water change

Another thought crossed my mind. This is from the really old days. When you do water changes, you raise the level in the tank. If you go above where the glass meets the controller on your heater, and there is a break or crack in the insulation, you may be electrocuting the fish that come too close to the heater. Usually this also is accompanied by eratic swimming behavior by all the occupants of the tank. (it messes with the lateral line).

Joe

50 gallons isn't that bad. I live in Montgomery and age my water a week. I use a Rubbermaid Brute 44 gallon trash bin and run the water through floss and carbon. The reason being that the water here is just full of iron and I pull my water before the softener. After a week of running, the floss is a nice dark orange. As of last Sunday I have not noticed any signs of stressed fish after water changes.

On another train of thought, Winter often is accompanied by ruptured water mains. Have you noticed any street work in your area? Even if it was 3 weeks ago any 'bad' water or sediment is probably still in your hot water heater.

just sounds like your typical micro bubble problem that is pretty common this time of year to me

The tanks I lost fish in are both penguin bio wheels. I had power off and didn't even mess with filters as I didn't want to disturb bacteria levels I figured in a week I would do filters.

Aging that much is tough - true. The alternative I found was to not do water changes when the air temp was sub 32 degrees.

I have heard of "aging" water but to keep 50ish gallons (I have several tanks) would be tough. But I have to do something. As I said I've had tanks for years and this is a first, we'll second in as many months.

Personally, i think test kits are way over rated. If a tank is established and you perform regular maintenance, a test kit isn't really necessary.

One thing to consider - when it is very cold, gases in the water react differently. I dont recall if they are more or less dissolved in the water, but the impact can be very detrimental to your fish. I have seen this in various protomelas and placidochromis sp. If possible, let the water stand over night when it is really cold. Just agitate it with an airstone.