Seachem Prime (500 mL)
$16.62
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.
Pros
- 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
Cons
- 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
Score breakdown
Specifications
| Treats | Chlorine, chloramine, ammonia, nitrite, heavy metals |
|---|---|
| Contact Time | Works within minutes |
| Formulation | Concentrated liquid |
| Concentration | 5 mL per 50 gal |
| Treats Volume | ~5,000 gal per 500 mL |
| Bottle Size | 500 mL |
| Safe For | Shrimp, plants, biofilter |
| Overdose Tolerance | ~5x label dose |
| pH Impact | None |
Alternatives
$8.48 · 94 / 100A+
The cheapest effective dechlorinator: 1 mL treats 20 gallons. It removes chlorine, neutralises chloramine and binds heavy metals — but it does not detoxify ammonia, so keep a test kit handy while cycling.
$18.47 · 93 / 100A+
Powdered Prime for big tanks and fish rooms — the same full-spectrum chemistry in dry form, at the lowest cost per gallon in the hobby. Fiddly to dose in a small tank, unbeatable value in a large one.
$10.98 · 93 / 100A+
The dechlorinator that also heals: removes chlorine and neutralises chloramine while adding an aloe-vera slime coat that reduces stress and helps torn fins recover. Not an ammonia detoxifier.
Some links are affiliate links: if you buy through them we may earn a commission at no extra cost to you. It never changes our rankings. Full disclosure.