If the reed itself smells muted when you hold it close, the residue has sealed the surface.
2
STATE TWO · THE UNDERSUPPLY
Starved — the oil is not climbing in the first place
Oil refill₹2,399 · 300mlThe opposite failure, and the one people misread most often. Here the wet line has barely risen — after the first couple of weeks it still sits close to the oil surface, and most of the reed is dry to the touch. Nothing is reaching the air because nothing is reaching the top. Three causes, all free to check: too few reeds standing in the bottle, so total wicking capacity is low; too little immersion, because the level has dropped and only a short stub of each reed is submerged; or reeds that have simply aged past their useful life and are no longer drawing the way fresh fibre does. Fibre reeds hold up far better than rattan in Indian humidity — that is precisely why we use them — but they are still the consumable part of the system, and SOSA guidance is to refresh them every few months.
The tell: wet line barely above the oil after week two, dry reed above it, and a flip that changes nothing by the next day.
3
STATE THREE · NOTHING IS WRONG
Genuinely slow — a cold, sealed, still room
Evaporation is a physical process and it responds to the room. In a cool, air-conditioned, closed bedroom with the door shut most of the day and very little foot traffic, a bottle really will lose oil more slowly than the same bottle on a hall console in a Chennai summer. In that case the wet line reads normally, the reed smells clearly of the composition when you hold it a few inches away, and a visitor who has just walked in from outside will tell you the room smells of lavender. Every one of those is a better instrument than the level in the glass, and better than your own nose, which stops reporting a constant background within minutes and adapts hardest at home. If all three read well, you do not have a fault — you have a slow room, and the fix, if you want one, is distribution rather than a purchase.
Part two — the thirty-second triage, in one table
This is the whole diagnostic on one screen. Take one reed out, read the two columns on the left, and the rest of the row tells you what you are looking at. The only equipment is a pair of gloves and a tray to stand things on, because reed oil marks wood and stone.
Read one reed, read the row
The three states, side by side
| What the wet line does | How the reed looks and feels | Held close, the reed smells | The state you are in | Your first move |
|---|---|---|---|---|
| Sits high — near the top of the reed ★ | Dark, heavy, slightly tacky | Muted, thick, not much like the bottle | Stalled and saturated | Flip all six · free · judge tomorrow evening |
| Barely above the oil after week two | Pale and dry along most of its length | Faint — there is little oil up there to smell | Starved of supply | Top to the neck, add or refresh reeds |
| Steady around the middle, moving slowly | Evenly tinted, flexible, not tacky | Clearly of the composition | Working — the room is simply slow | Change placement and airflow, buy nothing |
| High on some reeds, low on others | Mixed — usually the older reeds are darker | Uneven from reed to reed | Part-flipped, or reeds of different ages | Flip all of them, every time, not a few |
| Falling fast, bottle emptying early | Dry-looking despite a falling level | Strong at the bottle, absent across the room | Draught or direct sun stripping the reeds | Move away from the vent, fan or window |
| The honest caveat: the wet line is a diagnostic, not a measurement. It tells you which of the three states you are in; it does not tell you how many weeks the bottle has left, and it will read differently on a 130ml simply because there is more depth of oil beneath it. Read it as a signal, run the free fixes, and give the room a full evening before deciding anything. | ||||
Shop this guide
What each of the three states actually needs
Oil refill · top to the neck₹2,399Shop → Mountain Breeze · 9.4/10from ₹849Shop → Sukoon · scent on demand₹1,899Shop →
The SOSA principle
Oil left in the glass is not money saved. It is fragrance that never arrived.
The only reason to be pleased about a slow-moving level is if the room smells the way you want it to at the same time. Longevity without output is not thrift; it is a stalled bottle wearing thrift's clothes.
Part three — why the oil level is such a poor instrument
Even when everything is working, the level is close to unreadable in the short term. Take the stated window for a 50ml — six to eight weeks — and do the arithmetic: that is somewhere around a millilitre a day, spread across a curved glass base. On any given morning the difference between a working bottle and a stalled one is smaller than the meniscus you are squinting at. People check daily, see nothing, and draw a conclusion that the instrument was never precise enough to support. The 130ml is worse in this respect, not better, because the same daily loss is spread across a wider column of oil and takes fourteen to eighteen weeks to visibly resolve. This is why I ask people to stop using the level as their primary check and start using the reed.
There is also a shape problem. Most reed bottles, ours included, are not straight-sided cylinders; they narrow towards the neck, which means the same millilitre lost produces a visibly different drop depending on where in the bottle you are. Early on, when the oil sits in the wide part of the glass, weeks can pass with the level looking almost identical. Later, in the narrow section, the same rate of loss looks alarming and people write to ask why it has suddenly accelerated. Nothing has accelerated. The geometry changed, not the physics. If you genuinely want to track it, put a strip of masking tape on the glass on the day you set the bottle up, mark the line, and look again in a month — not tomorrow.
And there is the deeper point, the one this whole sub-cluster of articles exists to make: the level measures what has left the bottle, not what has arrived in the room. Those are different quantities, and they come apart in both directions. A bottle in a direct draught from a split AC will empty weeks early while the room smells of very little, because the fragrance is being stripped off the reeds and flushed away before it can distribute. A bottle in dead air behind a sofa will hold its level beautifully and also do nothing, because there is no air exchange to carry anything. Neither of those is a fault in the oil. Both are read correctly in about a minute by lifting a reed, holding it close, and then asking someone who has just walked in whether the room smells of anything.
A bottle that never goes down is not saving you money. It is quietly refusing to do its job.
— Sonal Sahani, SOSA
Part four — what to do, in order, and what each step costs
The ladder below runs from free to paid, and most people never get past the third rung. I would rather you spent nothing and had a working diffuser than spent ₹1,349 on a bigger bottle that stalls in the same corner of the same room.
The static-level ladder
Free fixes first, purchases last
| Order | The move | What it costs | When to move on to the next rung |
|---|---|---|---|
| 1 ★ | Lift one reed and read the wet line | Thirty seconds and a pair of gloves | Immediately — this only tells you where to go next |
| 2 | Flip all six reeds, not three of them | Free · two minutes | If the room is unchanged by the following evening |
| 3 | Move the bottle into gentle passing air, waist to chest height, away from vents and sun | Free · and it often lengthens the bottle | After a couple of days in the new spot |
| 4 | Ask a visitor, or close the room for an hour and come back in | Free · costs you an hour | If they smell it and you do not, stop here — it is adaptation |
| 5 | Add two to four reeds | Free, but shortens the bottle roughly in proportion | If projection rises but not enough |
| 6 | Refresh the reeds and top the oil to the neck — 300ml refill | ₹2,399, about ₹7–8 per ml against ₹15–17 for a 50ml bottle | Only once flipping has clearly stopped returning anything |
| 7 | Change the composition — Fresh Brew 9.5 or Mountain Breeze 9.4 | From ₹849 · 50ml | When the room is right and you simply want more presence |
| Never | Buy a 130ml to cure a static level | From ₹1,249 — and it will stall in exactly the same way | Buy the larger size for 14–18 weeks of duration, not for volume |
Honest notes for buyers: the wet-line readings on this page are SOSA working guidance drawn from in-house testing and years of customer correspondence, not laboratory measurement — reeds differ, rooms differ, and seasons differ. Strength figures such as 9.5 or 8.9 are positions on SOSA's own internal scale at six reeds, not an industry standard and not a concentration. Our refills are oil only: you reuse your own glass vessel and your own reeds, and replacement reeds are not sold as a separate item — that is a real gap in our range and we would rather say so than pretend otherwise. Reed oil never goes into a Sukoon or Boond, and the water-based Hotel Collection never goes into a reed bottle. Stand the bottle on a tray, keep it out of direct sunlight, and keep it away from children and pets. Composed and handmade in small batches in Pune, and a portion of every order supports girl-child education through Nanhi Kali.
When the diagnosis is "working, but too quiet for this room"
SOSA Mountain Breeze · Himalayan pine, sage & Indian cedar ₹849 / 50ml
If the wet line reads normally, a flip changes little because nothing was wrong, and a visitor confirms the room does smell — but of less than you wanted — then you have a composition question rather than a fault. Mountain Breeze sits at 9.4 on our internal scale at six reeds and is the highest-projecting thing we make with no sweetness in it at all. Dry, resinous and steady, on a heat-stable CCT base tested through 45°C summers and 85% monsoon humidity. 130ml ₹1,349 for 14–18 weeks.
SS
ISIPCA
Versailles
Versailles
A note from Sonal
There is a particular email I get perhaps twice a week, and it always begins the same way: I bought your 50ml in March and it is August and the bottle is still nearly full — is that normal? The writer expects me to be pleased. What I feel instead is a small sinking, because I know what has almost certainly happened: the reeds have not been flipped, the exposed ends have silted up with the heavy end of the composition, and five months of fragrance that somebody paid for is still sitting in the glass.
I want to be honest about our part in that. We publish a 6–8 week figure for the 50ml and a 14–18 week figure for the 130ml, and those numbers assume weekly flipping, six reeds, an ordinary room and no draught. When a bottle outlives its window by months, the first thing I check is not whether the customer got lucky. It is whether the system stopped.
The fix costs nothing and takes two minutes, which is why this article exists rather than a product page. Lift a reed, look at the wet line, flip all six, wait an evening. If you want the composition to do more than that, the levers are reed count, placement and choosing something built louder — and if what you want is a strong room on demand, a Sukoon at ₹1,899 is a better tool than any reed bottle, including mine. Everything we make is composed and handmade in Pune, and part of every order funds a girl's classroom through Nanhi Kali.
Frequently asked questions
Is it good if my reed diffuser oil is not going down?
Only if the room still smells of it. Oil in the glass is fragrance that has not been delivered, so a static level with a quiet room means the bottle has stalled, not that it is being economical. The exception is a cold, sealed, low-traffic room, where slower evaporation is genuine — but even then the reed should smell clearly of the composition when you hold it close.
How do I tell whether the reeds are saturated or just not wicking?
The wet line. Lift one reed and find the boundary between the darkened, oil-soaked part and the dry part. High on the reed and looking dark means saturated and stalled — flip all six. Barely above the oil after the first fortnight means the reeds are not drawing — add reeds, refresh them, and top the bottle to the neck.
How quickly should the level drop on a 50ml bottle?
Across a stated 6–8 week life that works out at roughly a millilitre a day, which is essentially invisible on any single morning and only becomes obvious after several weeks. That is why the level is a poor daily check. If you want to track it, mark the glass with tape on day one and look again in a month.
Should I add oil to a bottle that is still full?
No — a full bottle is not short of oil, it is short of delivery. Adding more to a stalled system changes nothing. Flip first, move the bottle into passing air, and only reach for the refill when you are also putting in fresh reeds, since reeds are the part that wears out.
Will a 130ml solve this?
No. A 130ml holds more oil and therefore lasts 14–18 weeks against 6–8, but at the same six reeds it projects the same. If your 50ml has stalled, the 130ml will stall identically and you will simply have more oil sitting still. Buy the larger size when you want fewer repurchases, not when you want a louder room.
Static oil level · 2027
Lift one reed. Read the wet line. Then flip all six and judge the room tomorrow, not tonight
Every SOSA reed diffuser ships with six fibre reeds on an alcohol-free, phthalate-free CCT base — 50ml from ₹749 for 6–8 weeks, 130ml from ₹1,249 for 14–18 weeks. When the reeds have genuinely run their course, the oil-only refill is ₹2,399 for 300ml at roughly half the per-millilitre price of a new bottle. Free shipping above ₹499, and a portion of every order supports girl-child education through Nanhi Kali.
Shop reed diffusers → Refill from ₹2,399
Continue the read
More on a bottle that lasts but does not smell
- Lasting a long time but giving very little fragrance — why those two facts are the same fact.
- Barely evaporating? — the cold, sealed, still room, and when nothing is actually wrong.
- Reeds not absorbing enough oil and does slow evaporation mean it is broken?
- The complete guide to a diffuser that lasts too long, and why can't I smell my reed diffuser?
- Brand: the SOSA founder story.
Editorial standards & sources
About this guide: Written by Sonal Sahani, ISIPCA Versailles-trained founder and perfumer at SOSA Home & Body, on what a reed diffuser's oil level does and does not tell you. The wet-line readings, the three-state triage and the "roughly a millilitre a day" figure are SOSA working guidance interpolated from our published 6–8 week and 14–18 week bottle lives and from in-house testing and customer correspondence — they are not laboratory measurements, and real results vary with room volume, ceiling height, ventilation, traffic and season. Strength ratings are positions on SOSA's internal scale at six reeds, not an industry standard.SOSA reed diffuser range & prices (verified August 2026): alcohol-free, phthalate-free, paraben-free and IFRA-compliant compositions on a heat-stable coconut-derived (CCT) carrier, low-VOC, supplied in a refillable glass bottle with six fibre reeds; 50ml lasts 6–8 weeks and 130ml lasts 14–18 weeks. Morning Freshness (Malabar lemon · peppermint · Nilgiri eucalyptus) 50ml ₹749 · 130ml ₹1,249 · 9.0/10; Garden Bloom (British rose · night-blooming jasmine) 50ml ₹799 · 130ml ₹1,299 · 8.9/10; Evening Calm (Kashmir lavender · chamomile) 50ml ₹799 · 130ml ₹1,299 · 8.9/10; Fresh Brew (Coorg coffee · Kerala vanilla) 50ml ₹849 · 130ml ₹1,349 · 9.5/10; Mountain Breeze (Himalayan pine · sage · Indian cedar) 50ml ₹849 · 130ml ₹1,349 · 9.4/10. Reed diffuser refills are oil only — you reuse your own vessel and reeds: 300ml ₹2,399 (roughly 8–11 months) · 500ml ₹3,499 (roughly 14–18 months), about ₹7–8 per ml against ₹15–17 per ml for a 50ml bottle. Duo sets ₹1,498–₹1,598 for 2 × 50ml and ₹2,498–₹2,598 for 2 × 130ml. Strength figures are positions on SOSA’s own internal strength scale, not an industry standard. Replacement reeds are not sold as a separate SKU; SOSA guidance is to refresh reeds every few months. The reed line is separate from the water-based Hotel Collection for ultrasonic machines (15ml ₹299 · 100ml ₹999 · 300ml ₹1,799) and the two are not interchangeable. Diffusers: Boond 300ml ₹899 · Sukoon 500ml ₹1,899 · Megh 6L ₹3,499 · waterless Vaayu ₹11,999. Composed and handmade in small batches in Pune, India; tested through 45°C summer heat and 85% monsoon humidity. Free shipping above ₹499. A portion of every order supports girl-child education through Nanhi Kali. Prices subject to change — see the live product pages.