Phosphate readings accuracy

[Spelter]

How accurate is the test if you already have nuisance algae? 

 

 

I've been battle algae for months now. Tank is almost 1 year. Sand bed is finally clear but still grows thickly on rocks and glass. 

[scott711]

it could mean that you still have phosphates in the tank.  Algae consumes phosphates.

[Spelter]

I get a reading of 0-0.2 with my new test kit. Thats why Im wondering if something else is feeding this outbreak. 

[Origami]

The test measures phosphates left in the water. Phosphates already consumed by the algae (or anything else for that matter) is not available to the test to be measured. In essence, the algae is cleaning your water as it grows - it just looks bad in your tank, that's all. The fact that you have an ongoing algae problem says that the nutrients (phosphates, nitrates, etc.) are available to sustain their growth. Does that make sense?

[Spelter]

Yes I understand. I am just trying to find my source of nutrients. Just ordered a new bulbs as I that is one factor I have not played with yet. 

[Origami]

Why new bulbs? They're not a direct source of nutrients. The most direct sources will be food that you're introducing to the tank, decaying organics, tainted change water, and possibly leaching phosphate from rocks or sand (under certain conditions).