DIY NoPOx dosing, still have Nitrates need help

[amcvay1979]

Hello all. I'm at a crossroads. My tank is looking great, fish are all fat and happy and my skimmer is producing some of the thickest, greenest, most foul smelling sludge I've ever seen. I've been dosing 60%/40% vinegar/vodka around 12 to 15ml per day for well over 2 months now and my Nitrates don't seem to fall below 7 to 10 ppm. My phosphates are all but zero and I have absolutely no algae in the tank.

I do have some spots of cyano but it's largely cleared up and only 2 smaller spots in a dead zone.

I have a VERY heavy bio load consisting of;
1 violet tang
1 tomini tang
4 female lyretail anthias
1 male stocky anthias
6 chromis
2 tomato clows
1 melanarus wrasse
1 six line wrasse
2 cardinal fish
1 jawfish
1 clown goby
1 mandarin

22 fish, ya I know

My tank is a 150 tall with mostly pukani dry rock and the rest is all dry rock, roughly 150 lbs. Sand bed is about 2 - 2.5 inches of medium grain sand.

Currently I feed Rods, Docs Eco Eggs, frozen brine and cyclopeez, all mixed together, each one less than the size of my pinky nail, this is 1 batch, and I break it up into 4 feedings per day. It's a feeding frenzy and nothing goes to waste, even the corals get fed with this mixture, every fish eats something out of this mixture, even the jawfish and mandarin.

So I'm assuming my heavy bio load is causing my nitrates to hold steady at less than 10 but never under 5 ppm. My corals consist of mostly LPS, mostly frags and all are doing quite well. I have about 7 or 8 colonys of LPS and frags, some zoas, some mushrooms and a birdsnest, 2 goniapora colonies, and 1 alviapora frag.

My skimmer and the DIY NoPox are my only nutrient export (20% water changes monthly as well) so I was thinking about either adding some sort of denitrator like a coil system or perhaps and refugium. My sump is full so I'd have to mcgeyver a fuge system, but it could be done. I've removed my filter socks completely from the sytem, and all that's left for mechanical filter is one sponge right before the return pump to eliminate micro bubbles. It also grows pods like mad, so I don't really want to get rid of it.

Typically I've never seen water changes of 30 gallons make any sort of dent in Nitrates in this system, so I'm wondering if a fuge is the way to go? I could easily increase total water volume by 30 gallons or so if needed, but I don't see that as a good answer either.

Thoughts? Any help is much appreciated.

Current tank parameters
150 tall (48L x 24D x 30H)
Salinity: 1.026
Temp: 78-79
Alk - 9.2
Cal - 440
Nitrate - 10ppm
Phos - 0.02 ppm

Not dosing anything at the moment other than DIY NoPOx, 60% white vinegar/ 40% vodka 80 proof. shooting for 15 ml per day until nitrates fall below 6 ppm, then I dropped to 12ml but Nitrate shot back up to 10. So I'm back to 15ml per day.

 

[bertoni]

If I wanted to drop the nitrate level, I'd probably try a denitrator of some sort in this situation. The nitrate level might be fine as is, though. The corals all seem to be doing well, from your description. Are you trying to work on coloration?

 

[amcvay1979]

Not coloration so much, I'm kind of just chasing that magic zero number. But maybe I shouldn't be concerned too much?

My focus is more on growth vs coloration, so perhaps I should just roll with having some Nitrate in my system while my colonies are growing?

Maybe I should consider it a successful system feeding such a large number of fish and only having N at 5 to 10?

 

[tmz]

I wouldn't set 0 for NO3 as a goal; nitrogen deficiencies may occur. I prefer it under 1 or 2ppm though.
I know some cases where it took 5 or 6 months to fall with organic carbon dosing. Those bacteria go for the N in ammonia preferentially , so the nitrate production from ammonia is redcued.. However, the baseline level of NO3 may be slower to decline from normal assimilation and/or anaerobic activity.
When I started dosing vodka and vinegar in proportions close to the NOPOX about 7 years ago , nitrates where above 50ppm. I reduced them with a sulfur denitrator before dosing organic carbon and then established a maintenance dose which, despite very heavy feeding for about 50 fish .holds PO4 in the 0.02 to 0.04 ppm range with NO3 around 0.2ppm.

With 7ppm, I'd probably just wait it out for another month or too, since it's not a terribly high level . If you want it lower fast a sulfur denitrator will do it.

 

[amcvay1979]

Thanks for the tips. I'm going to up the dosage to 20ml per day of my DIY NoPOx as that's closer to what Red Sea dosing instructions call for and see how that works for about 2 weeks.

 

[tmz]

You are welcome. Good luck and let us know how it turns out.

 

[amcvay1979]

Nitrates now at zero thanks to increasing flow, changing filter socks as soon as they're clogged and moved my skimmer bubble level in the neck down and within 3 days my nitrates went from 5 ppm to zero. Finally found the magic combination!