Tank Cleaning

I clean the glass in the tank every week when I do the water change, except the glass at the back of the tank which I have always left more or less untouched so that the plecs have a good supply of algae. You can't see any algae when the lights are on in the tank because of the backing paper, but when the tank is dark and the room lights on, it's obvious there is quite a build up.

If I just leave it would this have any effect on the water quality or the health of the tank, and is it better to keep cleaning it as I do the rest of the glass?

Well, im not sure this will really answer the question but I clean mine off when there is a build up. In the cichlid tank they graze on algae all day on the rocks but never touch the glass..including the 3 bristlenose that are in there. I think they have so much food elsewhere they don't bother.
I'm sure it wouldn't affect the water quality but i think it gets to a stage of just looking unsightly

Looks like I'd better get the Jiff out then MC

AFAIK algae is more of an aesthetic issue than a water quality thing. If it does become a significant prolem, then I can highly recommend Otos, Diana. Since I added four of them to my 90L tank, it's just spotless - they've even cleaned off the brown algae that was growing on the Java Fern. So I'll be adding four of them to my 165L tank also as that has the coating of green algae you mention so I'm hoping they'll work their magic there also.

I too tend to just clean off the front and sides of the larger tank as I can't actually reach the back of it. Although IMO a light coating of algae actually gives a tank a more "natural" look as sometimes if a tank is too clean, it can look almost sterile. No fear of that happening in my goldie tanks, that's for sure! :lol:

I dont know much about oto's Mary, but am not sure I have room for them. I have a couple of mollies waiting to go in the big tank.

Thanks for the suggestion though, I might have a bit of a read up on them!