Synthetic Rock Leaching Alkalinity & Soaking up Calcium?

[samba_dad]

I have a fish-only tank currently and I purchased a Neptune Trident. I thought it was malfunctioning until I confirmed the measurements with a 3rd party test kit. I use Aquaforest Reef Mix salt with RO/DI water. I also used the Aquaforest synthetic rock. The Aquaforest salt is supposed to mix to 7.7-8.3 Alk, 440-460 Cal, 1360-1420 Mag. The Neptune was providing an Alk out of range error. When I tested with my Hannah kit it read 15.7 dKH. The Calcium is around 100 ppm (maybe lower). Has anyone experienced anything like this with synthetic reef rock?

 

[ReefStable]

Honestly, I think the salt was likely not mixed consistently in the box.

What's the rock made from? It's possible, but unlikely unless it is from a stone like lime that is dissolving.

 

[Pistondog]

You can check the aquaforest batch for icp results, code number on bag.. I use their reef salt and have not had the problems you describe.

 

[Randy Holmes-Farley Verified Community Expert]

Cement rocks that are not fully cured can release alkalinity. I don’t know but think it unlikely it would drop calcium noticeably.