How long do your FE (2kg) last? I seem to going thru gas like theres no tomorrow. This is the 3rd FE I 've had since the tank was set up in March. The 1st went in about 6/8 week. When installing the 2nd one I checked all the tubing and connections and found no leaks. This next one again lasted about 8 weeks. Again checked all the pipework and no leaks found. Today just looked at the guage and it seems that this one is now nearly empty. That's 3 Fes in 4 months - why am I using so much? Drop checkers (using 4dkh) never go beyound light green and fish are acting normally.