I think I will put another inline filter on it, better safe than sorry hey! The inside of the tank was really clean, I'm thinking it isn't the original one. I've just had her running, sat there for 15 20 minutes and was absolutely fine then sat it at 2000 to 2500 and again was fine, a few flutters but it definitely didn't stop as it has done before. The fan seems to be temperamental as it comes on at low temperatures as well as high. So it seems that it only wants to stop when actually driving.