Kalk reactor efficiency

Bartwick · Oct 21, 2019

Hi Randy,
You provided me with some great information a few years back on the other website about calcium hydroxide. You had said that EC or electrical conductivity is the way to identify how much calcium hydroxide is dissolved in the Kalk solution. EC meters can be cheap but the ones in the needed range are way too expensive. I asked a few vendors if they had ever measured the calcium hydroxide concentration coming out of the their reactors. None had.

I'm wondering if you are aware of any studies done on this. If not, do you have an opinion on the effectiveness of the various stirrers on the market? Based on my experience from when I would to shake or stir Kalk, I tend to think that the stirrers can't be very good. Nilsen reactors mix with a pump and seem much better but people report that the impellers don't last long in the Kalk. For the past 2 years I've used a diy reactor employing a magnetic stirrer set on a timer to mix twice a day and giving 3 hours for the solution to settle before dosing. I haven't needed a chemically resistant stir bar. When I noticed that the acrylic was getting worn down by the stir bar I put a piece of glass on the bottom solving that problem.
Thanks

Randy Holmes-Farley · Oct 21, 2019

Well, I’ve done it and devices in the right range are not expensive. Any conductivity probe meant for seawater can do it.
I’ll link an article of mine in the next post

Randy Holmes-Farley · Oct 21, 2019

The Degradation of Limewater in Air - Reefkeeping.com

Randy Holmes-Farley · Oct 21, 2019

Figure 4 shows the method works

Bartwick · Oct 21, 2019

Thanks! You're right about the range of the meters and my meter goes up to 19.99 mS/cm. Unfortunately, I can't report on my reactor right now because the batteries are dead. For me it's really easy to clean and refill my reactor once a month. If I find that I'm getting consistently high concentrations I'll keep it. Otherwise I'll join you in mixing in my top-off container, a 22 gal brute slim jim.

lbacha · Oct 21, 2019

I use a Avast K1 stirrer. I really like it as it is gravity fed (you dose water into it and it just flows into the tank) I have been using it for 8 months now and the ph in it is always 12.5 (measured with cheap ph strips). The real proof is my alkalinity is extremely stable. I get swings from adding coral and I eventually have to increase as growth occurs but it does t swing much day to day at all so I would consider it a solid product.

what I really like is there are 0 mechanical parts exposed to the kalk. The only whiny I check is the output because it will form a crust overtime and I learned the hard way it will plug up. Now I clean it every other week when I add new kalk and no issues since

Bartwick · Oct 22, 2019

I'm a huge fan of Avast. I have lot's of their stuff. My diy Kalk reactor is very similar to theirs but uses a magnetic stirrer. It goes on for 10 minutes twice a day and the my apex ATO programming waits 3 hours before dosing the Kalk for top-off. It's been without problem except when I noticed that the acrylic bottom was getting worn away by the stir bar. I put 1/8" glass on the bottom with a liquid epoxy. Problem solved.

In Randy's article, under "Measuring the Potency of Limewater" he describes the limitations of pH and suggested conductivity as a better measure. Figure 4, which he points out, shows that conductivity is proportional to dissolved calcium hydroxide as a percentage of complete saturation. Completely saturated Kalk solution has a conductivity of about 10 mS/cm. A conductivity of 6 mS/cm would indicate that the solution is 60% saturated.

Could you perhaps measure the conductivity of your reactor and report back? Thanks.

lbacha · Oct 22, 2019

Bartwick said:
I'm a huge fan of Avast. I have lot's of their stuff. My diy Kalk reactor is very similar to theirs but uses a magnetic stirrer. It goes on for 10 minutes twice a day and the my apex ATO programming waits 3 hours before dosing the Kalk for top-off. It's been without problem except when I noticed that the acrylic bottom was getting worn away by the stir bar. I put 1/8" glass on the bottom with a liquid epoxy. Problem solved.

In Randy's article, under "Measuring the Potency of Limewater" he describes the limitations of pH and suggested conductivity as a better measure. Figure 4, which he points out, shows that conductivity is proportional to dissolved calcium hydroxide as a percentage of complete saturation. Completely saturated Kalk solution has a conductivity of about 10 mS/cm. A conductivity of 6 mS/cm would indicate that the solution is 60% saturated.

Could you perhaps measure the conductivity of your reactor and report back? Thanks.

Unfortunately no easy way to measure conductivity on it, Alk has been extremely stable for 10 months now since I put the kalk stirrer on. I add new kalk every 2 weeks to the reactor and 0 jump in Alk so I’m comfortable that it’s staying consistently saturated (may not be 100% but it is a stable percentage)

MuffinMonster · Jan 20, 2020

Randy Holmes-Farley said:
The Degradation of Limewater in Air - Reefkeeping.com

So i have ran kalk in my ATO, im not a fan of that. I love kalk though and how easy it is, can i essentially just mix kalk with RODI to the point of saturation in a separate container and dose it with a dosing pump instead of using a kalk reactor? Why are people using kalk reactors over mixing it in a bucket and dosing it with a pump? Im not a fan of it in my ato just due to not being able to control it/dial it in as much as evaporation changes.

Randy Holmes-Farley · Jan 21, 2020

MuffinMonster said:
So i have ran kalk in my ATO, im not a fan of that. I love kalk though and how easy it is, can i essentially just mix kalk with RODI to the point of saturation in a separate container and dose it with a dosing pump instead of using a kalk reactor? Why are people using kalk reactors over mixing it in a bucket and dosing it with a pump? Im not a fan of it in my ato just due to not being able to control it/dial it in as much as evaporation changes.

Sure. That method works well.

DidYouSayReefer · Jan 22, 2020

MuffinMonster said:
So i have ran kalk in my ATO, im not a fan of that. I love kalk though and how easy it is, can i essentially just mix kalk with RODI to the point of saturation in a separate container and dose it with a dosing pump instead of using a kalk reactor? Why are people using kalk reactors over mixing it in a bucket and dosing it with a pump? Im not a fan of it in my ato just due to not being able to control it/dial it in as much as evaporation changes.

People like gadgets. Many ways to skin a cat.

ToadallyNC · Feb 22, 2021

Randy Holmes-Farley said:
Well, I’ve done it and devices in the right range are not expensive. Any conductivity probe meant for seawater can do it.
I’ll link an article of mine in the next post

Hi Randy! What pen would you suggest using? I’ve seen one on BRS that is quiet expensive. Is the EC pen and TDS pen the same? Thanks!

arking_mark · Feb 22, 2021

ToadallyNC said:
Hi Randy! What pen would you suggest using? I’ve seen one on BRS that is quiet expensive. Is the EC pen and TDS pen the same? Thanks!

Following for the answer...I have a GHL that can measure, but would require taking out a portion to measure. An inexpensive pen would be great!

Dennis Cartier · Feb 22, 2021

I took Randy's advice and switched to using EC for tracking the strength. Works great. I use a Milwaukee EC meter that is targeted at the horticulture industry. The one I use is a MW-302. It has a range of 0-10ms, which is a tad low for full strenth kalk (10.5ms), but it actually reads over 10ms slightly, which is good enough for my purposes.

Dennis

Randy Holmes-Farley · Feb 23, 2021

I generally prefer a conductivity meter with a cord between the probe and the meter so that you can read continuously in a bucket, the aquarium, etc.

I used and like an old Orion conductivity meter (I had #128). They can sometimes be had on ebay.

Most meters should be adequate for measuring limewater potency if they cover the right range.

Dennis Cartier · Feb 23, 2021

I have bought a few Thermo Orions off Ebay. It can be kind of confusing to know what goes with what, so here is a cheat sheet for those looking to buy one.

conductivity probes with 2 electrodes start with 011
conductivity probes with 4 electrodes start with 013 (4 better than 2)
conductivity probes ending with just numbers are for the meters without an A after their model #
conductivity probes ending with A are for the meters with an A after their model #
conductivity probes ending with MD are for the Star series meters
conductivity probes ending with 50(xx ) are for freshwater and only cover 0 - 20 ms
conductivity probes ending with 00(xx) or 10 are for saltwater and cover 10 - 200 ms

A couple of the digits indicate the cord length and material the probe is made from. I suggest sticking to epoxy for tank use.

Dennis

reefinnewb · Jul 22, 2021

I just bought a Hanna Dist 4 and it works fine.

Randy Holmes-Farley · Jul 22, 2021

reefinnewb said:
I just bought a Hanna Dist 4 and it works fine.

I'm not doubting that, but how do you know it works fine?

reefinnewb · Jul 22, 2021

Randy Holmes-Farley said:
I'm not doubting that, but how do you know it works fine?

Measures from 0.00 - 20.00 mS/Cm. Calibrated perfectly, Reads fully saturated Kalk in one cup of rodi with 2tsp of Kalk added. Just not a probe so it's a more manual process.

Randy Holmes-Farley · Jul 22, 2021

reefinnewb said:
Measures from 0.00 - 20.00 mS/Cm. Calibrated perfectly, Reads fully saturated Kalk in one cup of rodi with 2tsp of Kalk added. Just not a probe so it's a more manual process.

OK, the "calibrated perfectly" was what I was asking about.