Events-->Check alk and calc daily

[daddy2kids]

What events can drastically alter consumption of alk and calc in an LPS reef tank?

I've been dosing Randy's Recipe #1 (from BRS) for about a year. I think I'm into a pretty good routine, e.g., ~ 15 ml alk both morning and evening and ~22 ml calc in the evening. I check alk and calc once or twice per week and am usually pretty close to my targets of ~3.5 mEq/L alk and ~435 ppm calc for all my LPS. I simply adjust a dose or two and I’m good to go for the week (e.g., by decreasing one 15 ml alk dose to half that drops me about one-eighth of a mEq/L if I’m a little over).

Every once in a while, though, my alk and/or calc are WAY off even after not missing a dose or doubling a dose. By “way off” I mean I am off by maybe 50 ppm calc and/or maybe 1.5-2 DKH off, which is a lot more than I would think. It’s like someone threw a switch and BOOM the tank is using much less/more alk/calc and I am way off by the time I do the test the following weekend.

Is there a list of events that would cause me to check my alk and/or calc more frequently than weekly? Do you have such a list handy or will you please help me brainstorm such a list?

For example, I now know that when I do any of the following, I start checking my alk and calc daily for a day or two to be sure I am not over-dosing or under-dosing:
1. Add any new corals;
2. Remove any corals; and/or
3. Prune my cheato (I learned this one the hard way).

Thoughts? Thanks in advance, everyone.

[bertoni]

Interesting that pruning the Chaetomorpha changes the alkalinity consumption. Does it go up or down?

I'd only add a few obvious items to the list, like live rock changes of any kind (coralline), or maybe even a large change in the feeding rate. I can't think of a good comprehensive list I've seen.

[daddy2kids]

I will have to check my notes, but I think alk consumption drops when I prune my Chaetomorpha.

I didn't think of coralline. Now that you mention it, I think the last time I soaked all my powerheads in vinegar, both alk and calc consumption dropped, but I did not associate that with the cleaning. Good catch.

I will try to pay more attention to my feeding. I am always trying new feeding regiments because I am adding new corals, e.g., feeding oyster eggs to my new goniopora and more cyclopeze and mysis for my new black tube coral.

[bertoni]

Okay, I can believe that it's possible that the Chaetomorpha might reduce coral growth by consuming nutrients. That's very interesting. No one's ever posted that before. Thanks!

[Randy Holmes-Farley]

Or maybe pruning it releases something that slows coral growth. :)

[Masterofnonsense]

I noticed my alk consumption jumped way up when I added some Rox carbon to polish my water. My 2 hypotheses are that the carbon absorbed some of the alkalinity. Or, I had a compound in my water that my corals didn't like, and the addition of carbon absorbed that, and my corals are growing faster.

I do have quite a bit of bubble algae and cyano growth in the tank, but my sps corals weren't brown, so I haven't been very aggressive at reducing nutrients. Also when I change out my filter socks, there is reasonably strong odor that smells kind of like iron or rust ish.

I could believe that the algae might bother corals, and that pruning the algae back could lead to better coral growth throwing off your dosing numbers.

[bertoni]

Or maybe pruning it releases something that slows coral growth. :)
That's another possibility. :)

[Randy Holmes-Farley]

I noticed my alk consumption jumped way up when I added some Rox carbon to polish my water. My 2 hypotheses are that the carbon absorbed some of the alkalinity. Or, I had a compound in my water that my corals didn't like, and the addition of carbon absorbed that, and my corals are growing faster.

I do have quite a bit of bubble algae and cyano growth in the tank, but my sps corals weren't brown, so I haven't been very aggressive at reducing nutrients. Also when I change out my filter socks, there is reasonably strong odor that smells kind of like iron or rust ish.

I could believe that the algae might bother corals, and that pruning the algae back could lead to better coral growth throwing off your dosing numbers.

I do not believe that GAC binds appreciable alkalinity. :)