Why is my alkalinity dropping?

[Crabby48]

Get the lights on and fish. Wouldn’t worry if all is only a little lower in the tank with the ph low. For your tank to mature it needs light. If it’s 7.9 check it in a couple weeks I bet it will be about the same. Also I never saw tropic Marin mix to 8.0. It’s always low 7. Not saying your wrong just what I see over the years with my test kits

 

[Reefering1]

I disagree. I’m not going to add corals if my numbers aren’t stable.

Here's another way to say the same thing as everyone else...
Right now you have brand new tank with practically new water, rocks, biofilter. Nothing consuming elements, maybe the rock is absorbing something, idk. You want to stabilize 1st but there's nothing to stabilize. You need to turn on lights, slowly add fish. Change water and perform maintenance. In a few months the tank will have settled into its parameters based on water changes. Then you start adding corals, they consume elements. Test parameters. When water changes aren't keeping up with consumption, then you start dosing to maintain stability.

 

[Pickle_soup]

@Pickle_soup , laughing with or laughing at?

Yes

 

[Randy Holmes-Farley]

The alk drop you mention is very small and is easily corrected.

Alk can be dropping due to accumulating nitrate, and from abiotic precipitation of calcium carbonate, which is very common in new tanks.

Higher pH will only make that precipitation worse and I’d not use a scrubber until something in the tank will benefit from higher pH.

 

[Reefering1]

The Dr. Has spoken!!

 

[Birdman Broham]

I agree with everyone who answered. Shouldn’t ask questions than feel insulted when ppl reply with honesty. Welcome to R2R

 

[WestCoastReefNoob]

Really appreciate all the feedback I'm seeing on this thread! Reading the initial post, I could have sworn I wrote that. Same salt, same rock/sand, same pretty much everything (except not dosing).
I also added a scrubber to my skimmer, which increased the pH marginally, but since it is stable at 7.9, I'm going to remove that and save for later.
Lights are going on, time for some uglies!