Am I precipitating (with chart and data)?

[gobble]

I've had trouble keeping my Alkalinity up to 8 dKH since switching to 2 part in December. I may have fallen into the trap of raising to the point where I'm precipitating. What do you guys think?

My tank is a Reefer 450 with approximately 90 gallons of water volume (after accounting for rocks). The tank has a decent amount of SPS corals which are growing well. I kept figuring that the corals were simply growing and consuming the Alk, but with this last measurement going down to 6.9 dKH after raising the dose to 150 ml/day concerns me. My magnesium stays steady at 1400.

The chart shows my measurements and the dose I switched to on the timeline. The line is where I switched to Randy's new high-ph Alk formula.

 

[Randy Holmes-Farley Verified Community Expert]

There's no simple way to know how much abiotic precipitation and how much biological calcification any given tank has.

Both may be expected to increase as pH increases.

 

[gobble]

Any thoughts on how to raise my alkalinity?

 

[Randy Holmes-Farley Verified Community Expert]

Any thoughts on how to raise my alkalinity?

How high is the pH?

 

[gobble]

The daily cycle swings between 8.1 and 8.35.

 

[Randy Holmes-Farley Verified Community Expert]

The daily cycle swings between 8.1 and 8.35.

You'd certainly get less precipitation if the pH was lower, but I can't know how much slower the corals would also grow. I maintained my tank at pH 8.35 to 8.55 for years, but again, I had no idea how much was abiotic and how much was calcification.

In general, if precipitation on pumps and heaters does not seem out of line high, then I'd stay the course.

 

[gobble]

Ok, thanks. It's crazy that I'm now at triple my original dose (that was maintaining alk around 7.5) and I'm still unable to break above 8.0.

 

[Randy Holmes-Farley Verified Community Expert]

Ok, thanks. It's crazy that I'm now at triple my original dose (that was maintaining alk around 7.5) and I'm still unable to break above 8.0.

FWIW, the alk you are currently at is certainly fine. It basically matches the ocean.

 

[gobble]

I might reset and dial back the dose to see if I can maintain my current levels with a lower dose. Thanks again for you answers.