"Iain Miller" wrote in message
...

High phosphates are a known cause of Algae. To get rid of Algae you need
to get your plants
growing better - this will starve the algae out.

Iain, PO4 will not cause algae, neither will KH. Bad conditions for plants
is what causes algae. If you have good lights, co2 and are fertilising then
plants flourish, take away just one of the elements that they need (like
PO4) and you will get algae.

IMO, The OP needs to add some CO2 & NO3.
--
"In the beginning, God said the four-dimensional divergence of an
antisymmetric,
second rank tensor equals zero, and there was Light , and it was good."