Question on Transfer livestock to new tank ???

[VarusLOL113]

I running 125gal , gonna downsize to 75gal.
I will buy new live sand, keep same live rock and livestock. So should i re-use old tank water and live rock, let it stabilize first and transfer livestock
or i should bleach live rock, cycle the new tank and transfer livestock later when cycle done ?
Any advice are welcome. Thanks

 

[maxter]

I just move my tank , try to re used the max amount of the old water if is in good quality, re used the rock dnt let the rock out of water to much time , mix new water u going to needed

 

[VarusLOL113]

what if water is not in really good quality ? can i use 40-50% old water and new water. Let the new system run for couple weeks, do wc every week to get every thing in good condition ?

 

[anbosu]

If you're not going to move the fish immediately you can use all new water in your new tank.

 

[sirrealism]

I would be more concerned as to why your water now is not in really good condition. Fix that before you make the change then use your same water. No shock to your livestock this way.

 

[rogergolf66]

Use all new water. Drip acclimate the fish to the new setup after the new tank has cycled.