NO3 is a compound usable by plants.
They will do the job for you, all you have to do is harvest them. That will
also take care of the PO4 and other nutrients.
iy
"George Patterson" wrote in message
news:r%t8h.4864$J5.1127@trnddc04...
wrote:

Might be better to stand the question on it's head and ask those who do
water changes "what do you think they achieve". I don't need to remove
NO3 (It varies between 0 & 5ppm) or PO4 or anything else I can think of
right now.

I need to remove NO3.

George Patterson
Those who do not study History are doomed to repeat it. Those who DO
study History are doomed to watch every one else repeat it.