Not all algae are green and not all algae are minute in size

This is a 250 word (approx) summary of a chapter from my book ... The Complete Pond Solver

Like most of us the more food, the more oxygen and the more sunlight the better and bigger the algae grow.

Not all algae are green and not all algae are minute in size and nor do they all remain suspended in water giving that pea-soup appearance.

First of all the usual problem of green water (sometimes brown) which does not go clear and even after changing the water the algae re-appears very quickly and this happens even if you have a filter installed.

The reason why algae is not removed in many filters is due to its small size if the medium in your filter has gaps/pores greater than 4 microns in size then the algae will just get recirculated.

By the way most filters suffer from this design problem so do not think it is a problem with yours.

Algae growth is most common in ponds where conditions are most suited to their requirements lots of fish being fed lots of food, warm water as it is in summer here, and strong sunlight.

The waste products from fish eventually create nitrates in the water and most pond food contains phosphates and lots of nitrogen.

These are fertilisers for plants as you know from general gardening.

Algae that grow to about 1 cm in length and are seen on pump surfaces, rocks, pump filter sponges and the sides of ponds are normal.

Do not try to remove them by sweeping the pond walls for example because they will keep coming back and if left alone reach an equilibrium point.