Do i always dose calcium with alk?

._Z_. · Jan 9, 2018

If it makes you feel better I’m seeing a similarity in my tank. It’s going on 4 months old. I’m using BRS kalk in my ATO, but I’m seeing alk drop while my calcium stays pretty stable (testing with salifert). I’ve been using Randy’s alk part of his 2-part recipe to keep the alk up.

I was operating under the assumption that there are organisms using carbonate at a higher rate than calcium in my tank, coralline one of them. But this was just an assumption.

Herby’s reef · Jan 9, 2018

._Z_. said:
If it makes you feel better I’m seeing a similarity in my tank. It’s going on 4 months old. I’m using BRS kalk in my ATO, but I’m seeing alk drop while my calcium stays pretty stable (testing with salifert). I’ve been using Randy’s alk part of his 2-part recipe to keep the alk up.

I was operating under the assumption that there are organisms using carbonate at a higher rate than calcium in my tank, coralline one of them. But this was just an assumption.

I was thinking the same thing!

David

Herby’s reef · Jan 9, 2018

Randy Holmes-Farley said:
At the rate of alk addition, you are consuming about 7 ppm of calcium per day. It may take a while to see that change with a kit, and water changes may also be propping it up.

I'd personally dose the calcium unless the calcium unless it is already too high (500+ ppm), and if anything, yours is on the low side.

Ok, I will start dosing the calcium also and see what happens.

Thanks so much!

bif24701 · Jan 9, 2018

Don’t ever add calcium and ALK together directly. They need to disperse before adding the next. If you are doing 2 Part then yes, if you add ALK then you should also be adding Cal in the same ratio if you mixed according to directions.

Stevesreef225 · Jan 10, 2018

I have the same problem. My cal is 440 mag at 1440 and my alk is 7.8. Constantly adding alk but never calcium. I use API and Red Sea foundation pro test kit.

._Z_. · Jan 10, 2018

Found this article (I think by Randy), which I found helpful on this topic

http://reefkeeping.com/issues/2006-06/rhf/index.php

Randy Holmes-Farley · Jan 10, 2018

This one can also help people understand those unusual situations (aside from water changes with a mix not matching the tank) where calcium and alkalinity demand do not exactly balance:

When Do Calcium and Alkalinity Demand Not Exactly Balance? by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2004-12/rhf/index.htm

Herby’s reef · Jan 10, 2018

Randy Holmes-Farley said:
This one can also help people understand those unusual situations (aside from water changes with a mix not matching the tank) where calcium and alkalinity demand do not exactly balance:

When Do Calcium and Alkalinity Demand Not Exactly Balance? by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2004-12/rhf/index.htm

Thanks Randy! That helps so much! I have started adding both sides of the 2 part and so far my calcium has not budged. Just as your article says!

Thanks. I really appreciate the advice.

Herby’s reef · Jan 10, 2018

._Z_. said:
Found this article (I think by Randy), which I found helpful on this topic

http://reefkeeping.com/issues/2006-06/rhf/index.php

Thanks! I had not read that one. It is very helpful!

Emerson · Jan 11, 2018

Great thread! I have a young (9 months) 75 gal mixed reef set up with a 6-7 small (but growing) sps frags, 4-5 small lps frags, and 4 larger lps (brains, frog spawn, goniopora). I've been testing alkalinity with Hanna tester, Ca and Mg with Salifert kits. I do ~15-20% water changes (RS Pro + RO DI) every 4 weeks. I use BRS 2 Part and Mg trying to keep dKH ~8.0-8.5, Ca ~420-450 ppm, Mg ~1300 ppm.

I've had a very similar experience in trying to keep "stable" chemistry. Alkalinity demand has been low enough that I manually dose ~30ml BRS alk solution every 3-4 days when the alk level drops below 8.0 (raises alk about 0.5 dKH for my system). Ca levels remain very stable dropping maybe 20-30 ppm in a month. Not wanting to put in too much Ca additive I have often only dosed alk 2 part solution thinking I was avoiding a high Ca imbalance. Reading this thread makes me think I've been improperly trying to maintain alkalinity level without supporting Ca levels.

@Randy Holmes-Farley: having just read both articles listed above (thanks again for your Yoda-like chemistry explanations), you describe Ca demand as being hidden by other factors, and as a matter of practice recommend keeping 2 part additions equal?

Randy Holmes-Farley · Jan 11, 2018

Emerson said:
@Randy Holmes-Farley: having just read both articles listed above (thanks again for your Yoda-like chemistry explanations), you describe Ca demand as being hidden by other factors, and as a matter of practice recommend keeping 2 part additions equal?

The main things it is hidden by are water changes with a mix above tank levels, and the fact that it's daily decline is typically to small to accurately see with most test kits.

Few people will have a problem if they use equal; parts dosing, and make small tweaks to that over time IF calcium is getting too high or too low.

Users of two parts seem to blame all kinds of issues on uneven demand and "adjust" the dosing, while users of CaCO3/CO2 reactors and limewater (both with roughly fixed addition ratios) do not seem to have the same propensity. lol

Herby’s reef · Jan 12, 2018

Ok guys, I got the Red Sea tests in and they do indeed show a higher alk than my API test did. The API showed me at 8ish and the Red Sea says 9.5. I’m not sure how important this information is though as I have started adding my 2 part in equal amounts as Randy suggested. The results have been a much more stable alk, and my calcium has not elevated much over where it was. It is now around 42o. Thanks so much for all the advice! I have learned so much from this!