Plant Care

API Leaf Zone

FreshwaterPlant safe

API Leaf Zone is a liquid fertiliser for freshwater planted aquariums. It supplies chelated iron and potassium in a form plants take up directly through their leaves, so stem plants, mosses and floating plants respond to it quickly. Iron is the nutrient that keeps new leaves a deep green or red rather than pale and washed out; potassium supports steady growth across the whole plant. Dose 5 ml per 40 litres once a week. It comes in 237 ml and 473 ml bottles, treating about 1 794 and 3 581 litres, and API recommends pairing it with Root Tabs for plants that feed through their roots.

Size: 237 ml

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Dosage calculator

Enter your aquarium volume and the calculator works out how much API Leaf Zone to use for each rate on the pack.

Aquarium volume

Measured in

Use the water the tank actually holds, less substrate and decor.

Weekly dose5 ml per 40 litres
Enter a volumeOnce a week, after the water change

Work from the water the tank actually holds, less substrate and hardscape.

A guide only — always follow the dosing instructions printed on the pack, and measure with the bottle's cap or a syringe rather than by eye.

Technical details

Product type	Liquid plant fertiliser
Sizes	237 ml and 473 ml
Dose	5 ml per 40 litres
How often	Once a week
Treats	237 ml treats 1 794 litres; 473 ml treats 3 581 litres
Key ingredient	Chelated iron and potassium
Suitable for	Freshwater planted aquariums
Safe with	Fish, shrimp and snails
Water change needed	No — dose after your normal weekly water change
Made by	Mars Fishcare, USA

Pair with API Root Tabs for swords, crypts and other plants that feed mainly through their roots.

How much Leaf Zone do I dose?

Add 5 ml for every 40 litres of aquarium water once a week. A 60 cm tank holding around 50 litres after substrate and hardscape takes roughly 6 ml; a 200-litre tank takes 25 ml. Dose after the weekly water change so the fertiliser goes into fresh water, and stick to the measured amount: iron and potassium feed algae as readily as they feed plants, and a smaller dose is less likely to set off a bloom than a generous one. At that rate the 237 ml bottle treats about 1 794 litres and the 473 ml bottle about 3 581 litres, which on most tanks means months of weekly dosing from one bottle.

Feeds through the leaves, not the roots

Leaf Zone is formulated for fast uptake through leaf tissue, so it starts working as soon as it disperses in the water. That makes it the right feed for stem plants, floating plants, mosses and anything tied to driftwood or rock with no real root system in the substrate. Root feeders still benefit, but they do better with a tablet at the roots as well.

Chelated iron and potassium for colour and growth

The two nutrients Leaf Zone supplies are the ones a home aquarium most often runs short of. Chelated iron stays dissolved and available to plants instead of precipitating out, and it is what turns pale, yellowing new growth back to a strong green or red. Potassium supports steady, even growth across the whole plant.

One weekly dose of 5 ml per 40 litres

Dosing is simple: 5 ml for every 40 litres of aquarium water, once a week. The routine slots in neatly after a weekly water change, when fresh water has diluted whatever was left of the previous dose. Work from the volume the tank really holds, less substrate and hardscape, and measure the dose rather than guessing, since a heavy hand feeds algae before it feeds plants.

Safe with fish, shrimp and snails

Nothing needs to come out of the tank when you dose. API confirms Leaf Zone is safe in aquariums with fish and with freshwater invertebrates such as shrimp and snails, so it suits community tanks and dedicated shrimp tanks alike. It is made for freshwater aquariums only.

Frequently asked questions

Is Leaf Zone safe in a shrimp tank?

Yes. API states Leaf Zone is safe with freshwater invertebrates, including shrimp and snails, and with fish, so nothing needs to leave the tank while you dose. It is a freshwater product and is not intended for marine aquariums.

How long will a bottle of Leaf Zone last?

The 237 ml bottle treats about 1 794 litres in total and the 473 ml bottle about 3 581 litres. On a 100-litre tank that works out to roughly 18 weekly doses from the small bottle and 36 from the large one.

Do I still need Root Tabs if I use Leaf Zone?

For a tank of stem plants, mosses and floaters, Leaf Zone on its own does the job, because those plants feed through their leaves. Heavy root feeders such as Amazon swords and cryptocorynes do best with API Root Tabs in the substrate as well, and API recommends using the two together.

Will Leaf Zone cause algae?

It can if you overdo it. The same iron and potassium that feed plants will feed algae, and API notes that smaller amounts are less likely to trigger a bloom, so keep to the measured dose, give plants enough light to use the nutrients, and cut back if green water or hair algae appears.

How quickly will I see a difference?

Leaf Zone is formulated for rapid absorption through the leaves, so plants can use it almost as soon as it disperses. Judge results on new growth over a few weeks of consistent weekly dosing: fresh leaves come through greener and better coloured, while older, already-pale leaves are slower to change.

Is API Leaf Zone available in South Africa?

Yes — Jungle Aquatics in Fourways, Johannesburg stocks both the 237 ml and 473 ml bottles and delivers nationwide, with live pricing and stock on jungleaquatics.com.

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