I dabbled in FW plenums for a few years, and yes, they did work, but so what? I still did the sane pecent partials with or without plenums. Nitrate is a pollution indicator, it is on its own only a part of pokkution but the easiest indicator in unplanted, non-plenum, non-coil denitrator tanks.
If you have a disability which does not allow lifting/moving weights (as in buckets of water), get another job and buy a Python, or don't try to keep fish if you cannot do it properly.
If you have a disability which does not allow lifting/moving weights (as in buckets of water), get another job and buy a Python, or don't try to keep fish if you cannot do it properly.