Old tank water compared to new tank water

[lionfishlover]

I am setting up a new tank as some of you know, the problem is that the water test results between the old tank and the new tank are quite different. My new tank is GH>16, pH 8, KH 20, while my old tank is GH >16, pH 7, KH 3. The only difference to the water is that the water in the old tank went through a brita filter before it went into the tank.

If once the new tank is cycled i do water changes using water through the brita filter until the water test results are close enough to the old tanks results to put the fish in. How much higher could the results be so i could put the fish in without causing them harm?

Sorry if i dont make much sence with this, i know what i mean but i am having trouble explaining it, but hopefully you will understand.

Cheers Scott

 

[sylvia]

I'd say you should match it up exactly to reduce stress...
In actual fact just aclimatising them very slowly and carefuly would be enough.
Any reasonable steady pH should be ok once they are acclimatised but one that fluctuates will kill them. I'd try to match it as closely as possible and then keep it that way.
I'd suggest you do a very large water change now though - rather than wait for the tank to cycle first. Then you'll have more chance later on to make sure the pH has matched up before adding fish.

 

[lionfishlover]

To match the water exactly to the other tanks levels i would have to change probably 90% of the water, would you advise doing several smaller water changes, ie 3 or 4 of 30%, several days apart, rather then doing one extremely large water change.

Also will this affect the fishless cycle that i am doing?

Cheers, Scott

 

[sylvia]

It's up to you which way you do it - if you've only just started cycling (yes it will effect the cycle slightly BTW, but not substantialy) you may as well do the full 90% change. If, on the other hand, you are quite into the cycling, you may not want to risk a longer cycle and do several small changes instead. Either would work.

 

[lionfishlover]

Okay, well, cheers for the advise, i will do several smaller water changes a couple of days apart, as time is an issue with the cycle, as the fish are in another tank at the moment which has cycling problems, and want to get the new tank cycling properly before i put them in the new tank.

Cheers, Scott