I thought I was doing all the right things

[FrigidHare]

55L tank for one goldfish (biggish though) I partially change the water once a fortnight, use water treatment & greenaway, but the tank still gets green ( the gravel is turning greeny and the window cleaner thing was covered in green stuff). It is a fairly new tank but I had the same problem with the old one (LAC). I took out the plastic plants and rinsed them off, also the balsa wood ornament which is mounted on slate. It is covered in very dark green algae, at least I think it is algae. The tank is in a darkish corner of the kitchen, but I don't really have anywhere else to house it to be honest, and prefer it in there so that when I clean it out, I don't have to worry about the floor too much as it's tiles, opposed to everywhere else in the house which is carpeted.

I don't do the ph test thing, but should I? Is there anything else? Have had Mr Fish for going on 9 years and I am a lot more vigilant (alarm on computer is set to remind me every 2 weeks) about cleaning him of late so it isn't neglect.

The excess algae is almost certainly down to water quality. I would test the nitrAte level, I would expect it to be quite high. A water change once a fortnight is not enough really, I would be doing one twice a week with a goldfish in a tank that size. Goldfish really need a much larger tank. Mr Fish is doing well but he'd do better with more space.

How long has the tank been set up?

This is about goldfish tanks and this is about algae.

Thank you for your reply. I was going off the advice given to me by the local fish shop, (recommended & everyone I know gets their fish from there) will get a testing kit, and also read your links.