My pH keeps dropping

[CWH]

Howdy reefers!

My pH keeps dropping and I don't know what the heck is happening. My tank:
RedSea Reefer 425G2 - 3 months old -

Had marine velvet from a powder tang I bought at a local shop (learned my lesson about quarantining as it killer every single fish but my chromis). All the coral is doing well thankfully and planning to wait the full 74 days until getting other fish again.

About a week ago, my pH started dropping - I changed the medium in my scrubber. Didn't help. I add pH increaser - pH goes up for a little bit but then drops again in a matter of hours. KH is 10.

I've been adding a ton of Calcium over the last week to inc it from 300 to 420 over the last 7 days or so. Mag dropped to 1220 from 1250 over that time so titrating that back up as well.

Any thoughts? Only thing I can think of is my refugeum is taking longer to grow the chaeto than I projected, so there was a pretty large amount of GH growing in there and I pulled a few large clumps out so perhaps that is making the O2 drop? Chaeto is on backorder in most of the reputable places so I was going to buy 16oz of sea lettuce to boost the O2.

 

[Randy Holmes-Farley]

If you want useful pH advice, it is necessary to know what the pH is, how much it dropped, and how you measured it.

pH increaser is just an alkalinity supplement. Stop using it unless you want to raise alkalinity.

I also do not believe that magnesium dropped 30 ppm in 7 days. Normal consumption is 1/10th of the calcium consumption, or less.

I'm also suspicious about calcium at 300 ppm. Either the salinity is low, the test is off, or you drive it down by adding too much of the pH increaser. Probably a mix of all of those.

This will help you understand pH issues:

pH and the Reef Aquarium - REEFEDITION

by Randy Holmes-Farley For many aquarists, pH is not something that they have much experience with aside from their aquarium. For many, pH is almost a black box measurement: something to be considered, but whose physical meaning makes little sense to them. This article will Read more here...

www.reefedition.com

 

[mnl119]

Any thoughts? Only thing I can think of is my refugeum is taking longer to grow the chaeto than I projected, so there was a pretty large amount of GH growing in there and I pulled a few large clumps out so perhaps that is making the O2 drop? Chaeto is on backorder in most of the reputable places so I was going to buy 16oz of sea lettuce to boost the O2.

It's not likely due to O2 drop but rather CO2 buildup, if that's the issue. Is it a crowded tank? Also keep in mind, the ambient air inside our houses in winter is more CO2 laden that in summer months.

Is it possible to add a powerhead where the output breaks the surface, thus aiding gas exchange?