Adding new tank

[rongy]

Hi, I currently have a 65+15 gallon established tank, and I will be getting a new 100+40 gallon tank. I’m looking to combine both tanks (remove one sump) to reduce maintenance. I also plan to remove all sand and go bare bottom on current tank. What’s the safest way to go?

There are two ways that I can think of:
Plan A:

1. Plumb current tank into new sump, and move everything over (can potentially shock the system)
2. Let the system run for a while.
3. Fill 100g display and let it cycle itself (with separate heater and powerhead).
4. Slowly exchange water between the two systems (Maybe 10 gallon per day)
5. Remove sand slowly when the system stabilized

Plan B:

1. Cycle new tank with rock from old system (can only take a few pounds, don’t have a lot of rocks in current system)
2. Slowly move corals over to new system
3. Drain and clean old tank, remove all sands
4. Plumb tank into new tank

I’m leaning toward plan A, as new tank can take really long time to get properly cycled (I have a lot acros, so new system need to be acro ready), but the main goal is to transfer with minimum loss.
Any thought is appreciated.

 

[Snowxcross]

Plan A - Just keep your existing sump filtration in the new sump or any existing rock, etc. and it would be like a huge water change. I cant answer for the sand to no sand though... never done it.

 

[rongy]

Plan A - Just keep your existing sump filtration in the new sump or any existing rock, etc. and it would be like a huge water change. I cant answer for the sand to no sand though... never done it.

How soon should I be exchange water between the DT and the established system? Feels like every water exchange is like doing water change