Sulfur Denitrator startup, bubbles forming

[sczlars]

I have a 90g display with rather high Nitrates; trying to finally get this under control by using a sulfur denitrator, I have the small Aqua-maxx. The problem I'm having is with the 1 drop/second for a while, I get gas forming inside (not the sulfur smelling kind), that I then worry will be too much and damage the recirculation pump. I can let it out through the vent valve, but at the slow flow it just creates more. I had one day where it seems it was dialed correctly where at 1dr/sec I had like 0.1 nitrates in the effluent, so I turned up the flow to 2dr/sec, but then the air inside accumulated again and got in the way (I turned up the flow to get rid of it, and I suppose reset the unit again). Thanks for any advice, comments, etc. --Lars

 

[sczlars]

bump.. any ideas, folks?

 

[Randy Holmes-Farley]

I've not use a sulfur denitrator, so I'll leave the procedural advice to those who have, but the gas production (if it is N2 and not something else) is likely to decline once nitrate comes under initial control.

 

[Jb2344]

Are you still having problems with this?

 

[sczlars]

Well, I just kept the flow at a slow dribble, and kept burping it if of N2 gas, and eventually realized that it had been bringing the tank's nitrates down, so that is good. I've understood it can be tricky to get these going if nitrates are really high, and mine were. 75+ (maybe up to 100ppm), but once it got down to a range I could actually track accurately (Hanna test) I could at least see what was going on and adjust things from there.

Nitrates are now down to about 20ppm and still falling, and the unit is behaving easier now. Effluent today read 0.0 at about 4 drops/sec, so I'm slowly increasing now. Thanks for checking in.

 

[Rmckoy]

A few years ago I’ve considered adding one to my system but there wasn’t enough information to rely on it .
I’ve went with cheato which has worked for me .

 

[kboogie]

Well, I just kept the flow at a slow dribble, and kept burping it if of N2 gas, and eventually realized that it had been bringing the tank's nitrates down, so that is good. I've understood it can be tricky to get these going if nitrates are really high, and mine were. 75+ (maybe up to 100ppm), but once it got down to a range I could actually track accurately (Hanna test) I could at least see what was going on and adjust things from there.

Nitrates are now down to about 20ppm and still falling, and the unit is behaving easier now. Effluent today read 0.0 at about 4 drops/sec, so I'm slowly increasing now. Thanks for checking in.

It took over a month for you to start to get zero nitrates from your effluent? How do you burp it to let the air out?

 

[sczlars]

Well, I had a couple of times when I tested the effluent and it was 0, so I sped up the flow a little, probably too much, and got way more than 0 coming out (possibly nitrite that also registered on the nitrate test), but also got a lot of gas forming. Keep in mind I had 75ppm+ NO3 in the tank at the time. What I ended up doing was keep it flowing slow enough that bubbles would form, and vented the gas out via the vent valve twice or three times a day. I have the AquaMaxx unit. Eventually my tank water started testing less than 75ppm on the Hannah kit, and I just kept that system going now that I saw that it was working. Once the nitrates got below 20 or so, less NO2 gas was forming.

 

[sczlars]

I see you got the same one as me. Ok, since I just gravity feed mine (siphon from the display), I turned off the recirculation pump of the unit, then put a finger over the outflow tube end to stop the flow, then reached up and held down the white ring with a fingernail, while I pulled the blue plug out from the vent valve. Then I rocked the unit back and forth until the gas was out of it. I'd also plug the vent hole with my finger to let a little pressure build up, which then helped burp more gas out. I suppose as long as your pump is moving the water slowly, that would work for you as well. A bit fiddly, but I got the hang of it after a few cycles