Some of my observations after adding a kalk stirrer [Archive]

reefkoi

06/02/2008, 10:38 AM

I've got a few questions.
I have a deltec km500s kalk stirrer on my 600 gallon reef now, I was tired of seeing the ph barely climb above 8.0 so I thought I'd try the Kalk method. I do run a calcium reactor as well.
My alk has been dropping slowly to about 6.0 dkh over the last few months from the previous level of 7-8.

I now see my ph hovering between 8.0-8.4 depending on time of day. Is this acceptable to have it fluxuate this much?
If not how can I stabilize it?

My alk has gone from 6.0dkh-8.0 since adding the kalk stirrer, I was told kalk wont raise alk just help steady it? Is that true?

I go through about 1-2 cups of kalk per week, it just gets used up that fast, is that ok? should I buy a conductivity meter and install it on the kalk stirrer near the top to see what it reads over the course of a week?

Thanks
Chris

MCsaxmaster

06/02/2008, 11:00 AM

<a href=showthread.php?s=&postid=12661839#post12661839 target=_blank>Originally posted</a> by reefkoi
I've got a few questions.
I have a deltec km500s kalk stirrer on my 600 gallon reef now, I was tired of seeing the ph barely climb above 8.0 so I thought I'd try the Kalk method. I do run a calcium reactor as well.
My alk has been dropping slowly to about 6.0 dkh over the last few months from the previous level of 7-8.

I now see my ph hovering between 8.0-8.4 depending on time of day. Is this acceptable to have it fluxuate this much?
If not how can I stabilize it?

That is perfectly fine, and better than what is often achieved. I wouldn’t worry about that. If you want to try to adjust it, you can dose kalkwasser more at night (or strictly at night) and use the calcium reactor more during the day (or just during the day) making fine adjustments to try to even things out. pH will tend to want to fall during the night—the kalk will help offset that. pH will tend to want to rise during the day—the calcium reactor will help offset that.

<a href=showthread.php?s=&postid=12661839#post12661839 target=_blank>Originally posted</a> by reefkoi
My alk has gone from 6.0dkh-8.0 since adding the kalk stirrer, I was told kalk wont raise alk just help steady it? Is that true?

Not precisely, no. If you add a base to water without an equivalent addition of acid, you’ll raise the alkalinity. Surely enough, Ca(OH)2 adds a base (hydroxide) and no acid (Ca++ is a weaker acid than water, hence it is “neutral”). Thus, if you add kalk to sea water, surely enough you are raising the alkalinity.

However, when we add kalk to a reef tank presumably we have calcification going on. Calcification sucks out calcium and alkalinity (and magnesium and strontium and a few other metals to small degrees). Say we add X gallons of kalkwasser to the tank a day. In those X gallons there will be Y equivalents of alkalinity. If the rate of calcification in the tank consumes less than Y equivalents per day, the alkalinity of the tank water is going to rise over time. If the tank consumes Y equivalents per day, we’ll maintain the same alkalinity. If the tank consumes more than Y equivalents, the alkalinity will drop over time. So whether you can raise, maintain, or not maintain alkalinity (and calcium) with kalkwasser depends on how much you are dosing (practical upper limits there) and how much calcium and alkalinity the tank is consuming for calcification.

<a href=showthread.php?s=&postid=12661839#post12661839 target=_blank>Originally posted</a> by reefkoi
I go through about 1-2 cups of kalk per week, it just gets used up that fast, is that ok?

Yep.

<a href=showthread.php?s=&postid=12661839#post12661839 target=_blank>Originally posted</a> by reefkoi
should I buy a conductivity meter and install it on the kalk stirrer near the top to see what it reads over the course of a week?

Thanks
Chris

It wouldn’t be a bad idea if you want to see whether or not your reactor is giving you saturated kalk. Counterintuitive as it is, often times people get undersaturated kalkwasser out of kalk reactors.

Chris