5 GPD reverse flow 4" pumice bed, nitrate buster, denitratification

[markstrimaran]

Update.
Flowing 20 GPD. 0 ppm nitrates. Tank is still above 20 ppm.
Had to calibrate the ORP meter, as my old 0 ppm mv reading still had some nitrates,
My ORP probe is old and is only accurate as calibrated to a known value. Or perhaps the distilled water I added a few weeks ago tweaked it.
To calibrate it I just do hourly nitrate test as the mv numbers increase, when 0 ppm tests. That becomes the new bench mark. It was -2mv now it's + 5 mv. The ORP mv reading is very sensative to tiny changes.

 

[markstrimaran]

Sunday update is incorrect
ORP readings were both negative. - 49 and - 17.

 

[markstrimaran]

Update.
Tank nitrates are 5 ppm.
Flow 20 GPD
Carbon dose. 400 ml/day at 7 ml sugar per liter.

30 hours ago nitrates were 20+ppm.

 

[markstrimaran]

UPDATE: Silicate problem, diatomaceous brown stuff is growing. I am guessing that the pumice is leaching silicates.

Well pumice is NOT. At fault here as my 75 gallon tank, with no fish and no substrate, only green moss has brown age growing in it also.

In my 30 gallon the creek chubs keep the algae very thin.

 

[markstrimaran]

UPDATE. Changing title to, Contained Carbon dosing in fresh water aquarium.