[mobius981]

To Be Or Not To Be: Here is the question:

Whether tis better(nobler in the mind) to outgas CO2 by allowing new tank water to sit overnight, thus raising Ph to current tank level and avoiding Ph swing from 7.4 to 8.2, Or to heat new tank water to current tank temperature by judicious use of hot water tap, thereby avoiding 68 (room temp) to 80 degrees F temperature swing?

It has to be one or the other, i can't see how to do both. This has to do with 50% water changes while cycling (or really, any other time and any other amount).

Please weigh in. Maybe a nap is in order (lol).

5 gallon tank with 3.75 gallons of water. So a two gallon water change essentially, when I do 50%.

 

[aselvarial]

I have a big 5 gallon bucket and a small heater. I just fill it up the night before i want to change it, plop the heater in, and it comes up to temperature and lets gas out at the same time. But you need less. What I did, when I had a 2.5 gallon tank though, is fill up a gallon, let it sit 24 hours, and the next day heat half of the gallon in the microwave for 3 minutes. Mixed that with the rest of the gallon that was cold, and it usually brought it right up to 80F. Make sure to mix well to avoid hot/cold spots. It worked well. If you don't/can't microwave, heat half gallon on the stove up until it feels hot but isn't boiling, and then mix with cold. That way you get no co2 and proper PH, and temp matched water.

 

[mobius981]

Thank you, thank you!!! I have thermometers to check,and I think I can do the math. That works!!! Just a matter of making it routine, I would hate to shock fish, and I was stuck. Sounds like you have been there, done that. Might be worth it for me to get another heater then. For tank changes.

 

[fidget]

I've read that pH shock is worse but I haven't had a problem with it. The difference in pH doesn't seem to bother my fish.
I match the temp and change the water slowly.
You can always add back half the water, wait 20 minutes (to give him time to acclimate) then add the rest.

 

[aselvarial]

Thank you, thank you!!! I have thermometers to check,and I think I can do the math. That works!!! Just a matter of making it routine, I would hate to shock fish, and I was stuck. Sounds like you have been there, done that. Might be worth it for me to get another heater then. For tank changes.

You're welcome. It doesn't take long. I usually plopped the half gallon in the microwave while I pulled out a gallon of water from the tank and cleaned the bottom. By the time I was done, the water was ready to be mixed. Start with 2 minutes and work your way up. Having to wait for it to cool back down is a pain. And honestly, in a smaller tank, another heater just to warm up the water is cool, but probably not necessary. Once you get it down, it doesn't add hardly any time at all.