[fish keeper 2013]

I was doing a 50% water change and despite my efforts to keep the temperature the same the temperature in the tank rose 3 degrees, will this be very bad for my fish if it happens every week? As the tank is a tropical one I can't leave it out to come to room temperature, because it would be much colder than the tank water. How do I keep the temperature constant? Do I have to resort to using an aquarium heater for the change water? cause I really don't want to do that. Oh yeah, how much of a temperature jump can fish tolerate if the water change is every week?

 

[Tolak]

Mix hot & cold tap, use a thermometer. I fill with a hose & go by feel, so a few degrees up or down is no big deal for all but the most delicate fish. Cooler water changes are a common method used for getting fish to breed, I'll often do a 10% water change every couple days with cold tap water on many breeding projects.

 

[AbbeysDad]

When I was filling from a hose hooked to the sink I spent some time initially with a thermometer and adjusted the hot/cold faucets to get the proper flow and temperature. I then indexed the faucets by making a mark on them with a permanent pen. In this way, week after week all I had to do was open the faucets to the index marks, let the water run for a bit for the pipes to clear and I was good to go... it worked great!

 

[Tolak]

I was thinking on this (yea, I know, dangerous) and ordered a cheap digital thermometer with a probe, since I had to order some heaters. Tape the probe to the outside of the brass faucet, stick the digital part to the wall, let's see how this works. I'm a sucker for hardware.

 

[Byron]

I use my hand to get the tap temp close to the tank water, and then have it slightly cooler. With the exception of some delicate fish that need warmth, adding slightly cooler water is better for the fish. I know some of our members use just the cold water but I do mix in warm so it is not more than perhaps 2-3 degrees cooler. This simulates rainfall in the tropics, and invigorates fish considerably, often inducing spawning the following morning.

Byron.