well the phosphate contribute towards the growth of algae as the tank was being treated for white spot for three weeks it hadn't been cleaned so i'm guessing this contrbuted towards the algae growth!
Ok so you are guessing, well i have proof, which clearly contradicts your theory, and is true. If you can run a tank with PO4 present, without any algae growth then that surely proves PO4 doesnt cause algae!?
In those three weeks, ammonia will of been produced, so those levels may have risen, the reason we do water changes is to remove toxins (ammonia), remove algae spores, and to replace minerals essential for fish growth,
but you say:
the water had a green tint, there was obviously fish and food waste present as it hadn't been vacuumed for the treatment period and we had a fish die that i thought looked as though it was having trouble breathing (rapid breathing motions darting to the surface!!!) so this would make sense
so i am pretty confident this is where the ammonia spike came from,
the plant it is completely healthy and is continously re-rooting spouting from the leaves and kept under control
thats good then, it is one factor we can rule out.
as in previous posts the ammonia 0 nitrite 0 nitrate 5
you didnt read my post properly, i said
undetetctable ammonia
and you say the PO4 levels rose, do you know these levels?
thanks,