Low Alk, normal Cal?

[matthewscars]

I've been reading the articles and had a question.

My stats are:

PH: 7.77 - 8.1
ALK: 6.4 dKH
CAL: 440
MAG: 1350
Temp: 78-79

Any reason the ALK is so low? Should I be concerned?

I ran the ALK test twice to confirm.

Any ideas?

[bertoni]

Alkalinity gets consumed very quickly in many tanks, and most require daily supplementation. There's a lot more calcium in the water in terms of calcium carbonate equivalents, so that parameter drops more slowly, at the rate of 2.8 dKH to 20 ppm calcium.

[B.C.theReefer]

I was having the same problem recently. As many others advised, daily alk. supplementing might be needed. As it turned out, they were right. I use baking soda as my alk. supplement and have to add about two and a half tea-spoons everyday for 120gal total volume. I dose this in halves. One in the morning and one at night. It took a few days to figure out how much to use. But now that I have the dosage figured out it has become routine. I still test before adding any alk. OR calcium to be sure I'm not over doing it.

Now I know why people that have alot of SPS run calc. reactors. Daily dosing is kind of a bummer. But it's worth it. Maybe someday I can afford to set up a reactor. It'll probably be the day I literally get sick to my stomach from adding stuff to my tank 7 days a week.

Good reefing!

[HighlandReefer]

If you use kalk in your top-off water, it would decrease the need for additional calcium & alk. dosing.

[matthewscars]

I transfered the tank from a 55 into the new 90. It's been up for 2 months tops. I have all softies, 2 LPS and 2 SPS. They are all frags so they arent taking up anything. I'll keep up the water changes of 10% a week and see how it goes.

Im hoping its just a new tank establishing thing. Ill dose as needed though.

[Randy Holmes-Farley]

Why do you think they are not taking up anything? Even coralline algae alone can be a substantial user of calcium and alkalinity, and that is most easily seen with drops in alkalinity if it is not adequately supplemented.

[matthewscars]

I'm /assuming/ that since i have 2 - 1" sps frags and some left over coraline on the rocks i transfered over, that it wouldnt have such an impact on a 110g total water volume. I dont have an ATO. I have my RODI running directly to the tank and I ball-valve it on once every other day to top off 3 gallons or so.

I could be wrong, and if you say I am, I believe you. :)

Should I use baking soda, or a Kent Marine Tech-CB?

[Randy Holmes-Farley]

I'd use the Tech CB unless the calcium gets too high (it is perfect now at 440 ppm)

It won't take much to keep the alkalinity up if the demand is not too high. :)