DIY hose for changes
I made a hose out of 1/2" clear vinyl tubing with a male hose repair connection on the sink end plus an adapter that mated the faucet threads (after you take the aerator screen off) to the hose threads. (Take the aerator to the hardware store to be sure you get the right adapter threads)
At the tank end I put a female hose repair connection, plus a hose shut off valve. That end has a 2 suction cup heater holder to hold it in the tank. This hose is about 75' long which can reach from one central bathroom sink to 5 different tanks in different rooms, as well as from each tank to a window. The 2 kitchen tanks are on separate hoses.
To drain a tank, I set the suction cup end in the tank at the 50% mark and stick the other end out a window after giving it one good suck to get the siphon started. Sometimes I close the top of the tank to help keep the hose in place and I go do something else as it drains. I might be trimming plants in that tank or another, I might clean a canister filter or wipe down tank walls. I might gravel vac that tank or another with a separate gravel cleaning thing into a bucket or out the window, depending on which tank it is.
When the siphon stops, I "chase" all the water out the window, then take that end to the bathroom and hook that end to the faucet and refill.
I stay with it to make sure temp is steady, for it is tricky in summer and winter as our pipes run through the uninsulated attic. Just stand there with your finger in stream of water entering the tank, you can tell and adjust as needed before the fish even notice. I add dechlorinator as the water starts filling.
The hose needs to be cared for properly for the 1/2" clear vinyl is not as strong as the Python tubing. You have to be careful as you roll it up so it does not kink. It's nearly impossible to get a kink out, once it does it kinks there easily and a kink will prevent the drain or refill.
Always drain all water out as you roll it up, I close the shutoff and catch taht last 1/4 cup before it runs onto the carpet. If you don't it gets nasty fast, it may need bleaching occasionally anyhow.
The Q tank has a separate siphon hose and when I refill it I attach the suction cups to the inside of the lid so it does not hang in the tank -- just incase the Q tank is sick I don't want to contaminate by using the hose.
The discus tank has it's own hoses and I do not share any equipment there. Eventually, each tank will have a separate hose, but I have been slow to accumulate them -- it is too hard to store all this stuff.