API Bio-Chem Zorb (210L)

• Three media in one pouch – ion-exchange resins, organic scavenger resins and activated carbon, rather than carbon on its own.
• Drop-in format – it arrives already bagged, so it goes into a canister, hang-on or sump wherever water is flowing past.
• Clears yellowing and odour – the two problems that make an otherwise healthy tank look and smell neglected.
• Removes medication after a course – API's own dosing instructions call for it 48 hours after the final dose of a treatment.
• Fresh, salt and reef – API rates it for all three, and states it will not release phosphates back into the water.
• Two-month service life – a fixed, predictable replacement interval rather than a guess.

About the 210 L in the title: API rates this pouch in US gallons only, at 55 gallons. That converts to 208 litres. The 210 figure is a rounded conversion that has travelled through the trade, not a number API publishes. We have kept it in the title so the product is still findable, and given you the real one here.

This is the question worth getting right, because API sells three different Zorb pouches and they do different jobs.

If your problem is a nitrate reading rather than a tint, this is the wrong pouch. Chemical filtration and nutrient export are different jobs and no single medium does both.

Take the pouch out of the filter before you start a course of treatment. It will adsorb the medication you are paying for and pull the dose below effective concentration.

Put it back after the course finishes, or fit a fresh one. API's own instructions for Liquid Super Ick Cure say to use Bio-Chem Zorb or activated carbon 48 hours after the final dose, which is exactly the right use for it: stripping the residue once the treatment has done its work.

This cuts both ways, and it is the most common mistake made with any carbon-bearing medium. Leaving it in during treatment is why a course sometimes appears not to work.

The Size 6 pouch is marketed for the Rena Filstar XP, API Nexx and Rena SmartFilter canisters. It is not restricted to them: it comes in its own flow-through bag, so it will work in any canister, power filter or wet-and-dry sump with room for a 283 g pouch in the water path.

Rinse the pouch under a tap first to wash off loose dust, then sit it where water is forced through it rather than around it. The pouch does not need to rinse clear before it goes in.

Media placed after mechanical filtration lasts longer. Put your sponge or floss upstream so the resin is not clogging with detritus it was never meant to catch.

API's product page says to replace the pouch every two months, or sooner if the aquarium is heavily polluted or colour and odour reappear. That is the figure to work to.

API's website FAQ separately describes its Zorb pouches as rechargeable by rinsing in warm tap water. We would not rely on that here. Carbon is not regenerated by rinsing, and unlike Nitra-Zorb, Bio-Chem Zorb has no published recharge procedure. Treat it as rinse-then-use, then replace.

Returning colour or odour is the practical signal that the pouch is spent, and it is worth acting on before the two months are up in a heavily stocked tank.

Bio-Chem Zorb is also distinct from plain activated filter carbon. API's argument for the blend is that the resins pick up organics the carbon does not, which is where the three-times-clearer claim comes from.

Suitable for:

• Freshwater, marine and reef aquariums up to about 208 litres
• Tanks yellowed by driftwood tannins, or smelling of organics
• Clearing residual medication once a treatment course has finished
• Canister, hang-on and sump filters with room for a 283 g pouch

Not suitable for:

• Removing ammonia, nitrite or nitrate. That is Nitra-Zorb's job
• Removing phosphate or silicate. That is Phos-Zorb's job
• Leaving in the filter during a course of medication
• Tanks over about 208 litres on a single pouch. Scale the number of pouches to the volume
• Planted tanks being dosed with liquid fertiliser, where chemical media works against the dosing

• API Freshwater Master Multi Test Kit 5 in 1 – tells you whether the problem is organics, which this pouch handles, or nitrate, which it does not.
• API Melafix – the pouch comes out while you dose it, and goes back in 48 hours after the last dose.
• API Quick Start – for restarting the biological filter after a treatment course.
• API Stress Coat – conditions the replacement water at the change you will be doing anyway.
• API Aquarium Salt – the freshwater tonic salt used during and after treatment.

This is a consumable filter medium, so no manufacturer warranty period applies. That does not affect your rights under the Australian Consumer Law: if the product is faulty, unsafe or not as described, you are entitled to a remedy.

Ships as standard freight. Store the pouch sealed and dry until you need it, as activated carbon adsorbs from air as readily as from water.

What size tank does API Bio-Chem Zorb Size 6 suit?

API rates the 283 g Size 6 pouch for aquariums up to 55 US gallons, which is about 208 litres. For a larger tank, use more than one pouch rather than expecting one to stretch.

Does API Bio-Chem Zorb remove nitrate?

No. API makes no ammonia, nitrite or nitrate removal claim for Bio-Chem Zorb, and assigns those to a different product, Nitra-Zorb. Bio-Chem Zorb targets colour, odour, dissolved organics, toxic gases, phenols and heavy metals.

Do I need to remove Bio-Chem Zorb when medicating my tank?

Yes. It adsorbs medication and will pull the dose below the level needed to work. Take it out before you start dosing, and put it back or fit a fresh pouch about 48 hours after the final dose to strip the residue.

How often should Bio-Chem Zorb be replaced?

API's own product page says every two months, or sooner if the aquarium is heavily polluted or colour and odour return. Some older packaging says monthly; two months is API's current figure.

Can Bio-Chem Zorb be recharged and reused?

API's website FAQ describes its Zorb pouches as rechargeable by rinsing in warm tap water, but API's own product page for this pouch says to replace it every two months and gives no recharge procedure. Since activated carbon cannot be regenerated by rinsing, treat this pouch as single-use and replace it.

Is Bio-Chem Zorb reef safe?

API rates it for freshwater, saltwater and reef aquariums, and its label states it will not remove trace elements from saltwater and will not release phosphates. API publishes no statement about its effect on pH or KH, so we make no claim there.