hi, i am after a decent pump to make water changes easier. e.g use a vac to suck out some of the crap and then suck the pump onto the side (using suckers ) and then pump the water via a tube into the cink. and then from a large bucket on the floor uphill into the tank. can anyone recommend me a decent one that will do the job. tank is a 120L and i replace about 25% of the water 3x a week. i dont know what lph i will need especially to pump a metre up into the tank. help please. oh and where to buy it etc. many thanks guys.