Is this a bad idea?

[Aquattro]

Rock in the sump is a good idea, I'll do that.

[PoonTang]

Originally Posted by Aquattro

Rock in the sump is a good idea, I'll do that.

also FWIW everything I have read suggests that transferring over your old water will do nothing to help out the cycle but it will help acclimate the fish a little better.

[Aquattro]

Originally Posted by PoonTang

also FWIW everything I have read suggests that transferring over your old water will do nothing to help out the cycle but it will help acclimate the fish a little better.

Agreed. Bacterial content is insignificant, but chemistry could make transition for the fish easier. I prefer to start with all new water though, as I'm switching salt between tanks.

[sphelps]

Can you just move everything over at once? If you move all the water and rock from the 90 over as well you shouldn't have any cycle problems, it's really the same as just doing a large water change. I've done this a few times with large upgrades without problems.

[Aquattro]

Originally Posted by sphelps

Can you just move everything over at once? If you move all the water and rock from the 90 over as well you shouldn't have any cycle problems, it's really the same as just doing a large water change. I've done this a few times with large upgrades without problems.

The sump won't fit all the rock from the 90, but I'll put 40 or 50 pounds in. The trasfer might take a while as I'm cutting all the corals off the existing rock and remounting to the new rock. So I have to at least keep the 90 3/4 full and just use the water from the sump.

[sphelps]

Originally Posted by Aquattro

The sump won't fit all the rock from the 90, but I'll put 40 or 50 pounds in. The trasfer might take a while as I'm cutting all the corals off the existing rock and remounting to the new rock. So I have to at least keep the 90 3/4 full and just use the water from the sump.

Yeah you should be fine if you can use as much water and rock as possible from the 90. The rock is obviously more important since the water actually has little bacteria in comparison. Is there any reason why you can't use more rock from the 90 and less from the bath tub? Also maybe you can move some of the corals with the attached rock to speed things up and then as time goes on you can do a little rearranging in the 180 when things are 100% stable.
The faster the better IMO and I would spend your time and focus on the 180 rather than trying to maintain the 90 as well.

If it helps pretend your 90 gallon is going to explode in a the next few days and you're not sure exactly when, could be tomorrow or next week. Better work fast!

[Aquattro]

lol, ya, I'm going the exploding 90 route, but I want to build all new structures from the new rock. I suppose I could add some of the existing rock around the bottom, but 50 pounds in the sump should be enough, I think. Coupled with the new rock (about 130 pounds), I should be OK bacteria-wise...I think

[Myka]

If not already mentioned, watch pH closely...turning the skimmer off like that can cause pH to drop quickly enough to cause trouble. If that happens just add a big airstone.

[Aquattro]

Christy, I'm not moving all of the 90 contents in, and in fact wasn't moving much other than 2 rocks with lots of corals growing on it. But, I can add a fair bit to the new sump, just not all. The rock I'm using should be able to catch up quickly, it's been cooking with food source for over a month.

Mindy, yes, O2 content will be something to watch with the skimmer offline...

[Aquattro]

Progress report. 180 full, salt added, the sump is setup with my skimmer, the sump for the 90 got shut down last night. I've added some rock to the new setup (in sump). Waiting for temp to come up.

Meanwhile, back in the 90 (without sump or skimmer), my 3 clams decided this afternoon was a good time to spawn. Currently, I can't see the fish....big sigh, didn't see that one coming. Setting up for a water change now, and going to the expidited move schedule, hopefully starting tomorrow..