Set up suggestions/advice for low nitrates

[jessezm]

Hey folks,
I'm running a 210g FOWLR. I set it up with cured liverock from a pristine reef tank (about 160lbs of tonga). It has an Oceanic 250 sump with bioballs. Skimmer is a Turboflotor 5000 shorty II, fed from one of the 4 drain lines. Also running an 18w turbotwist UV and carbon through a phosban reactor.

The tank is a community tank with inverts but no corals. It has been up for about 7 weeks, never showed signs of a cycle (due to fully cured rock transported in full water same day out of one tank and into the other?). Now, however, I'm observing a slow creep in Nitrates. They have been hovering around .2ppm but now appear to be closer to 2.5ppm (Salifert test). Now I know that is not high for a FOWLR, but I am also keeping shrimp, snails, crabs, and starfish, and am worried should the nitrates continue to creep.

The conditions in the tank have been very stable, NH4=0, PO4=.003, ALK/kH=9.3, Temp=79, pH=8.1-8.3.

Inhabitants include (in order of appearance):
Inverts:
45 Astrea snails
45 blue legs
45 scarlet reef hermits
5 emerald crabs
2 cleaner shrimp
3 peppermint shrimp
5 fighting conchs
1 brittle star (large, came with rock)
25 nessarius snalls
1 fire shrimp
2 choco. chip stars (one died already--never looked good from the beginning)
Sally light foot crab
Decorator Crab

Fish:
Flame Angel
2 Engineer Gobies (one started out sick and died, the other is great)
Scribbled Rabbit Fish (4")
Koran Angel (4" juvi)
Kole Tang (4-5")
Sailfin Tang (4")
Naso Tang (6-7")
Watchman Goby (4")

So here's my question: What should I do to reduce the chance of nitrates creeping up? (besides 20% water changes--so far, I've only done the first, but will do them bi-weekly to monthly)

Should I take the bioballs out of the sump? Unfortunately, I cannot turn it into a refugium do to high flow flow through the sump...

Flow from the return pump is about 1600-1800 gph, and is the only flow in the tank. Sandbed is about 2-4" of that bio alive aragonite reef sand (more where the engineer goby dumps his loads).

Any ideas? BTW, changing more water than that is pretty difficult, as this is a tank I'm taking care of at a bar, and not too close to where I live, either...

The owners feed the fish 1 or 2 times a day with vitamin-soaked pellets, frozen mysis, or prime reef, plus sheets of nori every other day.

 

[techigirl78]

Was this a transfer from an existing setup or have all of those fish been added over the past 7 weeks?

 

[jessezm]

They are all new--only the liverock and what came on it was transfered. I waited 2 weeks to add any animals, watching all the levels closely. when I got no significant cycle, with undetectable NO2, NO3, or Ammonia, and the starfish, snails, and other creatures that came in with the rocks (there were tons) were all doing great, I added a clean-up crew, shrimp, and the Flame angel. Waited another week and added the Rabbit and Engineer gobies. Two weeks later in went the angel, sailfin, kole, and chocolate chip stars. The engineer goby that had been struggling and listless since day 1 finally dissappeared, and later that week one of the chocolate chip stars that also looked bad from the beginning died. He never moved much or climbed on the glass like the other one, which is doing great. This past weekend I added the Naso and watchman goby after doing the first big water change (I aged the water for 1 week and buffered and heated to match tank conditions).

I've been visiting the tank twice a week and doing water tests, equip. checks, animal inspection, etc. The fish are all very healthy, voracious eaters, and get along great. I have observed some silt settling out in the sump in the bioballs section, as well as the return section.

I know the stocking was done rather quickly, though I have been monitoring water quality very closely. I want to prevent any deterioration and keep these guys healthy as can be.

 

[techigirl78]

Preventing deterioration of water quality would likely have easily been done by slowly adding fish. For a tank that size, I would say 2 medium fish per month would be a better rate to stock it. At this point, you should just continue to monitor the water quality and not add any more fish for a month or two. Let the system get adjusted to the load you put on it. Over time I would probably recommend adding some more live rock and removing the bioballs.

 

[jessezm]

Thanks, good advice. I know you're right on the stocking point--it's not my normal MO...

 

[xxseawolf]

wow macon ga. i grew up in warner robbins(demon country lol.)

 

[johno4]

From my understanding Cheato prefers a high flow, I would add a fuge with cheato.

 

[jessezm]

Ah, that's a good idea--I could harvest it and feed it to the tangs, too.

 

[lux_06]

id ditch the bio balls and get a deep sand bed and refuging in the system somewhere, just cant beat those 2 for easilily keeping nitrates down

 

[Nocturnal]

Simple: Lose the bioballs. Plumb in large remote deep sand bed = no nitrates

 

[jessezm]

I'm pretty sure the DSB won't be possible--The tank is out in the middle of a bar/restaurant, and everything has to fit under the stand... I'll ditch the bioballs and add cheatomorpha in place, but I don't think I'll be able to get sand to stay in the bioballs section--there's tons of flow and a few holes where sand would come out the bottom...

 

[Kahuna Tuna]

Simple: Lose the bioballs. Plumb in large remote deep sand bed = no nitrates

This is what I did (the remote sandbed, never had bioballs). If you cant do a sandbed the cheato is a good alternative. My nitrates have been at zero since the beginning and I feed fairly heavily.

Sounds like an awesome tank, do you have any pics? Would love to see it.

 

[jessezm]

I've been promising pictures for a long time! I will take some this week when I'm up there. I was just there today and the fish are all fat and happy. The Naso ate out of my hand! He's the only one in the tank that isn't eating pellets, still, but they get fed frozen mysis or prime reef every other day, plus sheets of nori so he's still staying bulky. Hopefully he'll start taking the pellets eventually (which are always vitamin and garlic soaked).