The nitrate levels in our sunsun tank is elevated and we're not entirely sure why. There's no plants ATM (we've purchased a Aquaone 850, and will heavily plant it and swap the fish over then)
We do weekly 50% water changes, the tank has lots of rocks which make it difficult to gravel clean. But yesterday we noticed one of the YoYos lying on his side so we did a full run of tests and found the Ammonia was at .25 the PH was 7.6 and the nitrates were 5.0 and the nitrites were 0.
So we pulled all the rocks out and did a thorough gravel clean, a 80% water change and added stress zyme. Last night the ammonia and nitrites were all 0, Ph was 7 but the Nitrates were still 5.0 and it hasn't changed this morning.
The fish all seem happy, and the water looks beautifully clear.
The tank is 160ltrs, stocking rates are 2 angels, 2 yoyos, 2 kribs, a GAE, and a rainbow shark, all fish are adolescents. The filters is a Eheim 2215 and the built in filter does 900ltrs/hr.
Does anyone have any ideas? are we missing something?
Cheers all.