Alkalinity Consumption

[DavidRZ]

I'm new to reefing, this is my first tank. It is a 24 gallon AIO Aquatop that I've been cycling and running for about 3 months now. I added a Favia about 5 weeks ago as well as one cleaner shrimp and a clown.

A week ago I added a torch (2 heads) as well as two small Acan frags. I've been trying to dial in my Alk. Yesterday I had it at 9.3, which is in the range I was shooting for. Today, it was 8.0 (24 hours later). Is it even possible that these few corals are affecting my Alk like this? I'm confused.

 

[muzikalmatt]

I doubt that small of a coral load, especially in such a new tank, is consuming over 1 dKH in 24 hours. However, other things in your tank can consume alkalinity as well such as coralline algae. Do you have much coralline growing in your tank?

Honestly, I would more likely suspect an error in your testing. What sort of test kit did you use? Did you try double-checking your numbers, maybe even with a different test kit or reagent? Also, make sure your test kit and/or reagents aren't expired.

I would recommend testing your alkalinity for a few days in a row at roughly the same time each day. Maybe even test twice each day to make sure your numbers are as accurate as possible. That should give you a more accurate assessment of your tank's consumption rate.

 

[Ocean’s Piece]

Did you take these measurements are the same time? Salinity? Temperature?
All these factors account for what your consumption rate is. Alkalinity fluctuates dramatically throughout the day (on my tank, it’s about a 2 dKH fluctuation). I assume time is the issue here but make sure your temperature, salinity, and all other factors are consistent before taking a measurement.

 

[X-37B]

Any time you get a reading that does not seem right test again.
I test alk daily and a few days ago I got a reading of 6 and I run alk at 8.
I retested and it was 8.
Also I have 3 ways to test alk and always recommend at least 1 other way to cross check.