Seachem Prime Water Conditioner, 250 ml

This bottle’s built for serious water prep—removes chlorine, chloramine, detoxifies ammonia and nitrite, and supports biofilter health. Geared toward freshwater and marine tanks, whether you’re doing full water changes or topping up. One capful treats 200L, so the 500ml bottle lasts ages. Works well in van stash, fish rooms, or home aquariums where water quality needs to stay tight. No smell, no clouding, and safe for all species. Ideal for new setups, emergency spikes, or routine maintenance. Can be used alongside meds and other treatments without clashing. Best dosed with a syringe or pipette for accuracy—cap measurements are rough. 👍 Pros ✅ Highly concentrated—small dose, big coverage ✅ Detoxifies ammonia and nitrite—supports cycling ✅ Safe for all fish, inverts, and plants ✅ No smell or residue—clean dosing ✅ Long shelf life—stays potent 👎 Cons ❌ Cap dosing is vague—use a syringe for precision ❌ No colour indicator—can’t see it in water ❌ Not a full-on bacteria booster—use with bio support if needed

Always use this product with other seachem products. One of the best and cheaper on amazon than I have seen. Generally I use after a water change. I use with clarity and the water quality is at its best when used. Very effective in keeping water quality and cost effective buying bigger bottles. Works quickly so I know my aquarium and fish are safe.

Great product at a great price

It doesn't just remove chlorine; it actually 'binds' ammonia and nitrite into a non-toxic form for up to 48 hours. This was a total lifesaver for me during a mini-cycle. It’s a five-star, high-quality product that gives you proper peace of mind every time you do a water change. Plus, it helps the fish produce their own natural slime coat rather than just adding a fake oily one. Brilliant stuff!

Very good product. Does exactly what it’s supposed to.

I've been using Seachem Prime Water Conditioner for years. One of the things I appreciate most about Seachem Prime is that it's very concentrated. I only need to use a small amount of the conditioner to treat my entire tank, which means that a single bottle lasts for a long time. This is particularly important for me, as I have a large tank and was previously using a less concentrated water conditioner that required me to use more of the product. Another great thing about Seachem Prime is that it's very easy to use. I simply add the recommended amount of conditioner to my tank each time I do a water change, and it does the rest of the work. Seachem Prime also has the added benefit of not affecting the pH level of my tank. This is particularly important for me, as I have a delicate ecosystem in my tank that requires a consistent pH level. I've found that some other water conditioners can cause fluctuations in pH levels, which can be harmful to my fish and plants. With Seachem Prime, I don't have to worry about this issue. Overall, I would definitely recommend Seachem Prime Water Conditioner to any fish owner looking for an effective and concentrated water conditioner. It does a great job of detoxifying tap water and keeping my fish healthy, without affecting the pH level of my tank. Plus, the concentrated formula means that a single bottle will last for a long time, making it a great value for the price.

I discovered yesterday, much to my horror, that my nitrite levels had spiked to around 4 - 5ppm - this is a toxic level for fish, my nitrate levels were up at around 50 (again not good news). I was gutted as I love the fish. I think the fault was not cycling the tank properly before I put my fish in and a few days after I bought my fish I changed my old and very used filter sponge for a brand new one - convinced I was doing my little fishies a lot of good! Yesterday afternoon, upon reading the results of my water test, I immediately did a 50 per cent water change and ordered this Seachem Prime as it had many reviews saying it immediately got rid of nitrites, nitrates and ammonia etc This morning when I woke up I did another 25 per cent water change and an hour later tested my water - I had managed to get my nitrite levels down to roughly 2ppm. This is still no good, they MUST read 0 or your fish are in danger. The Seachem Prime arrived today (less than 24 hours after ordering) and I immediately put 3ml into my 60L tank, which is 3x the stated dose but I had a nitrite emergency and felt happy all would be well. I read my water levels an hour later and the nitrite readings are now roughly 0 - 0.5. It has clearly had an immediate effect on these levels and probably saved my little fish. I also have 3 minuscule little fry in the tank and I am hoping it has saved their little lives as well. The nitrate levels are now at around 20 ish which is perfectly safe for fish. I am planning to put around 1ml of Prime into my water every 24 hours now, and do a 25 per cent water change twice a week until I think my tank has cycled fully. I will then reduce the Prime to once every 48 hours and continue to test, then once every 3 to 4 days and test to ensure there are no spikes and that my tank is cycled! I am so grateful for this product, I did not sleep a wink last night desperate to sort this problem out! Just to note, Seachem Prime can be used as a water conditioner by itself and it makes tap water safe for fish. However because this product had not arrived when I did my water changes I used API Stress Coat Plus in my new water which also makes tap water safe for fish as it removes chlorines and chloramines etc The Prime can be used in conjunction with other products, it will not harm the fish. In future when I do water changes I will use Prime only as my water conditioner. I also use a Gravel Cleaner liquid which breaks down waste and slows the build up of green algea. I cannot recommend this product enough if you have a nitrite spike, it will save fishy lives! UPDATE: LESS THAN 5 DAYS AFTER STARTING WITH THIS PRODUCT NITRITE AND NITRATE LEVELS BOTH 0. This is a great product. I'll now only use it as a water conditioner with my weekly water change!

Works well , I have a large cold water aquarium