$40 DIY Kalkwasser Reactor for RO-fed ATO

I just wanted to share an easy DIY project that provides a cheap alternative to expensive kalk reactors. Depending on where you source the parts and what parts you already have lying around, this should cost ~$40 to build. It is a reliable, and professional-looking system that you can't mess up. This kalk reactor is plumbed into my RO outlet ATO that is always on. You could just as easily plumb it to a solenoid and powering a powerhead from a separate RO ATO reservoir. This system mixes 000 TDS RO water with Kalk and then feeds it into a float valve placed in the sump of my display.

***Before you go bashing me for running limewater through the narrow 1/4" tubing and then to a float valve (which would easily clog the system), know that the limewater - although saturated with a PH of 12 - is mostly clear and does not contain the big chunks of white lime that usually cause clogs. :smash:

Parts list:

• 1x Clear 10" filter housing ($20 on eBay shipped)
• 2x 1/4" threaded/push to fit connectors (<$1 at HomeDepot)
• 2x 1/4" shut off ball valves (~$5 at HomeDepot)
• Various check valves (at your discretion) to keep the water flowing forward (<$1)
• 2x 1/4" push to fit 'T' fittings (<$1 at HomeDepot)
• Kalk/Lime ($8)
• RO Tubing (Negligible)
• 1x 5-6" length of 3/4" PVC (~$1 at HomeDepot)
• 1x 3/4" PVC cap (<$1 at HomeDepot)

Total Cost: ~$40

Tools:

• Power drill
• PVC glue (Blue 'Rain' or 'Wet' type)
• Teflon tape
• RO tube cutter

Instructions:

1. Lay out all of your parts on a flat work space and make sure you have everything you need, including tools.
2. Use teflon tape to go over the threads of your 1/4" threaded/push to fit connectors.
3. Slowly thread the 1/4" threaded/push to fit connectors into both ports on the filter housing until snug.
4. Open filter housing and turn the top over. You will see a small 'nub' or 'nipple' where you will attach the 5-6" PVC stem. Apply glue to one end of the 5-6" PVC pipe and attach it to this nub. Turn the PVC pipe 1/4 turn and let cure for ~10 minutes.
5. While waiting for the glue to cure, use a very small drill bit (the smallest you have to increase pressure of the output water) to drill a hole in the center of the 3/4" PVC cap.
6. Apply glue to the other end of the now-attached PVC stem and attach the 3/4" PVC cap. Turn the cap 1/4 turn and let cure for ~10 minutes.
7. Insert kalk into clear filter housing so that it covers the tip of the stem which is the 3/4" PVC cap.
8. Connect all RO tubing. Make sure you connect the output of the RO to the 'out' port of the filter housing and then connect the float valve side to the 'in' port on the clear filter housing. This is counter-intuitive, I know but, it must be plumbed this way for the filter housing to be used correctly in this application.
9. ***See diagrams and pictures below to see where I attached to valves, tees, and check valves.***

Pictures and Diagrams:

RO Tubing Route Layout:

Incoming water splits into a 'T' with ball valves on either side. After the valves, one side goes into the reactor and one side goes around the reactor. The one that goes around the reactor connects with the output of the reactor by means of another 'T'. From here, the water finally enters the float valve. This is to create a bypass. The purpose of the bypass is to adjust the amount of pure RO mixing with the kalk and the amount of pure RO going directly into the sump. If your evaporation is high and you have all or most of your RO ATO water reacting with the kalk, your PH could rise to unsafe levels and do serious damage to your tank inhabitants. Having these valves allows you to regulate if you want 100% pure RO top-off, 80% pure RO top-off and 20% kalk top-off, etc.
http://www.o-r-c-a.org/forum/attachm...tid=3899&stc=1

Another view:
http://www.o-r-c-a.org/forum/attachm...tid=3900&stc=1

Kalk first added and initial mixing (note the cloudy top layer of water above the condensed bottom layer):
http://www.o-r-c-a.org/forum/attachm...tid=3902&stc=1

After kalk has mixed, saturated the solution, and settled (note how the top layer has gone from cloudy in the previous picture to clear now that it has settled):
http://www.o-r-c-a.org/forum/attachm...tid=3903&stc=1

Output to sump via float valve:
http://www.o-r-c-a.org/forum/attachm...tid=3901&stc=1

So that's it! It has been up and running for a few days now with no issues. My Ph is up (in good levels), my Alk is up, and my Calcium is where it should be. This reactor has no moving parts and is cheap and easy to build. Let me know what you think or if you have any questions.

General idea of how it looks:
http://www.o-r-c-a.org/forum/attachm...tid=3904&stc=1
Tubing route diagram (don't laugh):
http://www.o-r-c-a.org/forum/attachm...tid=3905&stc=1

...and the pizza I burned while writing this thread:
http://www.o-r-c-a.org/forum/attachm...tid=3906&stc=1
:cry2:

How are you keeping the kalk stirred up? Once it settles what good is it?

I was waiting for this question to come up. It turns out, my kalk is staying saturated just fine without having to be stirred. Because of the small, pressurized hole drilled in the bottom of the cap, when I turn on my RO top off, the water shoots through the stem and is reduced through the drill hole in the cap, increasing the pressure. Apparently, this is all the 'stirring' that needs to occur. My output water consistently has a Ph of 12 indicating full kalk saturation. Cheers!

Sounds interesting. I think I might attempt to do the same thing using my ATO. Seems cheap enough. :)

Man your full of knowledge. Thanks for joining :)

I have been keeping saltwater tanks for years, I've owned my own coral propagation farm, and now I'm just a grad student/overzealous aquarium hobbyist. The purpose of these forums is to spread knowledge, right?

So here are some pics of the pH in different solutions adding validity to the effectiveness in the Kalk reactor at work.

Here is the pH of one of my marine tanks:
http://www.o-r-c-a.org/forum/attachm...tid=3909&stc=1
Here is the pH of one of my freshwater tanks:
http://www.o-r-c-a.org/forum/attachm...tid=3910&stc=1
And here is the pH of water collected directly out of the ATO float valve coming from the pH (a pH of 12 indicating a fully saturated kalkwasser solution):
http://www.o-r-c-a.org/forum/attachm...tid=3908&stc=1

I need to pick up the cannister and plumbing supplies but wanted to make sure my scenario will work fine...I am using the JBJ ATO. My idea is to let that stay in place and work as it always has. The output from the pump will now be diverted from the tank to the input of this cannister and the output of the canister then sent to the tank? Using the ball valves I will have control over how much water goes through the kalk vs how much skips the kalk and goes straight to the tank. Do I have it right?

Let me know if the Float valve crusts up and sticks.. thats only thing i see that may be an issue.
great job.. I find my Kalk vessel stays saturated once mixed for months. I make a 2 month batch of 50 gallons at a time and it is drawn off by a Doser pump at a set amount per day. from the bottom of the vat, which fills/matches my evaporation rate closely. Also watch for back siphoning where it enters the Tank area. With he check value that should be ok though.

Eg8r210 - The JBJ ATO system you have should work fine when plumbed accordingly. You have the idea of the valves correct. The only issue that I'd worry about running into with that set up is line pressure before the canister holding the kalk. My RO output before the canister has plenty of pressure to shoot through the stem, out the drill hole, and stir the kalk before exiting via float valve into my sump. I wonder how much pressure the JBJ system has? There is always a way to make everything work with some ingenuity, so let me know how it works and if you run into any problems! I'll be glad to help.

Jim28fl - Thanks for the comment! I see the methodology as far as, "All kalkwasser reactors must have a stirrer to keep kalk saturated in solution..." as a bit of a folly and frankly, a bit untrue. I think it is a way to drum up demand for a grossly overpriced $200-$400 special-purpose reactor. As evidenced by my pH tests and your firtshand experience, stirrers are really an accessory and not a requirement for these kalkwasser applications. I will keep you informed of the potential kalk crust build up on the float. So far, so good, as I have no seen any build-up inside the canister nor anywhere on the float valve. I'm keeping my fingers crossed! If it does become an issue, then I'll just have to install an electronic switch and solenoid to control the top off. Not a big fix if I have to do it.

Also note worthy I usually dump in a whole bag of Kalk mix and stirred it tested the Ph and on a well calibrated meter and my RODI systems final product water, it settled at about 12.41 at 72 degrees. I have yet to ever see it go higher. I hear its best to actually measure it with a salinity meter. Something like 11.1 Micro simens " VS 53.0 =SW @1.026" i think it should be, but I never tried yet. I now use this PH=12.41 as a base line when i refill the vat and stir to decide if i need to add more powder in the vat or if there is enough left over from the last batch to saturate the next round of 50 gallons mix.
You do not need to fully saturate your Kalk mix BTW. Some folks use a half strength batch if its a fish only or softies tank and find that is more than enoughtto keep up the parameters.

I run it as much as it can hold with out getting into the adding vinegar thing which further boosts it a bit. Read up on that before you try it please.

I alternate using a bag of Mrs wangs From walmart "pickling lime" mix and the Kalk+2 powder from the fish stores. i have not had issues with the Mag lvl so i have opted for the MRs wants stuff which doesnt have the added mag n Strotium in it. and cost less. Kalk in your Top off water is always a good thing IMO and very rarely could not be utilized by your system in a good way.

But you need to dose it slowly and often thru out the day. Not a good idea to dump in 1 gallon a day for evaporation. That would cause a huge Swing. Which is bad.

50
Jim28fl:

I run it as much as it can hold with out getting into the adding vinegar thing which further boosts it a bit. Read up on that before you try it please.
I'm not sure what you are referencing with the adding vinegar thing? Is this what you suggest I read into?

But you need to dose it slowly and often thru out the day. Not a good idea to dump in 1 gallon a day for evaporation. That would cause a huge Swing. Which is bad.
Thanks for the pointers. My RO is on all day long so it is added slowly.

53
The '50' in red above your name is a typo...not sure where that came from lol.

You can increased the potency of your Kalk by first adding an amount of distilled white vinegar to the water then adding the Kalk powder. "commonly called Pickling lime or lime ' something about C02 release. its minimal and it also is a carbon source to some degree i believe. Not many folks do it. It pushes the Kalk past supersaturation a bit somehow by boosting the Ph of the water by pushing out all the CO2 before the powder is added. Thats as much as i remember. But it does provide a bit more kick.. most folks are fine with saturated Kalk as is it. The vinegar is to much additional complication for the added benefit from all the posts I read. I would search "Adding vinegar to Kalk mix to increase potency" in your browser if your interested.

I personally seal up my mix tightly after the stir because i have read it can loose some of its bang if stirred a lot or open to air because C02 enters the water and fizzles it out to some extend. Again i think its minimal. Just don't leave a circulation pump on it 24/7 for sure. That will ruin it after a few days of being open to the air.

This is a reef central post about it...

http://www.reefcentral.com/forums/sh....php?t=1952263

Quote:

---

Originally Posted by Jim28fl

You can increased the potency of your Kalk by first adding an amount of distilled white vinegar to the water then adding the Kalk powder. "commonly called Pickling lime or lime ' something about C02 release. its minimal and it also is a carbon source to some degree i believe. Not many folks do it. It pushes the Kalk past supersaturation a bit somehow by boosting the Ph of the water by pushing out all the CO2 before the powder is added. Thats as much as i remember. But it does provide a bit more kick.. most folks are fine with saturated Kalk as is it. The vinegar is to much additional complication for the added benefit from all the posts I read. I would search "Adding vinegar to Kalk mix to increase potency" in your browser if your interested.

I personally seal up my mix tightly after the stir because i have read it can loose some of its bang if stirred a lot or open to air because C02 enters the water and fizzles it out to some extend. Again i think its minimal. Just don't leave a circulation pump on it 24/7 for sure. That will ruin it after a few days of being open to the air.

This is a reef central post about it...

http://www.reefcentral.com/forums/sh....php?t=1952263

---

190
Very interesting. I think I'll just stick to what's working for me, though. I will definitely read more into it in the meantime.

21
***Update***

The DIY Kalk Reactor is working great! I have no clogs, leaks, or problems with it at all. I highly recommend the build for a cheap way to dose Kalk.