Nitrate problems.

[alvin]

Here is some background:

Tank 90 gal 105 total
200 lb live rock, LPS, zoos, mushrooms, a leather.
Fish are yellow tang, gold spotted rabbit, two clowns and 6 damsels
Trying SPS.

I cannot get my nitrates below 80 ppm no matter what I do. Water changes are 20 gallon a week of ro water. Recirculating at 700 gph. 4 hydor 900 flowing at different times and shut off when light are out. Lights are 260 watt PC 460 nm from 6 am 10 pm, 260 watt PC 10k from 10-8 and 350 mh from 2-6.

No sponges, sock filter changed daily. 15 watt UV, octopus cone skimmer, skimz nitrate reactor filled with bio media and seachem de-nitrate. One bag of carbon in the sump.

Everyone is fine except the SPS. They are all bleaching. Nems seem OK, but have shrunk a little. I'm lost. Any help is appreciated.

 

[CHSUB]

how are you running the denitrate? if used improperly they can be a nitrate factory.

 

[SushiGirl]

Larger water changes to get it down, then see if it stays down or goes back up.

 

[kissman]

if nitrates are 80 and you want them to lower do a 50% water change then they will be at 40. I did them every few days till I got mine to 20ppm then started dosing vinegar. It takes big water changes with RO/DI water to get them down.

 

[alvin]

how are you running the denitrate? if used improperly they can be a nitrate factory.

I run it with a circulation pump in the main chamber with an output of less than a gph. It's mostly just trickling into the sump. The circulation pump is integrated into the system, so I assumed it was sized correctly.

 

[alvin]

Larger water changes to get it down, then see if it stays down or goes back up.

We tried that, but they just bump back up. I then removed every sponge filter from the tank (overflow, sump block, return pump ) figuring that would help. No luck.

I forgot to post my other readings. Ammonia 0, nitrite 0, calcium 450, ph 7.8 and salinity around 1.020. Alkalinity is around 10, but I've found my test difficult to use so I don't really trust it.

 

[alvin]

if nitrates are 80 and you want them to lower do a 50% water change then they will be at 40. I did them every few days till I got mine to 20ppm then started dosing vinegar. It takes big water changes with RO/DI water to get them down.

I've read about vinegar and vodka dosing. Might have to try it if nothing else works. What's frustrating is I've been doing this for 15 years! I figured that was long enough to get into sps, but I'm running into this little and expensive roadblock. Probably lost 300 in sps in the last month. My first one did great for 3 months, then boom, one day all white. Now the others are bleaching too.

 

[CHSUB]

I run it with a circulation pump in the main chamber with an output of less than a gph. It's mostly just trickling into the sump. The circulation pump is integrated into the system, so I assumed it was sized correctly.

what type of media are you using and have you tested the effluent. i have found that some de-No3 if set improperly will stop denitrifying at no2. causing the cycle to start again resulting in higher no3

 

[Bruno3047]

Obviously your denitrator is not working properly. A properly working denitrator would have your nitrates between 0-5, without fail. You need to find out where you're going wrong with that and that will solve your problem.