do algae use nitrate? i have some algea issues, am notcing the algae tend to pearal more than my plants? my nitrate was high so was my po4? am doing 50% twice a week now? my nitate is around 16, was in the 40 range and my po4 is in the 2 range used to be in 3-4 range? co2 at 30? i decreased my ligts to 75w over the 29g?
should i push the nitate higher and drop the po4?
thanks

Generally, 20-30ppm for NO3 is fine.
20 is a nice target.

That gives a rather robust wide range of 10-30ppm at any one time.

PO4, as long as you add a fair amount, 2-3ppm per week, no need to worry there with the water changes(50% or more).

Regards,
Tom barr

my Po4 straight from the tap is often 10ppm! but i am currrently ignoring this because of my distrust of test kits and my water suppliers abbility to maintain any constant levels of anything accept H2o and therefore i am continuing to dose PO4 as if i have none without any major algae isues.

It sounds like you have a fair bit of light, if your co2 levels are not adequate to support that much light you will also end up with algae problems. If that's the case you need to reduce light or increase co2.

Yes, generally most issues arise via CO2 problems keeping it stable or high enough, that goes for testing as well.

So most of the focus should be placed on CO2 and moderate, not high light.

Regards,
Tom Barr