Seachem Purigen Freshwater, 250 ml

Use this in all my filters in my heavily overstocked tanks as part of my quest to always have perfect water clarity. I have 3 or 4 filters depending on the size of my tank mainly because I do overstock them but together with my cleaning routine and using this product my water in my tanks are spotless. If i turn the filters off before feeding my fish look like they are just floating in air and visitors often comment on how clear my water is. Despite being overstocked my fish appear healthy and are long living and I put this down to several things including the effectivebess of using this product. A little goes a long way so in my mind at least I think this Seachem product is good value for money and I wouldn't be without it.

Seachem Purigen – my “HD water” upgrade for crystal‑clear tanks Purigen is the product I reach for when I want that next level of polish. It consistently strips out the dissolved organics that make water look tired—tannins, slight yellowing, and odours—without flattening the life out of a planted or community tank. The end result is that crisp, glassy clarity that makes colours pop and hardscape look like it’s floating. What I notice in real use Immediate visual lift: Within days the water shifts from “clean” to sparkling, with noticeably better light penetration and contrast. Less film and odour: Surface sheen and any faint musty smell are dialled right down. Stable chemistry: It targets dissolved organics rather than stripping essential minerals; I’ve not seen it upset parameters when used as directed. Where it fits in the filter Pop Purigen in a fine media bag and place it towards the end of the flow path, after mechanical (sponges/floss) and bio (e.g., ceramic/Matrix) stages. Clean water hitting Purigen = better contact time and longer life. Don’t pack it too tightly—let water flow through rather than around it. Maintenance & regeneration (simple and cost‑effective) It changes colour from off‑white to dark brown/black as it’s exhausted. That’s your cue to recharge. Follow the label: bleach‑soak to regenerate, then thoroughly neutralise with a dechlorinator and rinse before returning it to the tank. (Pause UV/ozone during this step and never mix bleach with any other chemicals.) Because it’s reusable for multiple cycles, it’s great value, especially if you run several aquariums. Tips from day‑to‑day use Pair it with solid mechanical pre‑filtration; the less gunk hitting Purigen, the longer it lasts. If you want a mild tannin tint (e.g., for a blackwater look), use a smaller pouch or remove Purigen after the water looks how you like it. It works across canisters, HOBs, internals, and sumps—just keep it in a tight, fine bag so granules don’t escape. Verdict If biological media is the engine of your filtration, Purigen is the finishing filter that gives you that “show tank” shine. It’s my go‑to for high‑definition water, fast cosmetic improvements, and long‑term polish without constant replacements. For me, it’s a simple, reliable upgrade that makes every aquarium look its best.

I'm stunned by how quickly this stuff cleared both of my fishtanks, but the smaller one in particular was the worst - I placed a new piece of bogwood in it after having left it outside for 6 months in a drum of water all throughout the winter last year. I put it in my tank not expecting the water to discolour much & was horrified to see it turn brown after six days!! Then I read about this stuff and gave it a go...am I glad I did too, cuz it cleared it completely overnight & now it's crystal clear - I'd highly recommend it to anyone who's desperate to clear their fishtank or any aquatic water for that matter! It's worth every penny imho & it's reusable.....brilliant

Dropped this into a 120L planted tank running a canister filter—water went from tea-stained to glass-clear in under 48 hours. It targets dissolved organics, not just visible muck, so it’s ideal for setups with driftwood, heavy feeding, or cloudy water issues. Comes pre-packed in a mesh pouch—no measuring, no mess. Just rinse, drop into your filter tray or media basket, and let it work. I’ve used it in both RTA-style filters and hang-ons—no flow restriction, no breakdown. 🔍 Specs & Features Size: 100ml pouch (treats up to ~400L depending on bioload) Type: Synthetic polymer resin Use: Freshwater only (this version) Function: Removes tannins, ammonia, nitrites, nitrates, and dissolved organics Regeneration: Can be cleaned and reused with bleach (instructions provided) 🧪 Performance Clarity: Noticeable improvement in 24–48 hours Smell: Reduces tank odour Colour: Clears brown tint from driftwood setups Longevity: Lasts 4–6 weeks depending on load Reusability: Can be regenerated multiple times—saves cost long-term 👍 Pros ✅ Clears water fast—removes organics and tannins ✅ Pre-packed—no mess, no measuring ✅ Reusable—regenerates with bleach ✅ No impact on pH or hardness ✅ Works in most filter types 👎 Cons ❌ Needs bleach for regeneration—follow safety steps ❌ Doesn’t remove heavy metals or meds ❌ Can clog if used in very dirty tanks—pre-filter recommended ❌ Not a substitute for water changes 🧭 Personal Verdict If you want crystal-clear water without chemical dosing or constant maintenance, Purigen earns its spot. I’ve used it in planted tanks, fry setups, and even shrimp tanks—no drama, just clean results. It’s proper gear for anyone who wants clarity without compromise.

It works brilliantly. Never had any water chemistry issues (or any tannins leech) when I used this in my aquariums, so long as I replaced it every so often or cleaned it out. Definitely worth the value for a clear tank

I just put it in my filter and my fish tank's water became cleaner as never it was. Really effective, you can se the result in an hour. The package size is great for a medium filter. I use it in a 60L tank. More than enough!

Ok so I recently had two problems one the filters that came with my rank were hopeless so I had to upgrade to a Fluval 406 which is great by the way. I tried to use as much of the older filter media as possible but fully expected a mini cycle and an ammonia spike due to the change. For the last week I had also been plagued by slightly cloudy water more noticeable when viewing the tank lengthways but still annoying ! So in went the Fluval about three days later in that went the Purigen. Readings taken before the Purigen showed a slight ammonia spike at .25 and nitrites also high and nitrates at about 40 so basically not good! 24 hours after the Purigen went in these were at 0! The other thing as you will see is it has visibly cleared the slight cloudiness after 48 hours this is almost completely crystal clear even when the tank is viewed length way so it works! Apart from this it has also done something which I don't really know how to describe but everything just looks more vibrant it's like I went from standard definition to HD. I think cost wise it's reasonable. Especially when compared to say Chemi Pure which to treat my tank would cost close to 40 pounds with one pouch if Purigen is actually more than enough for my 300 litre tank. I am still running normal carbon as this extends the life of the Purigen and also Purigen fits easily into my Fluval 406. Now for the caution bit. I was actually considering taking one star off for this because I don't think Seachem make this clear enough unless you do your own research which I did but many don't ! Once finding numerous threads on the internet about two serious issues I wrote to Seachem who have clarified and confirmed so this is straight from Seachem. Issue no 1 . Many water conditioners that are used today in water changes contain a slime coat element which contains amines. This could render the Purigen useless. To be on the safe side you need to use a water conditioner which does not have this ingredient like Seachem Prime, or remove the Purigen from the filter during water changes for about 24 to 48 hours. To be clear using a water conditioner that contains amines won't create any toxicity but will reduce the effectiveness of it and also saturate it so it is not capable of being recharged. Issue number 2. If you use a water conditioner containing amines which many do, then if you use this to regenerate your Purigen it will make it toxic and kill your fish. It is hard to know whether or not a water conditioner contains amines one that is safe is Seachem Prime. Amines are not necessarily listed on the ingredients as there are variations of this chemical. I know that the Fluval and Tetra water conditioners are both not safe to regenerate Purigen. What happens if you try to regenerate your Purigen with one of these water conditioners is a chemical reaction which will trigger highly toxic chloramine in your tank. As I do not intend to reuse or regenerate my Pugin this is not a problem for me but I have switched to using a different water conditioner just to be on the safe side. I really do think that Seachem should make this clear to people purchasing this product as the consequences could be catastrophic. I will continue to use this product as it seems to really help with water clarity and chemistry but I will be purchasing a new bag when this one runs out. I suggest if you do want to use this product switch to Seachems water conditions also either Prime or Safe to get the most out of it.

I had slightly green tinge to my tank I couldn’t seem to clear and I read about this product and thought I’d give it a try. Within 24 hours my tank water is crystal clear and it’s like looking at a HD screen. Would 100% recommend.

works like magic i have used it for like 2 years now in 2026, i have a bio load of 6 fish in a 60 litre setup with canister filter, ran one pack of 100ml for 9 months straight and tille the last day the water was like crystal clear like as it was on day 1, definately go for it if want crystal clear water in your tank, and one thing, in these 2 years no dead fish in my tank just one death and that was due to jumping out of the tank at night 🤣

As expected

Muito bom

Es un excelente 👌 producto para el filtro de tu pecera además es una resina reciclable de manejara muy fácil

after putting the purigen, can noticeably see the clarity of the water. very satisfied with the addition of this chemical filter.