Stupid Beginner Question

[*blacksnapemoor*]

ye i suggest that you try and balence out the temp as best as possible so the fish dont get shock which can cause them serious damage even death so ye just try match best you can probley wont happen if your careful

 

[Lizzie71]

I did a water change this evening. The tank is small so a 25% change is just one bucket

I used one boiled kettle and the rest tap water, which seemed to balance out nicely, and my little platys seemed happy enough! The temperature was 27 degrees before and 26 degrees after so I wasn't far off.

 

[Chrispixx]

Usually if the water temp difference is within 3 or 4 degrees it won't make too much of a difference.

But i was always told the difference should be to the warmer side this is what i was taught, so i set the faucet 2 degrees or so warmer then go. I was told putting cold water into a warm tank will shock the fish ( sarahp - not sure how that works for you), not to mention causing the heater to work harder driving up the electric bill.

I never use water from the hot tap, its a fact that the water that comes out the hot water tap will sometimes, perhaps even usually, contain more lead and copper than water from the cold tap.

Usually it will... unless you have pure water like me. So i have no problem mixing hot & cold from the tap straight into the tank(s).
Which is what I'm going to do right now.

 

[MHunt]

Yeah, you should generally try and match the temp of the water you're adding to that of the tank, I tend to do it by hand, mixing the hot and cold from the tap till it feels right, then adding the dechlor before it goes into the tank. There are reasons for adding cooler or warmer water to the tank at water changes but these are normally to do with breeding and getting fish to spawn. Normally you should match the water temp.

 

[andywg]

Usually if the water temp difference is within 3 or 4 degrees it won't make too much of a difference.

But i was always told the difference should be to the warmer side this is what i was taught, so i set the faucet 2 degrees or so warmer then go. I was told putting cold water into a warm tank will shock the fish ( sarahp - not sure how that works for you), not to mention causing the heater to work harder driving up the electric bill.

Cold water will not shock the fish and stimulates many fish to spawn. In the wild there are a number of things (rainfall and the spring melting of ice in river sources) that cause the water to cool.

Many people with large tanks just hook a hose up to the cold tank and fill from there. If your tank is at 24 degrees C and you are in the middle of a Scottish winter (7 degree C from the mains) then the maximum theoretical drop in temperature possible is around 2.4 degrees (I worked out the eact numbers in a post ages ago). That assumes all the water is put in instantly and no heating affect can occur (normally the heater and heat from lights and pumps will heat the coller water on its way so that the effect of the cold is lessened).

I often change up to 40% with only cold water going in and experience nothing more than a couple of degrees difference. As noted above, most fish swim into the cooler stream of water.

If you are changing 50% and more then heating will become necessary, but for most 10-25% changes it is not necessary at all to heat the water.