I have been battling issues with brown algae for a couple of weeks now and it is really driving me mad. For the record this is an established tank. I test the tank weekly and perform a water change as a maintenance duty. To memory recent changes to the tank, a few weeks ago I pulled out two of the four live plants. A larger Java Fern and a smaller Anubias, this left a smaller Java Fern and another plant. On the water change last week I did a light scrub of the acrylic walls of the tank on the hot spots and the decorations as well as needed. I did not remove them from the tank. More important after the water change I did muck with the filter. Although I did not remove or touch the main filter, I did remove the white Fluval sponge filter I have been using to capture and control the flow of the outgoing water. In my infinite wisdom I decided to replace the sponge filter which was awful brown and nasty with Fluval ceramic bio media. I know, why did you go and do that? Apart from being disgusting I have no idea, but simple swishy swishy was not working. Why I did not use another sponge, again don't ask. It had been working fine for months and I should have just swapped out for a clean replacement. I have made my bed so now I am trying to work through this without making it a bigger nightmare.
It is not a Fluval filtration system, I am using the simple Whisper 10i that came with the Marineland 5. I went with the Fluval white sponge as a baffle/capture some extra good bacteria remedy.
The API tests showed Ammonia 0, Nitrate 5, Nitrite 0. The pH is awful but it is consistently awful since day one so..
I run the light around 8 hours a day, the tank is in a room that is not getting much natural light and what little it does is pretty dim. Water is kept at 80.
I am pretty sure my mucking with the filter media is causing this but any suggestions, comments, concerns, complaints.. I would really appreciate constructive criticism peppered with some advice.. so would the fish, the snail and the ghost shrimp the latter two are useless in this.