Adding Dry Rock to a existing Tank?

[David100]

Im having a bit of a GHA problem and one of my rocks has pally on, Im not a big fan of them and it makes it particularly hard to clean.

Can I just toss out 50% of my rock and put in brand-new dry rock from my LFS? I have BIO Balls in the sump and id still have 50% live rock that would populate my bacteria? WOuld I need to consider anything? Would I cycle again? or have any ammonia issues or Po4 issues to consider?

 

[T-J]

Why not put some dry rock into your sump for a month or so, then pull out the rock from your DT and move the rock from the sump into the DT? That way you won't be losing half of your biofilter.

 

[bushdoc]

As above is better, but you can put some dry rock directly to established DT.
New dry rock will be initially colonized by algae, starting with diatoms and then if you lucky, followed by GHA, so problem with GHA will not be resolved.
I have done that, but with just one or two pieces I needed for something.

 

[TopShelfAquatics]

As Bushdoc mentioned. Adding the new dry rock will not solve your problem. Wether you let it cycle in your sump for a bit before swapping it out, you are not treating the root of the problem. GHA can be quite annoying, but before resorting to removing rocks I would try to find if the problems is nutrient export issues, too much white light or even lack of flow can contribute. Once you fix the cause then if you are still keen on swapping rocks I would let them seed for a bit before doing the swap. If you don't treat first your new rock will be covered in GHA in no time.