High nitrate after water change?

[michaelabellz]

So just 2 days ago i preformed a water change as my nitrate levels read at a high 25. I’d say I did about a 45% water change with r.o water. But when I checked again today my nitrate readings are exactly the same? The only thing I can think of is doing another water change, but i don’t want to over stress my live stock as I had just did one? Anyone have any suggestions? Thank you.

 

[Randy Holmes-Farley Verified Community Expert]

So just 2 days ago i preformed a water change as my nitrate levels read at a high 25. I’d say I did about a 45% water change with r.o water. But when I checked again today my nitrate readings are exactly the same? The only thing I can think of is doing another water change, but i don’t want to over stress my live stock as I had just did one? Anyone have any suggestions? Thank you.

Most nitrate kits aren't especially precise. Not sure what one you are using, but trying to see a factor of 2 is tricky with many kits.

 

[michaelabellz]

Most nitrate kits aren't especially precise. Not sure what one you are using, but trying to see a factor of 2 is tricky with many kits.

I use the salifert test kit. Is there any other nitrate kit that’s more precise that you know of?

 

[Saltyreef]

It may be your RO water...
An RO membrane will not remove 100% of nitrates and if the source water has a lot you may be getting some carry over to your tank.

This can happen more often with LFS and machine bought RO as most of the time theyre not replacing filters as needed.

 

[Saltyreef]

I use the salifert test kit. Is there any other nitrate kit that’s more precise that you know of?

For low range nitrate i like red sea. Salifert is good too but the range isnt as precise.

 

[michaelabellz]

For low range nitrate i like red sea. Salifert is good too but the range isnt as precise.

Okay thank you so much for the help. I’ll definitely look into the Red Sea test kit.