Seachem Prime vs API Stress Coat
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Here's how they compare by their makers' own pages. We haven't tested them.
Side by side
| Seachem Prime | API Stress Coat | |
|---|---|---|
| Chlorine and chloramine | Removes both | Removes both |
| Ammonia | Detoxifies (Seachem) | Not claimed |
| Nitrite and nitrate | Detoxifies (Seachem) | Not claimed |
| Heavy metals | Detoxifies at typical tap levels (listing) | Detoxifies (API) |
| Slime coat | Not claimed | Aloe vera; "replaces the natural secretion of slime" |
| Dose | 5 mL per 50 US gal | 5 mL per 10 gal; double to repair fins |
| During cycling | "Will not halt your cycling process" | "Does not affect the biological filter" |
| pH | "Will not impact pH" | Doesn't affect pH (API FAQ) |
The chloramine question
UF says chloramine "is a combination of chlorine and ammonia," and Seachem says breaking it leaves ammonia ("chloramine minus chlorine = ammonia"). API's page says tap water contains "chlorine, chloramines and ammonia," but only Prime claims to detoxify ammonia. Seachem says Prime binds those compounds "for up to 48 hours" until the filter's bacteria handle them.
Notes
- Seachem warns that Nessler-type ammonia kits won't read correctly with Prime; with salicylate kits, read right away. See test kits.
- Seachem allows a double dose for very high chloramine and up to 5x for emergency nitrite detox; use half dose above 86°F if chlorine or ammonia is low.
- API says Stress Coat isn't recommended with a protein skimmer (a saltwater item).
The picks
Seachem Prime (250 mL)
- Removes chlorine and chloramine, per the listing
- Detoxifies ammonia and nitrite at typical tap-water levels
- 5 mL treats 50 US gallons of new water
Seachem Prime (500 mL)
- Larger bottle of the same conditioner, per the listing
- 5 mL per 50 US gallons of new water
API Stress Coat (16 oz)
- Makes tap water safe, per the listing
- Aloe vera to help replace the slime coat
- 5 mL per 10 gallons; double dose for damaged fins
More in water conditioners.
FAQ
Main difference?
Prime claims ammonia detox; Stress Coat adds aloe.
More concentrated?
Prime: 5 mL per 50 gal vs 5 mL per 10 gal.
Stops cycling?
Neither, per the makers.