ok i have figured both my problems out i was having trouble vacuuming my waste it goes half way up the vac then sinks back down, so i cut some hose pipe about 5 metres and use the hose pipe to vacuum my waste the other end goes out of my window and into an outside drain. this is alot more powerful and more accurate for vacuuming waste, it sucks it straight up no problem.
Second problem is what i started this thread about suck water out of the bucket and into the tank i pull a small waist high cuboard next to my tank and put my 25l jerry can on it then stick my intake hose in and turn my filter on and it sucks it straight into the tank, then i turn it off when it gets close to the bottom and swap the jerry can for a full one then keep on repeating until im done. today i changed 100 litres with minimal effort, especialy since i saved on carrying buckets when emptying the tank, when the hose emptys straight into the drain.
it was a bit tricky at first but i think next time i will have it perfect, certainly saves alot of lifting. hope this helps some body