Filter Media & Cleaning

API Bio-Chem Stars

Freshwater & marineBiological media

API Bio-Chem Stars are biological filter media — permanent housing for the nitrifying bacteria that turn ammonia into nitrite and nitrate. Each 2.5 cm star is made under a patented process that creates an internal pore network of 50 to 70 microns, the size range those bacteria colonise best, and the open polymer structure lets oxygen and water move through freely so the colony stays active. API rates the stars at four times the surface area of ceramic rings. Rinse them, put them in the last stage of the filter, and they are colonised within a few weeks. Twenty stars serve tanks up to 380 litres, freshwater or marine.

View at Jungle Aquatics

Live pricing and stock on jungleaquatics.com — purchase through Jungle Aquatics, with delivery across South Africa.

Dosage calculator

Enter your aquarium volume and the calculator works out how much API Bio-Chem Stars to use for each rate on the pack.

Aquarium volume

Measured in

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

Stars needed20 stars per 380 litres
Enter a volumePermanent media — never replaced, only rinsed in tank water

Place them in the last stage of the filter, after the mechanical media.

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	Biological filter media — porous polymer stars
Treats	Up to 380 litres (20 stars)
Star size	About 2.5 cm across
Pore size	50 – 70 microns
Surface area	About 4 × that of ceramic rings
Suitable for	Freshwater and saltwater aquariums
Lasts	Indefinitely — never needs replacing
In the box	20 stars (media bag not included)
Made by	Mars Fishcare, USA

How many stars does my tank need?

The pack of 20 stars is rated for aquariums up to 380 litres, so one pack covers most home tanks and two packs a large display. Put them in the last compartment of a canister or the rear of a hang-on filter, after the sponge, so they stay clean, and give them a few weeks to colonise — adding Quick Start seeds them immediately. Unlike sponges and carbon they never wear out; rinse them gently in a bucket of tank water when the filter is serviced and put them straight back. Do not replace all the media in a filter at once, or the bacterial colony goes with it.

A permanent home for the filter bacteria

Biological filtration is the bacteria that live on surfaces inside the filter. The more surface there is, and the better oxygenated it stays, the larger and more resilient the colony. Bio-Chem Stars are engineered for exactly that: a pore size matched to nitrifying bacteria and a structure that does not clog.

Four times the surface area of ceramic rings

Ceramic rings are mostly solid with a thin porous skin; the stars are porous through and through. API puts the colonisable surface at four times that of rings for the same volume, which means more filtration from the same basket.

Last stage of the filter, never rinsed in tap water

Place the stars in the final compartment so water reaching them is already free of debris. When you clean the filter, rinse them only in tank water; chlorine in tap water kills the colony you have spent weeks growing. No media bag is included — use one if your filter needs it.

Frequently asked questions

Can I use Bio-Chem Stars in a marine tank?

Yes. They are biological media for freshwater and saltwater aquariums alike.

How big are the stars?

Each star is about 2.5 cm across — small enough for a hang-on filter, with no stiffness to worry about in a canister basket.

Do they come with a media bag?

No. Use a mesh media bag if your filter has open compartments, or place them loose in a canister basket.

How long until they work?

Bacteria colonise the stars within several weeks. Dosing Quick Start at the same time speeds the process.

Are API Bio-Chem Stars available in South Africa?

Yes — Jungle Aquatics in Fourways, Johannesburg stocks the 20-star pack and delivers nationwide; live pricing and stock are on jungleaquatics.com.

Stocked & supported by Jungle Aquatics

South Africa's leading pet and aquarium store since 2007 — with the API range on the floor in Fourways, advice from people who test water every day, and easy ordering from anywhere in the country.

Visit or contact the store Shop online →