API Leaf Zone (18 oz)
A cheap liquid, but a limited one: Leaf Zone is essentially iron and potassium, with no nitrogen or phosphorus. Fine as an iron/potassium top-up, not as a tank's only fertiliser.
- +Very cheap and widely stocked — an easy iron and potassium top-up for green, leafy growth
- +Chelated iron and potassium keep leaves green; dilutable and easy dosing by the measured cap
- +Low phosphate and gentle, so it is shrimp safe with no algae bloom
- +A measured cap makes dosing a community tank simple
- −Missing nitrogen and phosphorus — it is really an iron and potassium supplement, not a complete fertiliser
- −Plants in a lean tank still need a separate nitrogen and phosphate source alongside it
This is API Leaf Zone, a cheap liquid that is essentially iron and potassium, with no nitrogen or phosphorus. It is an iron and potassium top-up for green leafy growth, not a complete fertiliser, so plants in a lean tank still need a separate nitrogen and phosphate source.
- An inexpensive iron and potassium top-up
- Tanks that get nitrogen and phosphate elsewhere
- Keepers wanting greener leaves on undemanding plants
- Use as a tank's only fertiliser, since it has no N or P
- Lean tanks with hungry plants
- Anyone who wants a true 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.
- Chelated iron and potassium
- No phosphate; shrimp safe
- 5 mL per 10 gallons, twice weekly, measured cap
- It provides potassium and iron only, no nitrogen or phosphorus
- It is a supplement, not a complete fertiliser
- Cheap and widely stocked; owners note it is limited alone
- Like Flourish, easy to mistake for complete. It greens up leaves but will not feed a lean tank on its own
Very cheap and widely available. It stretches a long way as a supplement, but budget for a nitrogen and phosphate source too if your tank is lean.
- Running it as the only fertiliser, so plants stall for lack of N and P
- Chasing growth with more iron than plants can use
- Assuming it is a complete all-in-one
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 essentially iron and potassium, with no nitrogen or phosphorus. Pair it with a macro source or use an all-in-one.
It can green leaves if iron or potassium is the limit, but pale, stunted growth in a lean tank usually means missing nitrogen, which this does not supply.
Thrive is a complete all-in-one; Leaf Zone is an iron and potassium supplement. For one bottle that does everything, choose Thrive.