30 to 120 tank transfer dKH way off

[Katepete722]

I am in the process of upgrading my biocube 29 to a 120 with a 40 gallon sump. I've got the new tank plumbed and filled with sand and cured live rock in place. Unfortunately the freshly mixed water in the 120 is reading off the charts on my salifert dKH test. My 29 is currently at 8.9 dKH. So I'm not sure how to proceed from here. Do I try to chemically lower the dKH in the big tank or try to slowly bring up the dKH in the biocube. I've got a bunch of rock flower anemones, zoas, euphylias and a big toadstool that I would really like to survive the transfer in addition to the fish. Any advice would be appreciated!

 

[dadnjesse]

What's the Salinity? Make sure you use a calibrated Refractometer.

 

[Katepete722]

So I believe I’ve discovered the issue. Based on some internet advice I used cyanoacrylate glue and baking soda to cement the rock work together. It seems that despite assurances that this would not affect the water chemistry it definitely has. I checked dKH on the water still in the mixing barrel and it was 10.4. So the issue is definitely occurring in the tank. And the salinity in tank is currently 1.021.