Plant Care

API Root Tabs

FreshwaterPlant safe

API Root Tabs are fertiliser tablets that go into the substrate, feeding plants at the roots. Each tablet carries iron, potassium and carbon, the nutrients that keep root feeders such as Amazon swords and cryptocorynes green and growing instead of yellowing and shedding leaves. They are safe with tropical fish, and API recommends running them alongside a liquid fertiliser such as Leaf Zone so stem plants are fed too. Push one tablet midway into the gravel for roughly every 195 cm² of substrate, about a 14 × 14 cm patch, and replace them as plants use the nutrients up. A pack holds 10 tablets.

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Technical details

Product type	Substrate fertiliser tablets
In the box	10 tablets
Dose	1 tablet per 195 cm² of substrate (about 14 × 14 cm)
Treats	10 tablets cover about 1 900 cm² of substrate, roughly the floor of a 60 cm tank
How often	As needed; the nutrients are used up over time and must be replenished
Key ingredient	Iron, potassium and carbon
Suitable for	Freshwater planted aquariums; root feeders such as swords and crypts
Safe with	Tropical fish
Form	Tablet, pushed midway into the gravel
Made by	Mars Fishcare, USA

Push each tablet midway into the substrate rather than leaving it on the surface.

How many Root Tabs does my tank need?

Work it out from the substrate, not the water volume. API's rate is one tablet for roughly every 195 cm² of gravel surface, a patch about 14 × 14 cm. A 60 × 30 cm tank floor is 1 800 cm², so fertilising the whole bed takes about 9 tablets, close to a full pack of 10; a 90 × 45 cm floor needs around 21. In practice most keepers tab only where the root feeders are: one tablet beside each sword, crypt or Vallisneria, pushed midway into the gravel, and none under open sand. The nutrients are used up over time, so plan to top up as growth slows rather than treating a pack as a once-off.

Feeds plants where the roots are

Swords, crypts, Vallisneria and other heavy root feeders draw most of their nutrition from the substrate, so a liquid fertiliser in the water column only gets them part of the way. A Root Tab pushed into the gravel beside the plant puts iron, potassium and carbon exactly where the roots can reach them.

Iron, potassium and carbon in every tablet

Starved plants show it slowly: leaves yellow, thin out and eventually drop. Each tablet supplies iron for deep green colour, potassium for strong growth and carbon for building new tissue, and keeps releasing them as it breaks down in the substrate. New plants establish faster and settled plants keep pushing out leaves.

One tablet per 195 cm² of substrate

API's rate is one tablet for roughly every 195 cm² of gravel surface, a patch about 14 × 14 cm, so fertilising the whole floor of a 60 × 30 cm tank takes about 9 tablets. Most keepers simply place a tablet beside each root-feeding plant and leave open sand or gravel untreated. Push each tablet midway into the bed rather than leaving it on the surface.

Safe with tropical fish and pairs with Leaf Zone

Nothing needs to leave the tank when you add tablets. API rates Root Tabs safe with tropical fish and suggests pairing them with a liquid fertiliser, so the usual routine is a tablet at the roots of the heavy feeders plus a weekly dose of API Leaf Zone for the stem plants, mosses and floaters that feed through their leaves.

Frequently asked questions

Which plants benefit most from Root Tabs?

Root feeders: Amazon swords, cryptocorynes, Vallisneria and other rosette plants that draw their nutrition from the substrate. Stem plants, mosses and floating plants feed mainly through their leaves and are better served by a liquid fertiliser such as API Leaf Zone.

Where exactly do I put the tablets?

Push each tablet midway into the gravel beside the roots of the plant you want to feed, at a rate of about one tablet per 195 cm² of substrate. Burying it keeps the nutrients in the root zone where the plant can use them.

Do I still need a liquid fertiliser?

For a mixed tank, yes. API recommends using Root Tabs together with a liquid fertiliser, because the tablets feed the substrate and the liquid feeds everything growing in the water column; API Leaf Zone is the natural partner.

How long does a tablet last?

The tablet breaks down in the substrate and its nutrients are consumed gradually, so it is not a once-off. Watch new growth and add a fresh tablet when leaves start to pale or growth slows, and whenever you plant a new root feeder.

Are Root Tabs safe for fish?

Yes. API rates them safe for use with tropical fish, and you do not need to remove livestock when adding tablets. Push them in gently so you do not uproot neighbouring plants or stir up the bed.

Can I buy API Root Tabs in South Africa?

Yes. Jungle Aquatics in Fourways, Johannesburg carries the 10-tablet pack and ships nationwide; current stock levels and pricing are on jungleaquatics.com.

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