Pond Care

API Pond AlgaeFix

PondNot for crustaceans

API Pond AlgaeFix controls the algae that turns a pond green and clogs it with weed: green water blooms, string or hair algae (Cladophora) and blanketweed (Oedogonium). It is fast-acting, and continued weekly dosing controls new growth as well as existing algae, which is what keeps a pond clear through a hot summer. Dose 5 ml per 189 litres every three days until the algae is under control, then once a week. Measure the pond first and never overdose. It must not be used in ponds containing freshwater crustaceans — shrimp, crabs or crayfish.

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Dosage calculator

Enter your pond volume and the calculator works out how much API Pond AlgaeFix to use for each rate on the pack.

Pond volume

Measured in

Use length × width × average depth in metres × 1 000 = litres.

Algae control dose5 ml per 189 litres
Enter a volumeEvery 3 days until algae is controlled, then once a week

Keep pumps and aeration running throughout. Not for ponds containing shrimp, crabs or crayfish.

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 pond algaecide
Pack size	473 ml
Dose	5 ml per 189 litres, or 60 ml per 2 271 litres
Schedule	Every 3 days until controlled, then weekly
Controls	Green water algae, string or hair algae, blanketweed
Suitable for	Ponds, water gardens and fountains with fish and live plants
Do not use with	Freshwater crustaceans — shrimp, crabs, lobsters or crayfish
Made by	Mars Fishcare, USA

Determine the pond volume before the first dose and never exceed the label rate.

Is AlgaeFix safe for my koi and pond plants?

Yes — it is labelled for ponds and water gardens containing live plants and fish, including koi and goldfish, provided you dose to your measured pond volume and never overdose. What it must not go near is freshwater crustaceans: shrimp, crabs, lobsters and crayfish are killed by it. Keep aeration running for the whole course, because the bacteria that break down dying algae consume oxygen and a hot, algae-choked pond is already short of it. Net out heavy mats of dead blanketweed rather than letting them decay in the water, and dose 5 ml per 189 litres every three days until growth stops, then weekly.

Green water, hair algae and blanketweed

The three algae problems that ruin a pond in summer are pea-soup green water, the hair algae that drapes off rocks and the blanketweed that fills the shallows. AlgaeFix is labelled for all three, in water gardens, ponds and ornamental fountains that contain live plants and fish.

Knock it down, then keep it down

The first phase is a dose every three days until the algae is controlled. After that, a single weekly dose stops new growth taking hold and cuts the amount of maintenance the pond needs. Add it near the pump outflow, waterfall or aerator, or mix it in a bucket and pour it evenly round the pond.

Aerate while the algae dies

Dying algae is broken down by bacteria that consume oxygen, and a warm South African pond holds less oxygen to begin with. Keep pumps, waterfalls and aerators running throughout treatment, dose in the morning rather than at night, and remove large mats of dying weed with a net rather than leaving them to rot.

Frequently asked questions

Can I use AlgaeFix in a pond with shrimp or crayfish?

No. The label specifically warns against use with freshwater crustaceans including shrimp, crabs and lobsters.

How often do I dose it?

Every three days until the algae is under control, then one dose a week to prevent regrowth and reduce maintenance.

Where should I add it?

Near the pump outflow, a waterfall or an aeration device so it mixes thoroughly, or diluted in a bucket and poured evenly around the pond.

Does it work on blanketweed?

Yes. It is labelled for blanketweed (Oedogonium) and string or hair algae (Cladophora) as well as green water blooms.

Is API Pond AlgaeFix available in South Africa?

Yes — the 473 ml bottle is available from Jungle Aquatics in Fourways, Johannesburg, with delivery nationwide; live pricing and stock are on jungleaquatics.com.

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