Nitrate Reduction - what would you do?

kkgaskin90 · Aug 25, 2015

My tank chemistry was going quite well, until it suddenly wasn't. After going crazy trying to figure out why, I discovered the water I was buying from the LFS to do my water changes was testing 20 Nitrates on the saltwater and 15 TDS on the RODI straight from the holding tank. So voila. Fast forward 4 weeks. I've been doing 15g changes every week with new water that tests perfect and still can't get my Nitrates to budge from 20. 75g tank 20g sump. I replaced my sump last week and upgraded my skimmer.
SO, from here, what would be your next move? Big water change? How big? Media reactor?

shornik · Aug 25, 2015

I've been dosing vodka and it has worked great for me, it takes a while before you can get the Nitrates down to where you want them but once there it's pretty stable.

Randy Holmes-Farley · Aug 25, 2015

I'm wondering if you have a test kit error. About the only way some RO/DI could read 20 ppm nitrate at 15 ppm TDS is it is was pure sodium nitrate in the water, which seems quite unlikely.

Couple that with 20 ppm in the tank not budging makes me think possible testing problem.

I'd test something else for nitrate, like another tank or some good RO/DI.

As to lowering nitrate, there are lots of ways that I describe here:

Nitrate in the Reef Aquarium - REEFEDITION

kkgaskin90 · Aug 25, 2015

Randy Holmes-Farley said:
I'm wondering if you have a test kit error. About the only way some RO/DI could read 20 ppm nitrate at 15 ppm TDS is it is was pure sodium nitrate in the water, which seems quite unlikely.

Couple that with 20 ppm in the tank not budging makes me think possible testing problem.

I'd test something else for nitrate, like another tank or some good RO/DI.

As to lowering nitrate, there are lots of ways that I describe here:

Nitrate in the Reef Aquarium - REEFEDITION

The mixed saltwater tested 20 Nitrates while the RODI fresh water tested 15 TDS. Two different holding tanks at the same LFS, if that makes a difference. Sorry that wasn't clear.

Randy Holmes-Farley · Aug 25, 2015

So you have tested new salt water with this kit and get a low value?

Assuming so, there are many approaches. I use vinegar dosing, skimming, lots of live rock, and growing macroalgae.

kkgaskin90 · Aug 25, 2015

Randy Holmes-Farley said:
So you have tested new salt water with this kit and get a low value?

Assuming so, there are many approaches. I use vinegar dosing, skimming, lots of live rock, and growing macroalgae.

I've got 1:30 left on the test, but so far it's 0.

I just got a mongo skimmer for my size tank, so I'm thinking vodka dosing might be the way to go. How long would it be until nitrates decreased if I decided to dose?

kkgaskin90 · Aug 25, 2015

0 Nitrates on saltwater from the new source

Randy Holmes-Farley · Aug 26, 2015

kkgaskin90 said:
I've got 1:30 left on the test, but so far it's 0.

I just got a mongo skimmer for my size tank, so I'm thinking vodka dosing might be the way to go. How long would it be until nitrates decreased if I decided to dose?

Depends on how fast you ramp up the dose, but it isn't an especially fast process. Weeks. But that is not usually a problem.

kkgaskin90 · Aug 26, 2015

Randy Holmes-Farley said:
Depends on how fast you ramp up the dose, but it isn't an especially fast process. Weeks. But that is not usually a problem.

Ok-I won't be creating a dangerously high nitrate environment in those weeks as I up the dose, correct?