Alk ajustment not working

[VICTORIA]

I went on the Reef Chemistry Calulator to get an ajustment formula.
my current ca was 370 my desired ca was 429. The product I added was Turbo ca by Kent . I added it by a drip method in about 1/2 gal of R.O. water. all was fine I tested the next moring and ca was 429. Thats great.

Now on the alk side of things , my current was 2.8 I wanted to raise it to 3.4 this would give me a balance. The product I used was washing soda it calculated it to be 2.9 tsps. So I mixed it up and added it slowly over the course of the day. The ph never moved off of 8.3. The next moring I tested and the alk was down to 2.63. My question is why did it lower it instead of raise it? Did I do something wrong? What should I do now? Add more? Thanks ahead of time.
Victoria

 

[randy holmes-farley]

Well, it's hard for me to say for sure what's going on, but I'd bring the calcium up to your target with the turbo calcium, and then mostly use the Kent A&B to raise the alkalinity that last bit.

The washing soda should be fine too, and if you want to use it, just keep adding it, but keep a close eye on the pH. It is possible that the Salifert kit is reading low, and the pH is actually higher than you think. In that case, too much washing soda too fast can make the pH rise a lot, increasing abiotic precipitation of CaCO3.

Also, raising the alkalinty may increase the rate at which corals use it.