low alk/hi PH, calc 420 one time correction?

[spidey07]

So I've studied the alk/calc articles much (thanks randy, wonderful work)

I've had trouble maintaining alk/calc in a 30 gallon cube dominated by LPS with a few SPS as the corals are now much larger and growing out the wazoo. I dose about 25-30 mL b-ionic daily.

alk is still dropping and is now 6.8 dKh
Calc is maintaining steady if not rising slightly at 415
Mg is 1350

pH has gone from 8.2 to 8.4 over time (1 month)

Am I to understand that I can just dose straight baking soda for a one time correction to raise alk with no other impact other than a slight reduction in pH? Then continue b-ionic to maintain? Using the calculator I get 1.65 teaspoons for a water volume of 25 gallons to arrive at 10.5 dKh.

The reason i ask is I can see my LPS corals are not to the full extension they normally are (don't know if that is pH or alk related)

thanks in advance, hopefully thanks to your articles I've answered my own question.

 

[Randy Holmes-Farley]

I would keep the alkalinity at or above 7 dKH.

You could do a boost with baking soda, but I expect that you'll need to boost more every day to keep up. The higher the alkalinity the higher the demand for it, so it takes more to keep it higher.

Try adding more of the B-ionic every day. A pH of 8.4 is not too high, even up to 8.5 is OK. Maybe try 40 mL per day.

If cost is a concern, you can try to make your own:

A Homemade Two-Part Calcium and Alkalinity Additive System
http://www.advancedaquarist.com/issues/april2004/chem.htm

Improved DIY Two Part Recipe
http://www.reefcentral.com/forums/showthread.php?s=&threadid=742944

 

[spidey07]

Thanks a bunch.

I guess my demand is just getting very high. There's a lot packed into that little cube.

 

[Randy Holmes-Farley]

You're welcome.

Good luck.