Seachem Flourish Comprehensive (500 mL)
The classic trace supplement — not a complete fertiliser. Flourish is micros and trace elements only, so it is best paired with a nitrogen phosphorus potassium source rather than run alone.
- +A rich blend of trace elements and micronutrients including chelated iron
- +Gentle and low phosphate, so it is balanced and shrimp safe with no algae bloom
- +Cheap, widely available, and a long-time hobby staple for topping up micros
- +Dilutable, with a measured cap for easy dosing on a light planted tank
- −Micros only — it lacks nitrogen and potassium, so plants in a lean tank still starve without a macro source
- −As a supplement it does little run alone; it assumes another fertiliser supplies the macros
This is Seachem Flourish Comprehensive, a trace-element and micronutrient supplement with chelated iron. Importantly it is NOT a complete fertiliser: it contains no nitrogen or potassium, so it is meant to top up micros alongside a separate macro source, not to run alone.
- Topping up trace elements and iron on a lightly planted tank
- Tanks that already get nitrogen and potassium from fish load or a macro dose
- Keepers who want a cheap, widely available micro supplement
- Use as a tank's only fertiliser, since it lacks macros
- Lean tanks where plants need nitrogen and potassium
- Anyone expecting a complete all-in-one, where Thrive fits
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.
- A full trace and micronutrient blend with chelated iron
- Very low phosphate; shrimp safe
- 5 mL per 60 gallons, twice weekly, from a measured cap
- It contains no nitrogen and no potassium, only micros
- It assumes another source supplies the macros
- A long-time staple; owners note it does little run alone
- A good micro top-up, but the common mistake is treating it as complete. In a lean tank, plants still starve without a macro source
Cheap and widely available. As a supplement it stretches a long way, but budget for a macro source too if your tank is lean, otherwise you are only supplying half of what plants need.
- Running it as the only fertiliser, so plants stall for lack of macros
- Overdosing iron chasing growth it cannot deliver alone
- Assuming it is equivalent to an all-in-one like Thrive
We do not bench-test this; the assessment synthesises the manufacturer's stated specification and aggregated owner feedback. We give gear and method guidance only. For a fish's specific health or diet needs, consult a veterinarian or an established authority.
No. It is micros and trace elements only, with no nitrogen or potassium. Pair it with a macro source or use an all-in-one instead.
Because it supplies no nitrogen or potassium. In a lean tank, plants need those macros from fish waste, root tabs or a macro fertiliser.
Thrive is an all-in-one with macros and micros. Flourish is a micro supplement. For one bottle that does everything, choose Thrive.