Help: Sulfur nitrate filter with mv controller, "running in" duration ?

[Engaiauden]

Dear All,

I have a big NF1020 Deltec Sulfur nitrate filter with 27 Kg of sulfur inside.
It is regulated by a redox controller.
During the first days it started - 24 days ago - the redox inside the filter was about + 250 mv, today I register + 341 mv.
I know the maturation period can last up to 2 months (or more) without a probe and if you set one drop per second, but with a probe and no drops of fresh aquarium water (in my case I will have no drops until - 130 mv) is it normal that I register + 341 mv after so many days?
What measurements do you register during the start-up period with a redox controller?

Best regards
Stefano

 

[4alex]

24 days and redox value going up? Something wrong there.

I build a denitrator from an eheim professional II pot filter. To start it up i washed some bottom sand in tankwater and poored it in. The redox value went from +200 to -200 in about 8 hours!
The eheim is recirculating (output connected to the input) and a peristaltic pump (connected to the redox controller) pushes tank water in it. At the highest point in the filter (in case N2 gas forms) there is a airline tube to take the water back to the tank. I never see bubbles there tough. Took the nitrates down from 20 ppm to unmeasurable in about 1 month with about 300 gr of sulfur on a 150 liter tank.

Does the NF1020 have a pump to recirculate internally? Otherwise the redox sensor might not be able to measure the true redox potential inside the sulfur media.

Just my 2 cents,
Alex