Transferring Fish To Tank With High Ph

My fish are in a cramped 10G with a pH of 7.4. I set up a 29G and tested the pH and my tap-- they're both 8.4, which is odd because I use tap in my 10G. Maybe my driftwood is lowering the pH. Anyway, I was going to replace my water in the 29G with bottled spring water with a pH of 7.4, but don't want to have to take out ALL the water. How much can I get away with leaving in there? Half the tank?

Also, how many hours should I spend acclimating the fish if the pH of the 29G is say 7.9 (versus 7.4 in the 10G)?

 

Just do an acclimation like what you would do when you bring new fish home from the store. Add a little tank water to the bag every 15 minutes or so until most of the water is yours and the fish have been able to slowly adjust to the new parameters. Then net them out and release them.

If I were you I would not start mixing in different types of water to try to change pH until you know more about the chemistry of your water. A stable pH is more important. How long has the new tank been set up?

 

A 1 whole point increase in pH won't shock and kill them? I've read some conflicting info..

It's been set up 5 days, and I'm going to add sand from an established aquarium, then make sure it cycles before I transfer them.

 

That's why you need to acclimate them slowly by adding small amounts of the new water to the container at a time. This allows their bodies to adapt.

 

Ok, good to know. Thanks!