Nitrate spike.

Hey gang. My daughter has a 36g cycled tank. It's housing 6 guppies and 5 sterbaI cories. They have all been in the tank for over a month now. I have been testing the water once a week and doing weekly water changes by vacuuming the gravel. I did one last night. Checked the water today and my nitrates were 20-40ppm. I have never seen them this high ever. I feed once a day. The fish all act fine. Just wondering what could be causing the spike. She doesn't have any live plants or anything to consume some of the nitrates but water changes. Any thoughts on what could be causing this?

 

Could be a false reading. Did you retest?

 

Well a nitrate spike is better than a nitrite spike. You don't have snails or any small creatures that could have died and went unnoticed? Do you have gravel substrate or sand? If it's gravel, how well do you vacuum the gravel. Do you get beneath the surface or just the top? How often do you do water changes?

 

I did retest and it was the same. No snails or small creatures. Gravel I feel like I do a thorough job cleaning it. I move all decor. I don't get every square inch to the bottom. But it's noticably cleaner when finished.

 

I did retest and it was the same. No snails or small creatures. Gravel I feel like I do a thorough job cleaning it. I move all decor. I don't get every square inch to the bottom. But it's noticably cleaner when finished.

How often do you do water changes? How much water do you replace?

 

Once a week. About 10gallons at a time

 

Once a week. About 10gallons at a time

Hmm, that should be plenty since you don't have a lot of fish in there.

 

Has me baffled as well. Doing at least 50% change now. Will hopefully right the ship. We will see.

 

Have you tested your tap water?

 

Yes 0ppm. Unless we had a spike yesterday when I was filling for some unknown reason. I am thoroughly confused