HancatAquariums

That’s what I’m thinking as well, it just seems off. Of course it’s still my fault for not being more on top of checking my GH, however, I wish I could pinpoint the issue more clearly so I can ensure not to make it again. I appreciate your help tremendously!

The salinity has remained at 1.011 for the last two weeks, I keep a lid on it to help with evaporation, so thankfully with it being such a high volume of water the salinity doesn’t fluctuate as much. However, my GH for this tank is usually 8-12. The only thing I’ve changed that I can think of was I added a new bag of crushed coral (20lb) roughly ~3 weeks ago. However, if my water is pretty alkaline, I’m struggling to understand how it would continue to buffer so heavily that my GH reached such an extreme ppm. (I’ve also done this in the past with no spike in GH)

I use Red Sea marine salt, and seachem prime. I fill my bucket with tap, dose prime, then use a refractometer to dose the marine salt to 1.010-1.012 salinity. Other than that, I don’t have anything additional in my filters besides basic matrix and filter floss. **I’m attaching a pic of the tank for better visualization. ** Live rock, driftwood, crushed coral substrate, fake plants (little to nothing plant wise survives in this salinity).

I have a 55 gallon brackish tank I keep a GSP puffer in. The tank was set up almost three years ago originally for a figure eight puffer which unfortunately passed a few weeks ago. The tank sits at 1.010-1.012 salinity, temp 76-78, live rock, crushed coral substrate, an internal canister, a sponge filter, and an external aquaclear filter. Biweekly water changes 30-40%. Parameters: 8 ph, 0 ammonia, 0 nitrites, 0-5ppm nitrates. 900+ GH (according to my local shops automatic API tester). My question is: why has my GH in this tank suddenly skyrocketed to extremely unsafe levels? I do not add any chemicals to this tank whatsoever, besides prime and marine salt. I’m completely flabbergasted as to what would cause this sudden increase (the crushed coral isn’t exactly new?) Any advice is helpful, I just want to figure this out for my puffers sake, thanks! **I also want to mention the reason I use crushed coral and live rock is my tap sits around 6.2 ph, most of the puffers I keep prefer 7.8-8.2.