BRS160 Video on Calcium, Alkalinity and Magnesium

jgvergo · Feb 5, 2016

I'm getting close to starting up my first reef, but I'm still studying. I just watched this week's video. As usual, it was very instructive. I have also read a fair amount in this forum as well. I already bought a BRS 2 Part kit and I understand how to measure and adjust Calcium (420), Alk(8.5 dKH) and Magnesium (1300 ppm) to their target levels.

HOWEVER, what is not clear to me is how to maintain a ph of 8.3. If a nail my Ca, Alk and Mg levels, will ph usually stabilize at 8.3? If not, how do I adjust it while maintaining the levels of Ca, Alk and Mg?

JimWelsh · Feb 5, 2016

Don't chase pH. Monitor and maintain stable alkalinity. If after doing so, your daily pH values are not within a range of 8.0 to 8.3 or so, then it will most likely be lower, and the most likely cause for this is excessive CO2 inside your house. The best remedy for this is to open a window, or else provide outside air to the intake to your skimmer.

Randy Holmes-Farley · Feb 5, 2016

pH is determined mathematically by the alkalinity and the CO2 level in the water.

With respect to additives, if the pH is low, all you can do is that when you need alkalinity, use high pH additives.

As Jim mentioned, the other way to approach it is to reduce the CO2 level in your home air or a skimmer inlet, or reduce it in the water (growing macroalgae, for example, or using limewater (kalkwasser) for calcium and alkalinity, or a CO2 scrubber on a skimmer air intake).