Nitrate conundrum

Ryan winder · Oct 8, 2018

I’ll lead by saying that my question is concerning nitrates but first I’ll give you all the down and dirty on my tank. It’s a 2 month old 32 Biocube that cycled in about 6 weeks. Doing 15% pwc each week. tunze 9001 skimmer, in tank media basket with filter floss, Purigan, ceramic Biomedia, chemipure blue. In that order

Temp: 79
Salinity: 1.025
Ammonia: 0
Nitrite: 0
Nitrate: 20
Ph : 8.2~
Calc, mag, alk, and phos: unknown ( haven’t tested
Inhabitants: mocha clown, serpent star, and a quarter sized GSP frag, various cuc

On to the nitrate conundrum, nitrates always read 20 ( using API ). It doesn’t matter when I test, before a pwc, 5 minutes after a pwc, 24 hours after, or middle of the week the test appears to always read 20. I even did a 40% change last week and nothing happened. At first I thought it was a problem with the test kit, but I tested my tap water and nitrates were sky high. Then I tested my rodi salt water and nitrates were just above 0. How is it that after a 40% water change with very near 0 rodi water my test still reads 20 and then 7 days later it hasnt gone up or down. Any thoughts or ideas as to what could be causing this. Should I try a different brand of tests, if so what brand do you all recommend?

saltyfilmfolks · Oct 8, 2018

Have you tested ammonia recently?

How did you kick start the cycle.

You did weekly water changes In the weeks right when it was first starting the cycle?

Your rodi is near zero , as in it has no3 , have you tested tds?

Fwiw , the salt should be zero on both

Rakie · Oct 8, 2018

API are not good accurate test kits. Use Salifert.

Ryan winder · Oct 8, 2018

saltyfilmfolks said:
Have you tested ammonia recently?

How did you kick start the cycle.

You did weekly water changes In the weeks right when it was first starting the cycle?

Your rodi is near zero , as in it has no3 , have you tested tds?

Fwiw , the salt should be zero on both

I did a fish in cycle and was doing water changes because of that. ( i won’t do that again) started with dry rock that was not cured. 20 lbs of live sand and 2 bottles of api QuickStart.

Rodi comes from my lfs it didn’t read a perfect zero for nitrates, will test again right now. I have no current means of measuring the tds.

Ammonia and nitrite tested 3 days ago both read zero

Edit: tank has been up for 3 months not 2

Dennis McGrath · Oct 8, 2018

I would bring in a sample to the LFS to see what they come up with.

Ryan winder · Oct 8, 2018

Dennis McGrath said:
I would bring in a sample to the LFS to see what they come up with.

I’ll do that tomorrow before pulling the trigger on the salifert or Red Sea nitrate tests. On a side note 20 doesn’t seem to bad so I’m not really worried about it but I would like to get it under 5 eventually

KrisReef · Oct 8, 2018

Could your rock be leaching nitrates?

Ryan winder · Oct 8, 2018

I knew un-cured dry rock could leach phosphates and I did it anyway to save some money. I haven’t tested phosphates but I wouldn’t be surprised to find high phosphates. The algae bloom following the end of my cycle never really got to bad and it seems to be subsiding so I think phosphates are dropping ( I need to get a test I know I know ) I didn’t realize the rock could leach nitrates or rather ammonia. I did let it sit in a 75% bleach solution for a week to kill off any pests. I skipped the acid bath though

saltyfilmfolks · Oct 8, 2018

KrisReef said:
Could your rock be leaching nitrates?

It would have to be old and , kinda nasty. Prob smell it. Keep in mind no3 is a product of ammoina Ie rot and the cycle.
But yes , it happens

lapin · Oct 8, 2018

If you did a 40% water change with water that had 0 nitrates, you should see a reduction in nitrates; if you tested after the new water mixed with the old. Like stated above if you had ammonia in your water (like from a dead creature) then it would be converted to nitrate. If you did the test a day later that could be why you didnt see a nitrate reduction.
Let us know what the LFS said. Hopefully they wont sell you any snake oil .

)))))

saltyfilmfolks · Oct 8, 2018

I’ll add , the rock would have to have been covers in organics

Ryan winder · Oct 8, 2018

lapin said:
If you did a 40% water change with water that had 0 nitrates, you should see a reduction in nitrates; if you tested after the new water mixed with the old. Like stated above if you had ammonia in your water (like from a dead creature) then it would be converted to nitrate. If you did the test a day later that could be why you didnt see a nitrate reduction.
Let us know what the LFS said. Hopefully they wont sell you any snake oil . )))))

I did lose 2 margarita snails at some point. Not sure when it happened but I found their empty shells. I think the crabs got to them. It may just be that it happened right at the same time as I did my large water change.