I can't seem to shake off the aggresive whitespot infection in my tank ,I have killed off the good bacteria in my undergravel filter so i am reluctant to treat any more , is there any way to slow the spraead of the disease while i let my tank recover ?

What did you use so far? The medications I used to treat ick didn't kill off good bacteria (I use aquarium salt and Aquari-sol which has copper sulfate). Ick develops faster in warmer water so cooling things down will slow things down but also slow down the fish's metabolism/resistance and the good bacteria. What is the tank temperature?

I don't relly know how warm my tank is as it does not have a working thermometer, I think it is about 26 degrees ish ,but it remains constantly warm ,without a heater.
I have been using a powerful 48 hour treatment that treats many other ailments as well,it is just call WSP anti whitespot, but it turns the tank blue when i put it in. and it is usually very effective ,but since the tank turned cloud I an reluctant to treat in case the water quality gets worse.

It might be methylene blue or copper sulfate. The former could kill good bacteria. The tank's sounds warm enough.