I have had a letter from the electric company, advising that they are going to cut off my electric supply due to maitenence if my area... I have 3 6ft tanks, eacj with loads of fish sum big sum small. the cold waters will live, but the bigger breeds may have trouble as the obviously consume more oxygen.. heat wise and oxygen wise im really worried for... heat i can possibly solve with 2 ltr plastic bottles and plce in the tank.. But wot about oxygen, ive learned that oxygen tablet are crap. and if i blow into the tank, that would just make the tank have more Co2.. i cannot find a battery powerd pump anywhere, and i have`nt got a power generator.. and it happeneing this wenesday. So im kinda stressed at the moment.. Any advice on a making a pump?? thx