CaRx: Low Alk but high Ca and Mag

[RaymondsWorlddd]

Im thinking I may not understand things as much as I do and now I need help.

I have a 50g SPS dominant (mainly frags). I have a CaRx running 8a-8p with a pH of 6.5 running at 25mL/min. I have a kalk stirrer running 8p-8a at 2mL/min to help with pH swings. I recently decided to start a CO2 scrubber to help with pH swings as I’m still getting 7.7-8.1.
Current levels:
Alk 7.1
Ca 500
Mag 1530
NO3 6.7
Phos 0.1
I use Red Sea blue bucket.

What should I do to raise my Alk but lower my ca and mag?

 

[Zero_Cool]

Slow the CaRx dosing rate.

Raise the pH in the reactor so less of the media dissolves.

Reduce the time the CaRx is dosing.

 

[RaymondsWorlddd]

Slow the CaRx dosing rate.

Raise the pH in the reactor so less of the media dissolves.

Reduce the time the CaRx is dosing.

My goal is to get the all into the 8.2-8.4 range. Do you think decreasing the ph settings would not help raise my Alk?

I’ll raise my pH to 6.6. I use Reborn media btw.

 

[Randy Holmes-Farley Verified Community Expert]

I don't think you need to reduce calcium, but if you want to, and salinity is not too high (so you wouldn't reduce calcium and mag by reducing salinity), then reduce the input from the reactor and dose an alk supplement for a while.

 

[jda]

I would run the CaRx 24/7 and tune it based on output/mix and not chamber pH. There is a Google Doc in my signature that explains how to do this. This will help with your tank pH, too.

I have used CaRx for decades. They mostly supply in balance, but a few times a year, I have to manually add some alk or calcium to get levels back again. This should not need to be done too often. This happened a lot more when I had huge clams that do not appear to use carbonate and calcium in balance.