Nitrate problem.....maybe?

[mrtint]

I need some advise please.

I'm new but not new to the hobby!HAHA
what i mean is I have been out of the hobby for 12 years but could not shake the bug so I set up a mini version of my old successful tank. The biggest difference today is the lighting (LED) and the testing (chemistry) 12 years ago it was all about metal halides and VHO bulbs. Testing (other than CA and No4) was only done to find a problem if you had one. my corals grew like weeds in my old tank along with the coraline algae. My current set up seems fine but my nitrates are high.
tank specs

30gal tank
5gal sump/fugium
live rock and base rock mix 75% live 25% base
2.5" live sand bed 2" in sump
2 12" LED 445 blue strips
1 12" LED 50/50 blue/white strip
chiller (coral life)
doser (eshopps)
neptune controler (lights,powerheads,temp,ph,orp)
ATO
skimmer (aqua Maxx)

water specs
CA 520 (currently not dosing CA to get it back down) old salt mix was raising CA way to high....switched to Tropic Marine and CA is slowly coming down
Alk 9.0 (dosing 7mil a day to keep it there)
Mg 1300 (30mil a day but decreasing now...was at 1200)
PH 8.2
PO4 0.0
No3 40+ppm (was at 50ppm) but 5gal water changes is lowering it

All test are done with Salifert test kits
water top off is done with RO (tests are good for source water)
water changes with RO and now using Tropic Marine salt

my plan currently is to:
1) continue more aggressive water changes to lower No3
2)add more macro to fugium
3)use red sea No3o4-X to increase live rock performance of reducing No3
4)eliminate cause of excess nitrate (but what is it)

ALL THAT FOR THIS Question
What is causing High nitrates?

My suspicion is the number one cause of high nitrates.....over feeding.....so please tell me if I am. Here is how I feed
Daily
-flake food for my clown and 2 fire gobys. just enough that they each get a couple flakes if something hits the ground my hermits or brittle star are all over it
-Only one of these below......I rotate between them
5mil Reef Vital or
5-10mil reef snow or
5mil ChromaPlex or
5 drops of oyster feast
-once a week I skip all that and feed one cube of frozen brine mainly for my clean up crew but the whole tank loves it

ANY HELP ADVISE would be greatly appreciated! Thank You in advance.

PS....This all came about cause I have one coral (golden hammerhead) that was huge for one head....... it split into 2 heads the first week I had it and now never opens up. Its right in the middle of the tank center half way up

pics for reference

 

[boxfishpooalot]

I'd suspect the sand bed. It gets full fast. In my bare bottom system (with a painted white bottom - I like the look of sand) I have zero po4 and zero no3 according to tests. One time I had nitrates at about 20-30ppm. I couldn't figure out why, there wasn't a spot of food anywhere or detritus. Turns out the chaeto had accumulated tons of stuff in its jungle. I removed 75% of it and after a few days zero no3.

 

[mrtint]

interesting! I thought the sand was there to help with nitrates not make it worse. I know I use to have a deep bed in my last tank with no problems. As far as the chaeto......you may be on to something. I looked at it and it is full of all kinds of stuff. Think ill shake it out in the old water on my next water change. thank you for the reply

 

[dinonightmare]

Only deep sand beds can hold the bacteria that consume nitrates. If your sand bed is less then 3 inches it won't hold that kind of bacteria and will hold other stuff that will decompose and turn into nitrates (uneaten food and fish droppings).

 

[purge43]

I always found the no3 test by salifert hard to see the color. your eyes are probably much better then mine, but I use the api for no3

 

[bertoni]

Well, the sandbed might be helping a bit with consuming nitrate, or it might have collected a lot of debris that is releasing nitrate. If the sand is fine enough, it likely won't have collected enough debris to be a problem. My first guess is that the tank is getting too much food for it to handle, but some filtration media, like bio-balls or ceramic rings, can increase the nitrate level in the system, as well.

 

[mrtint]

Thanks Guys for the help.

Do you suggest removing the sand bed all together or vacuum the bed. dont really want to remove but will if its a common issue of causing high nitrates. it is very fine sand so I dont think it will vacuum very well

 

[bertoni]

I would ignore the sandbed for now, and give the Red Sea product and other steps some time to work. They might solve the problem, or more might be needed.

 

[Dan_P]

Is this a fairly new system? If so, I would guess denitrification not very robust yet. So, at this point the bioload is too high, but in a few months probably not. Your plan of action seems reasonable.

 

[GainesvilleReef]

I think your suspicion is correct. I would cut back on the coral food. Maybe to once a week or not at all. Also, an entire cube of frozen food is a lot. I feed my 30 gallon about 1/8 of that a day and no coral food and the corals grow like weeds.