My 150 has been running for 2 months now and had been cycled for well over a month. 3 Days ago I noticed that my black aro was breathing weird so I checked everything and noticed that the nitrites had spiked. The only difference in the tank is that I took off a Fluval 404 that had been running and replaced it with a second FX5. All of the media from the 404 was transferred to the new FX5. The thing that I can think of is that I had a polishing pad in each of the filters that were after 4 days. This may have been constricting the flow over the bio media. Any other ideas why this would happen?
Eric
Eric
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