baking soda addition


Hey Randy,

I have been tracking my cal and alk usuage each week now for several monthes trying to find the sweet spot for how much daily additive of baking soda and dow flake to maintain 440 ppm calcium and 4 meq of alkalinity and can't seem to hit it. I'm using IO reefcrystal for salt and do 20 gallon wc on a 160 gallon system every 2 weeks. I don't seem to have any problem hitting the calcium usage but the alk is tough. When using the calculator I'm up to 55 gms/week baking soda addition. I have probably 55 frags and 2-3 colonies of sps in my tank with a goodly amount of coraline algea. I use lime water for all make up that I mix in a 32 gallon container with 2 cups of pickling lime and 2 cups of vinegar. I don't notice any precipatation on my pumps (well no more than what I consider normal).
Does this seem to be a lot of alk usage? Should I be looking for a problem someplace? Do you think my targets of 440 and 4 are resonable? Thanks in advance.


My target is 4 meq but I don't seem to ever get there. The best I seem to be able to do is 3.5-3.6 with this type of addition. I have recently added a couple of frag packs (about 30 sps and lps) so I imagine my usage will change as they settle in and begin growing. I attempt to add baking soda and dowflake each day instead of bigger doses once a week (if I don't forget:)). Should I be worried about that much baking soda?

Randy Holmes-Farley

Reef Chemist
Premium Member
FWIW, 3.5 meq/L is perfectly fine, and I wouldn't pull my hair out over that difference. However, 55 grams of baking soda per week in a 160 gallon system is not very much. A high demand system might need more than 35 grams per day.