Why wont my nitrates drop?

No matter what i do my nitrates never will drop below 20ppm....i have did massive water changes (using R/O water)...no results...I have cut back to feeding every other day...no results...i took the bio balls out of my trickle filter...no results...I added a sump with lots of macro...no results...I have a in sump skimmer and a HOB Biggest AquaC Remora with pre surface skimmer....no results.... have 4 powerheads for flow...its a 125g tank I have about 200lbs or so of LR and about 3" of sand....I want to start adding corals to my tank but with my nitrates always lurking at at least 20ppm I just dont wanna chance it...my phosphates are 0...what the heck else can I do..

 

Have you tried a different test kit? 20 nitrates isn't bad at all for most corals.

~Will.

 

Hey Kevin when you figure it out let me know. I am fighting the same thing. I did a major water change this morning and mine are still at 20 too. I am hoping someone on here can tell us what to do.

 

You could try sugar or vodka dosing, I would research and make sure you have decent test kits and appropriate skimmer before going this route.

Heres an article from reefkeeping to start it off:
Vodka Dosing by 'Genetics' and 'Stony_Corals' - Reefkeeping.com

 

Thats alot of live rock try for 1 lb for 1 gal

 

1 lb is the general rule of thumb minimum. there are lots here who are in the 1.5 per gal. the lr is beneficial, i dont think its because of too much rock

 

You could try using some Seachem Purigen, either in a bag, or better yet in a phosban reactor. Others, including myself, have had success eliminating nitrates using this.

 

you have dietris trapped under the rocks and in the sand.
try vaccuming everything real good and flush out the rocks as best as you can. 20 ppm of nitrates wont harm soft and some lps coral, but don't try sps until you can obtain 0 nitrates

 

Could this be nitrate that was absorbed by the LR? Could be slowly leeching out and just needs time to 0 out. Sounds like everything you are doing is on the right track to me.

 

If you are doing massive water changes and your test is the same before and after I would check your test kit too. Unless your salt is high in nitrates or your RO filters need to be changed and are letting some nitrates through, or something like that, then there shouldn't be any way a water change would not reduce your nitrates.
IMO try another brand test kit, a new test kit, or have an LFS doublecheck the results for you.

Maybe try checking your fresh saltwater before doing the water change and see how that measures for nitrates?

Also check your TDS coming out of your RO unit, it should be zero or at the most very low single digits.