Geeman, I'm using a Pond one 02 Plus 4000 35Ltr/min although I will upgrade when I have some cash.
Mark, it is just to accommodate present stock as my bn's are breeding non stop, unfortunately means less space for cory projects until I move some on, the CAS aution would have been ideal but I'm working and cannot get it off.
Intrepidmax (Mark) I see your point about the window and my dad put in a second window to help but it may need looking at again when it gets colder, it's pretty hot in there at the moment, for me anyway but I can open up the window if we get a heat wave.
Rabbit, the air ring is 1.25" pressure pipe from Wicks and all the joints are pressure joints so I didn't use solvents to bond them and more pipes can be easily added to the ring when needed. My dad built the frames for the tanks after watching a fella from a local store building one for a few mins, I couldn't have done it, lol.
Cheers
Gemma