How much is too much nitrate?

[jdewolftx]

Quick question....my tank is now 3 months old now (90g. / 40g sump) with TB live rock, radion x30 lights, and EM200 skimmer. I don't have any fish yet but I have 2 anemones, 3 cuc's, several sea urchins, and the rest of the cleanup crew. I also have a few candy cane coral, a hammer, and a montipora.

My ammonia and nitrites are steady at 0 for over a month but my nitrate hovers between 40 - 50 ppm. I have tried water changes. I have tested with Salifert, Red Sea, and Red Sea Pro nitrate kits and they are all relatively consistent. I think it is coming from a steady die off of sponges that came in with the rock. (slow death...not the obvious immediate die off you get when you receive rock)

My question to everyone is how high is too high for nitrates? The coral do not seem to be bothered by it thus far (approx. 2 weeks). My phosphate is sitting at 0.4 but I don't seem to have much problem with algae. I considered more drastic measures like Nopox dosing. My main concern is that the corals will degrade over time and I will add fish in about 2 months. I worry that this situation will only get worse.

I appreciate any insight the group might have.

-jdewolftx

My

 

[toothybugs]

You have fairly hardy stonies there so you shouldn't have too much hassle with them, but I personally would consider keeping going with the water changes and possibly vinegar for a bit. I'd set a goal to get NO3 down to 5 or lower, preferably under 2.

 

[MondoBongo]

in my personal experience, nitrates above 50ppm start to retard the calcification of stony corals and clams, in some cases even leading to their loss.

this comes from my laziness last summer, of not doing my normal water changes.

your mileage may vary.

 

[CStrickland]

What is your water change amount and frequency?
I'd watch the anemone and the urchins, they might start to act funny at 50ppm, and if they are happy that's a good sign.

 

[daveM100]

Mine stays at 50, no matter what I do. Everything in the tank is thriving so I don't worry about it anymore. Three different types of nems, urchins spawn, just goes to show no two systems are or react the same.

 

[jdewolftx]

I change my water about every 2 to 3 weeks and thus far I have been doing 25 gallon water changes. I have an Apex system and an ato setup to try to monitor and keep things stable.

So far the nems and sea urchins seem to be fine. I have one top hat urchin that has some polyps on his head. These polyps have grown quite a bit in the last month. I recently found 5 baby black / purple spiny urchins. They are also growing like weeds. So much so in fact, I am considering prying a few out and taking them to my LFS.

I too think that my eventual goal should be to get down to sub 10 ppm. I eventually want to add a clam and some acropora frags (~ 1 year after tank start). I just cannot see doing that with 30 or 40 ppm nitrate.

If I were to dose slowly with some vodka or vinegar, would I be able to back away from it or will I be stuck dosing forever? I have a nice doser (GHL 2). But I don't like the idea of always dosing carbon if I don't have to.

Thanks again for the quick responses.

-jdewolftx

 

[Fallling]

IME to reduce nitrates, you're better off doing a couple 50% changes over a week vs many small water changes (make sure temp, alk, salinity, and ph match). If your phosphate is actually 0.4 (not 0.04), that's also really high and can lead to calcification problems in stonies corals (and also browned out colors). High nitrates will also cause color and growth issues with stonies. While you might not have algae problems right now, it can spring up awfully fast.

I'd work on getting the nitrates down a bit and also the phosphate. With that said, if animals seem to be doing ok, I wouldn't stress about it too much, but just be aware of potential problems. I personally shoot for under 10ppm nitrates and 0.1 phosphate.

Also, with the urchins, that's a lot for a tank that size. They are voracious grazers and will start chomping coralline if there's not enough algae to graze on, especially as they get bigger. They sound like rock boring urchins like have, and they grow fast. Mine started out dime size (hitchhikers) and are now almost softball size little over a year later.

 

[toothybugs]

"Always" dosing carbon? I just toss about a cup in to my ATO reservoir and let it go! Of course, spend a week or two building up your tank to dosing, then have at it.

 

[nuxx]

I'm shooting for 0-5 ppm on a mixed reef.

IMO 50 is a little high for some coral. Won't bother your fish in the slightest.

 

[Mcgeezer]

Less then 5 ppm is ideal. You really need to do several large water changes over a 2 week period...probably 50% a week for 2 weeks. That way you turn over your entire system. You will likely see a drastic difference in your test results after doing so.

I'd also employ a small refugium in your sump. If you don't have a section to use as one...then simply build one from thin acrylic ( will cost like $10 at lowes...it's in the glass section) simply super glue it together and place it in an open section of your sump. I keep fern caulerpa in it along with red mangrove pods that I find at the beach in the winter time. I find that it naturally keeps nitrates down since nitrate is a natural nutrient used up by the macro algae, along with picking up any phosphate that your GFO may miss.