Temperature difference during w/c

[brandy]

I have a large central storage barrel that I use to age water for all of my tanks. I normally keep the water in the barrel at 84 degrees, which is the same as my tanks. My problem comes when I occasionally need to raise the temperature in one tank, but I cannot raise the temp in my storage barrel because it is used for multiple tanks. My question is, how much temperature variation is okay?

As an example, I currently have one tank at 91 degrees (mild case of hex is suspected). When I do w/c on this tank, I first drain the tank to 50%. I then fill the tank to about 65%, wait awhile, then fill to 85%, wait, then to 100%. (I wait so that the heater can catch up between fillings) When I am done with w/c, tank temperature is 88 degrees. Will this harm the fish?

[RyanH]

I've never seen any noticeable affects on my fish from a three or four degree drop in water temperature. I think you'll be fine.

[Anonapersona]

If you simply added the 84 degree water all at once the tank ought to be at 87.5 (0.5x84)+(0.5x91) = 87.5
so the careful method doesn't seem to help much.

How about increasing the storage tank to 86 temporarily? The other tanks would see a short term 1 degree increase at water change and the Q tank would go to 88.5 which is a tiny bit closer to 91.

[Willie]

All my water changes are at cooler temperatures. Five degrees cooler is normal, 7 - 9 degrees cooler is not uncommon. Never noticed any problem with the fish.

Willie

[brandy]

Thanks for the input. Doing w/c this way didn't seem to bother them, but I just wanted to make sure it was okay.

[FarWaters]

I used to heat the water in my holding tanks, but without filtration I was cleaning them pretty often, which is a hassle the way they are set up. I then tried aging the water without heaters in the tanks and found cleaning not needed as often due to less bacteria growth. I agitate the water with airstones, but still not the same as filtration. Point being that I agree with the above posts, I haven't seen any negative effects on the fish, and the temp change isn't instant, it takes a few minutes to fill the tanks, so I don't worry too much about shocking the fish. Good Luck-

[brandy]

Wow, that would be nice if I didn't need to heat holding tanks. Unfortunately, mine are in my basement. Winter temperature down there may drop to 60 degrees. Oh well, I guess I'll keep heaters in mine.

[jeep]

I don't heat my storage water even in the winter.

My water mat drop as low as 60, but if I on'y change 30-40%, the drop in temp is not that drastic.

I just do more smaller changes :)

Now if you're treating for hex then I would definately heat the water...