I'm planning on getting a new tank soon since mine is really tiny right now, but i wanted some people's advice on the best ways to change water in your tank, since i don't know where to go to find this sort of information.

ok, so if you want to do a 50% water change, is it ok to pour the water out directly from the tank while the fish is still in it? or do you first take out the fish and then take the water out? and also, is there a way to clean the bits of food or poop that sunk down to the bottom of the tank (mixed with the gravel) without doing a 100% water change?

for the food that has sunk to the bottom you just need to buy a tank vac. they're fairly cheap and easy to use. they work with a syphon system, you just need a long tube and a bucket. suck on the end of the tube until the water is flowing out the other end and place it above the gravel to suck up all the poop!

this also aids in water changes because then all you have to do is add water as some has already been removed

as for the rest of your questions i don't know enough to answer them sorry!

or if you find that too gross you can buy one :

Like this

Hey Shu*ster

When I do my water changes I use was Water Siphon to clean out the gunk for the bottom..it worksreally swell...once you understand how to use it...he he he..took me a day or so but i got it. Also when i do my water changes I keep my fish in because the siphon sucks out all the gunk and the water at the same time...but you have to watch out for the little guys and gals. Otherwise you could suck them up...and that woouldnt be pleasent...

PS With a Siphon you dont need to suck on it because...yeah you want fish poo in your mouth? Idont think so...you just need to follow the directions..I never had to suck on my siphon...

when i clean my tanks i open a window and siphon the water on to my yard. this way i do not need to carry any water in pails :goldfish

I used to take my fish out when I 'Vacumed' the tank but this upset them. I now do it with them in and they are cool about this. You have to be careful though that you dont accidentally get them caught up in the process.
If you ever do need to take your fish out for any reason, it is important to put them in some tank water not new water as this will reduce the stress of the whole thing. If you have an undergravel filter you are probably best to take them out when you clean under the plastic filter base as there will be alot of gunk stored there which when disturbed will release alot of bacteria into the tank water very suddenly which is not good for your fishes health. Alot of members of KGW tend not to be in favour of undergravel filters for this reason.
Also the same could be said if your tank is really dirty.
If you get a big tank you will find that it will be too heavy to lift up and pour out any water. To do a water change without vacuming, you would have to take water out with a jug or something.

What a great idea from Bill- syphon out a window if you are near one!