I have 2 vacuum hoses that attach to my taps for my 29 gallon tanks. I don't use all cold water, I try to take the edge off it by adding warm. I find I have to keep an eye on the thermometer as on occasion the temp was creeping up too high so had to adjust accordingly. My 10 gallon I just add a mixture of warm and cold, again just to take the edge of the cold.
I use decholinator since our water has chlorine it it (didn't forget about the chloramines Alan!). Plus there are copper pipes in my place. I emailed the company about the dechlorinator and they said it was for all that kind of "stuff".
Caper