Well I bit the bullet today and finally cleaned out my fish tank.
I had read somewhere that you should just leave it be during the cycling process, rather than risk disturbing the developing bacteria colonies by mucking about with their home (the filter).
But it has been 5 or 6 weeks since I put the fish in, and the tank does have brown algae in it, and I had a suspicion that the filter may not be working as efficiently as it should.
Also, I have various camping trips planned over the next few weeks, and didn’t want to leave cleaning the tank until afterwards – which means doing it well in advance so as to give me time to help the tank recover from any blips caused by mucking about with the filter colony.
Anyway. I’ve done it.
The filter was absolutely full of brown stuff, I assume this is brown algae as there was an algae bloom over other parts of the tank as well. I haven’t scrubbed everything very thoroughly as I didn’t want to stress out the fish too much all in one hit, but I’ve given the filter a good rinse (in a bucket of water taken out of the aquarium, so as not to kill of the bacteria by washing them in chlorinated water!) and wiped over the surfaces where there was visible algae. Plus, changed some water and hoovered up some debris with the gravel siphon jobby.
The tank looks a bit nicer, the filter seems to be filtering away and the fish came out to play once I’d put their tank back together again. All in all, hooray!
(Although I will check things carefully over the next couple of days in case anything horrible has happened to my bacteria colony…)