Seachem Prime (500 mL)
The benchmark conditioner: highly concentrated, full spectrum and overdose safe. One capful treats 50 gallons — it removes chlorine, neutralises chloramine and detoxifies ammonia and nitrite in a single dose.
- +Full spectrum — removes chlorine, neutralises chloramine and detoxifies ammonia and nitrite in one dose
- +Also binds heavy metals and gives nitrite protection while a tank cycles
- +Highly concentrated — one capful treats 50 gallons, so a 500 mL bottle lasts months
- +Overdose safe to about 5x, does not affect pH, and is shrimp safe and plant safe
- −Sulphurous smell, and the dosing cap is easy to over-pour
- −Its ammonia detox is temporary (about 24-48 hours), binding rather than removing it
This is Seachem Prime, a highly concentrated water conditioner. One 5 mL capful treats 50 gallons, so a 500 mL bottle treats roughly 5,000 gallons. In a single dose it removes chlorine, neutralises chloramine and temporarily detoxifies ammonia and nitrite, and it also binds heavy metals. It is overdose-safe to about five times the label dose, pH-neutral, and safe for shrimp, plants and the biofilter.
- Every water change on chlorinated or chloramine tap water
- Emergency ammonia or nitrite spikes, where it buys 24 to 48 hours
- Fishless cycling and new tanks that need nitrite protection
- Shrimp and planted tanks, since it is safe for both
- Anyone who dislikes measuring a tiny dose, since the cap over-pours easily
- Keepers expecting it to remove ammonia permanently, because it only binds it temporarily
- Anyone bothered by a sulphur smell, which is normal for the formula
We separate what the maker claims from what independent sources confirm, what owners report, and where we are drawing an inference. We do not bench-test products.
- Treats chlorine, chloramine, ammonia, nitrite and heavy metals
- 5 mL per 50 gallons
- Overdose tolerance around five times the label dose
- No pH impact; safe for shrimp, plants and the biofilter
- It is highly concentrated, one capful per 50 gallons
- Its ammonia and nitrite detox is temporary, roughly 24 to 48 hours
- It does not remove nitrate
- The benchmark conditioner across tens of thousands of reviews, praised for value and concentration
- Common gripes are the sulphur smell and how easily the cap over-pours
- The concentration makes it the cheapest conditioner per gallon over time
- The temporary ammonia detox is genuinely useful during a cycle or an emergency, but redose every 24 to 48 hours until the source is fixed
The cost per use is very low: a 500 mL bottle treats about 5,000 gallons, so a typical tank's water changes cost pennies and a bottle lasts months to years. There is no other consumable.
- Over-pouring from the cap, which is safe to about five times dose but wasteful, so use a syringe on nano tanks
- Assuming ammonia is gone permanently when it rebinds within 24 to 48 hours, so fix the root cause
- Confusing dosing to tank volume with dosing to water-change volume
- A very old bottle slowly losing potency
We do not lab-test the chemistry; we relay Seachem's stated figures and the well-known temporary-detox caveat. For a sick tank or a serious ammonia emergency, consult a veterinarian or an established authority alongside conditioning the water.
One 5 mL capful treats 50 gallons. Dose to the volume of new water on a water change, or to the whole tank volume in an ammonia emergency.
No. It detoxifies ammonia and nitrite temporarily, roughly 24 to 48 hours. Redose until your biofilter or water source resolves the cause.
It tolerates about five times the label dose, which makes it forgiving, but measure with a syringe on small tanks to avoid waste.
That odour is normal for the formulation and does not mean the bottle has gone bad.