I use a homemade siphon that I made with airline tubing and a couple of chopsticks-twist-tied together- to make the airline tubing ridged-my thumb functions as the control valve..
I siphon into a 1gal white ice cream bucket and use a flashlight under it to look for the fry I may have siphoned out by accident and you will....it just happens and usually no harm is done to them...
I use my homemade siphon and suck them back up in the tip and place them back in the tank or an eyedropper all depending on how big they are....usually by the time they are two weeks old mine are too big and I have to use a net...but generally at that age they don't get sucked up when I clean.......
I replace the water with the siphon and the bucket by using gravity...I have hooks over my tanks that I hang the bucket from and clips I use to secure the tubing to the bucket and the tank and let the like temp dechlorinated water flow back in the tank by gravity....
Here are a couple of pic to give you a better idea of what I made...disregard the duct tape on the end of tubing.....