School me on Kalk dosing

[droyal1110]

I have been reading up on kalkwasser, what it is, what its used for, and what not on reefkeeping articles. I've looked at different setups but I'm still a bit confused.

 

I would really like to just hear the general consesus, whether people suggest it or not, I don't think I have enough SPS to need a Ca reactor, plus I don't really want to spend that much. I'm thinking my preferred method of dosing will be a GSA Kalk reactor.

 

How do I know how much to put in, pros and cons of a reactor, things to watch out for or do differently, all in all is it worth it? I just can't keep up with water changes, more so in the winter and I'm adding more and more SPS, I think its time to supplement.

 

Thanks!

[Brian Ward]

You'll still need to do weekly or bi-weekly water changes. Dosing kalk isn't a substitute for that as it doesn't remove nitrate from the water, nor does it replace trace minerals.

 

Kalk provides additional alk and ca to your tank. You will generally put in about 2 wks worth and let the stirrer run. There are instructions on calculating your actual usage and what the measurement of 2 weeks is. The GSA stirrers are very safe, but you still have the chance of a kalk overdose. This risk goes down by decreasing the amount of kalk in the stirrer (which means you have to replenish more often).

 

You will run all your topoff water through the stirrer. If this is building up too much alk in your tank, then you'll have to somehow run some of your topoff through the stirrer while adding straight RO/DI for the rest, or possibly reducing the amount of kalk in the stirrer at any given time.

 

I like using kalk, and it is a must if you are heading to a ca reactor. The ca reactor will become necessary as you add more SPS when the kalk stirrer won't keep up. With a Ca reactor, the pH of the effluent is very low and you need the kalk to counter that and pull it back up.

 

The other way to go is 2-part. Many people like this because you don't get the pH swings you get with kalk. However, my understanding is that there are other benefits with kalk and I believe it is generally cheaper to automate.

 

Either way, you still need to dose Mg. Mg in the water helps keep the Ca levels up.

[Origami]

Dosing kalkwasser is a great start. There are many benefits including elevated pH, precipitation of phosphates, etc. Of course, you're dosing it because it's an easy and efficient way of delivering a balanced additive providing both calcium and alkalinity in the proper ratio. It is an excellent, low-cost way to start dosing a tank of your size (90 g). Most people using a kalk reactor dose kalkwasser through their automatic top off system, putting all of their top-off through the reactor.

 

In dosing, it's best to add the stuff slowly - to drip it in. That's because saturated kalkwasser has a pH of around 12.5-12.6 under normal conditions. Dripping it in slowly avoids a sudden, undesirable pH spike in your system. Some people that don't have macroalgae refugiums (or who don't run their refugiums on a reverse light cycle) will drip their kalk at night when the tank pH begins to drop. By doing so, they're able to stabilize their diurnal pH fluctuation.

 

The one thing you need to protect yourself against is setting yourself up for a kalkwasser overdose in these situations. One simple way we do this is not to put in our reactors anymore than what your tank will use in say 1 week's time. Avoid the temptation to put a quart of kalk powder in the reactor just so you don't have to service it for a month or more because someday, when part of the top off system fails (like a float switch or level sensor failure), you won't be dumping that month's supply of kalk into your system in a matter of hours.

 

That's really the basics of using it.

 

The discussion on the appropriateness of or outgrowing your means of supplementation is mostly a question of replenishing the material that's being consumed in your tank. If consumption is very low, regular water changes can address the low demand. If higher, you'll find it easier to adopt some other form of supplementation scheme (two-part, kalkwasser, calcium reactors, etc.). If your supplementation scheme over-supplements - that is, if it adds back more than your organisms are taking out - then your calcium and alkalinity levels will begin to rise. If it's inadequate, they will begin to fall. So it's all about maintaining a balancing act.

 

The kalkwasser reactor, by design, attempts to keep the kalkwasser effluent at saturation (a chemistry term). This means that the effluent is carrying as much of the calcium and hydroxide ions as it can given the current conditions (temperature being the main one). Saturated kalkwasser contains around 808 ppm of calcium and 40.8 meq/liter (20,400 ppm). Because this concentration (at saturation) is relatively fixed, dosing kalkwasser through your ATO fundamentally delivers a controlled amount of calcium and alkalinity to your tank depending upon the amount of evaporation your tank experiences. If all of your top-off is run through your kalk reactor and if your evaporation is fixed, you'll be dosing a fixed amount of kalkwasser every day. This may be more than you need, just what you need, or less than you need depending upon you situation.

 

When I was running my 90, my evaporation was somewhere around 1 gallon (3.8 liters) per day. All of my top off went through a reactor, meaning I was adding (3.8 * 40.8) 155 milliequivalents of alkalinity to my tank (around 0.45 meq/l when considering water volume). That's enough to replace about 1.3 dKH of alkalinity consumption by corals per day which was fine for my situation at the start. (Note that 1 meq/l = 2.8 dKH, so 0.45 meq/l = 1.3 dKH.) If consumption is below that, alkalinity and calcium levels will rise in your tank; if below that, they will fall and you will have to either increase evaporation or supplement in some other fashion. Consumption increases as your corals grow, or as you add more carbonate-skeleton producing animals to the mix.

 

One other way of increasing kalk saturation that people use is to add vinegar to their top off water. This slightly acidifies the top off and results in more kalk being dissolved in the kalkwasser.

 

As your tank grows, and with it consumption, you may find that kalkwasser can't do it all. At that point, you'll need to look at possibly adding another supplementation scheme to the picture.

[DDiver]

Can always count on Tom for a long thourough reply....lol

[Coral Hind]

Can always count on Tom for a long thourough reply....lol

 

Agreed, Tom is always full of knowledge! Do we get college credit for reading these posts?

[Origami]

Can always count on Tom for a long thourough reply....lol

 

 

Agreed, Tom is always full of knowledge! Do we get college credit for reading these posts?

 

LOL.

 

(short enough?)

[reefmontalvo]

Brightwell's Kalk +2

[TonyInVa]

I use a DIY auto top off. A pump attached to a float switch, pumps a kalk solution into my sump. This way kalk is added slowly several times a day, as water evaporates.

[Origami]

I use a DIY auto top off. A pump attached to a float switch, pumps a kalk solution into my sump. This way kalk is added slowly several times a day, as water evaporates.

 

If using float switches, I advise using two - one set a little higher than the other and wired serially - so you have a redundant back up in case the first one fails. (I just had one fail on me last week - my first - and this redundant back up kept the little Biocube 29 in my wife's home office from overflowing with fresh top off water.

[Coral Hind]

A disadvantage to using a float switch is that it can add the kalk during the daytime when pH is already high. I would put the float switch on a timer so it only comes on at night.

[droyal1110]

The kalk reactor is by no means to replace doing water changes. However since I can't do one several times a month now I can't rely on the waterchange to replace the used up elements, mainly Ca, plus I've had a surplus of SPS in my tank recently and I want them to do well. I originally swore off dosing but I think kalk is a bit more feasible and less expensive in comparison to Ca reactors.

 

Yea I was thinking of running the kalk only at night but I'm not quite sure how I would accomplish this.

 

I use a jbj ato so it has the auto shut off (set to 7 minutes) through a toms aqualifter. In 7 minutes there isn't enough water (even if it stuck open) to make a dent in my systems day, however with kalk I guess it could be a little more detrimental.

 

The other problem I have with this (because I had no idea how exactly it works) is that my ato isn't always consistent. If I had to guess I'd say I go through about 8 gallons a week of top off, however when it kicks on and off it is random really, its not rhythmic at all.

 

With that said I don't want to set my ATO to be on only at night either, granted there wouldn't be huge swings I just like my water level to be constant. Has anyone done something to get around this? What are most peoples setups... ato and kalk reactor set to as needed or timers or what?

 

Oh and I run a fuge, lights on at night, PH doesn't drop a whole lot at night, I'll do further testing to verify how much it does.

 

Thanks for the help guys.

Edited November 14, 2009 by droyal1110

[Origami]

When running my 90, I just ran it as part of my ato; no night drip since my pH didn't shift much (using a reverse lit fuge).

 

Right now, I just run my ato off of a timer using a peristaltic pump. By adjusting the on-off ratio, I'm able to control precisely how much is dosed.

 

I think you would be fine with running it through your regular, untimed ato.

[Boret]

My JBJ turns off the pump after 3 minutes of continuous operation, not 7.

 

I completely agree with the information these very knowledgeable reefers have shared.

I use a kalkwasser stirrer myself, the smaller one that GSA made (i think Dan just has one size now), and I refill about a cup of kalk every 7-9 days. It has worked great so far.

 

I also use a Ca Reactor that its on 24/7, because I have a lot of Ca hungry livestock.

 

I reached a point where I had to start dosing Mg as well to rise my Ca level @ 480. Right now I am fighting high Alk though and will probably start reducing the time the Ca Reactor is on.