Phosphates in a Fish Tank

Earlier this week I mentioned that I got high levels of phosphates in my infant tank, which caused an algae bloom. I traced it back to my water supply. How did I do that? Easy. I have a white bucket in which I pour new water straight from the tap, add the necessary chemicals (Prime, Ph balance, aquarium salt) and use it while replacing the water during water changes. So when I am running water straight from the tap into that bucket and I see it turn green or brown, I know my water source is contaminated.

But are there other causes for high phosphates, which in turn lead to algae blooms?

Yep.

If you are overfeeding your fish, the breakdown of the food often raises phosphate levels. A fish's stomach is roughly the same size as their eye.

Some manufacturers use phosphates in their flake food. Do some research and select one lower in phosphates. I use Tetra flakes and have not had a problem.

Clean the fish tank on a regular basis. Fish waste, uneaten food, plants decaying, or God forbid a dead fish left in the tank, will all raise phosphate levels.

Get some cleaner fish to help get rid of uneaten food that falls into the gravel. I love keeping corydoras with my angelfish. They are both very peaceful and while the angels tend to stay in the middle of the tank, the corys prefer to hang out at the bottom - except when they party while the angels sleep. Snails and a pleco will also help to keep algae levels down.