Filter causing the nitrates?

[Mikeaveli21]

Ok I checked my water today and got:

phosphate-1.6
N03- 20 ppm
N02- 0 ppm
pH- 8.2
Salinity- 1.022
temp- 79
Nh3-0
calcium 450

I have done tons of water changes over the last few months and can't get my nitrates down. So I have come to the conclusion that its my filter that causing the problem.

The filter is one of those millenium 3000's (got it for free so stuck with it) that has a BIO GRID, which harbors the bacteria, and carbon filled cartridges that get replaced. Is this bacteria grid plate causing these high nitrates? Should I take them out and place some pieces of LR in the filter instead?

Also Any ideas why my phosphates are at 1.6? I am not over feeding and only use RO/DI water. Any ideas? Thanks

[anemoneman]

Just remove the bio grid, there's no need to put LR in your filter housing (waste of LR). Add more LR to your tank if you think you need it.