Kalkwasser Reactor

[RussM]

With work at a seasonal low, I've had some time to putter in the garage.... I have two projects in the works, and here is the first: a magnetically-stirred kalk reactor.

I have no dry space available inside my stand, so the reactor has to fit in or above the sumps. I have 3 interconnected sumps. Since the reactor may sit in water, the mag-drive prime mover has to be on top of the reactor, unlike the traditional mag stir reactors where the motor is beneath the unit.

The reactor chamber is 6"x11.5". RO/DI water is pushed into the reactor by an Aqualifter, drawn from my ATO reservoir. Supersaturated kalkwasser is displaced by the pure water feed and will flow into the opposite end of the sump from where the AquaController probes are. Dosing will be controller by the AC3 with time of day, dosing amount/time, and pH factored into the AC3 programming. Periodic stirring will be controlled by a standard lamp timer, perhaps 5 minutes 2x daily.

The stirring action is provided by a 5-RPM motor magnetically coupled to the stirrer shaft & impeller; a total of (16) N43 neodymium magnets were used (8 each for the driver and driven plates.)

With the exception of a few stainless steel screws and the John Guest fittings, all components were obtained from various sources in/around San Diego: Murphy's Surplus, Industrial Liquidators, California Electronics, the scrap bins at Ridout Plastics, or parts I already had on hand. Total $$$ investment was quite low! The acrylic cylinder was only $5. Time investment, on the other hand, was significant... I really took my time. I mainly have woodworking tools... table saw, compound miter saw, band saw, drill press, router, etc, all of which were used. I used the drill press on its highest speed as a light-duty vertical mill to make things like the o-ring groove in the bottom flange, cutting smaller circles, etc. (professional machinists, try not to cringe too much!)

The parts ready for assembly after cleaning and final polishing...
http://www.michelfamily.net/pics/!kalkreactor_disassembled.JPG
The bottom really didn't need to be removable, but I wanted to make the flanges just for the experience.

The mag-drive...
http://www.michelfamily.net/pics/!kalkreactor_magdrive.JPG

The motor mount...
http://www.michelfamily.net/pics/!kalkreactor_motormount.JPG

The assembled mag-drive unit...
http://www.michelfamily.net/pics/!kalkreactor_drive.JPG

After thorough leak and functional testing, final assembly, a vinegar bath, and initial loading with Mrs. Wages & RO/DI...
http://www.michelfamily.net/pics/!kalkreactor_assembled.JPG
The gizmo in the lower right of the pic above is a weighted intake; it's weighted to ensure that the RO/DI water intake line stays at the bottom of the ATO reservoir.

The reactor in operation... you can see the little hump of kalk being pushed by the stirring impeller.
http://www.michelfamily.net/pics/!kalkreactor_stirring.JPG

The power cord for the motor was soldered/heat-shrinked after the pics were taken... no more wire nuts.

[RussM]

ARGH! Can't seem to get the images to display inline.

[NanoReefWanabe]

i guess the length of the shaft limits the amount of Kalk you can put in the reactor as i cant imagine the propeller and shaft would have enough umph to overcome the thickness of wet saturated kalk powder/ paste...how often do you figure you will have to refill it?

[RussM]

The geared motor has plenty of torque, and the mag-drive will handle a fair amount of resistance before it stalls/skips, so I imagine I could load it up with quite a bit more lime - I should test that to see if it stalls with lime at a couple of inches in depth. Even if I have to recharge it every couple of weeks, I won't complain.

[One Dumm Hikk]

I am guessing that the purpose of the magnet drive is to keep the kalk out of contact with the pump? I have been contemplating building a Kalk reactor and it has me wondering what the benefits/drawbacks of magnet drive and just having a pump plumbed into the reactor to keep it mixing?

["Umm, fish?"]

I can try to get them in-line for you:

http://www.michelfamily.net/pics/!kalkreactor_disassembled.JPG

http://www.michelfamily.net/pics/!kalkreactor_magdrive.JPG

http://www.michelfamily.net/pics/!kalkreactor_motormount.JPG

http://www.michelfamily.net/pics/!kalkreactor_drive.JPG

http://www.michelfamily.net/pics/!kalkreactor_assembled.JPG

http://www.michelfamily.net/pics/!kalkreactor_stirring.JPG

Thanks for the thread! I think I might have to build one of these.... :)

Edit: Sorry. The image tags are right, but all I get are URLs, too.

[RussM]

<a href=showthread.php?s=&postid=13824322#post13824322 target=_blank>Originally posted</a> by One Dumm Hikk
I am guessing that the purpose of the magnet drive is to keep the kalk out of contact with the pump? I have been contemplating building a Kalk reactor and it has me wondering what the benefits/drawbacks of magnet drive and just having a pump plumbed into the reactor to keep it mixing?

Yes, the magdrive keeps the wet parts wet and the dry parts dry.... without messing around with seals. The two magnet plates are separated by a 3/32" thickness of polycarbonate sheet (stronger than acrylic) and a very thin nylon washer on either side of the plate (to minimize friction/drag)

A recirculating pump would have been much easier to do, that's for sure. But a recirc pump tends to make a big cloud of kalk, which needs to settle out before dosing - ideally, as I understand it, it is best to dose clarified kalkwasser - without a lot of suspended particulate.

The stir rate in my contraption is enough to agitate the sediment at the bottom of the reactor, but doesn't create much turbulence to make a big cloud of suspended matter. It's been sitting on my workbench all day running continuously as a test, and the top few inches are fairly clear. based on this, I could probably just leave the stirring running constantly if I wanted to.

[One Dumm Hikk]

Thanks Russ. And yes, you have to let the suspended particulate settle out and only does with the clear fluid left on top. I have an idea on how to get around that part of a kalk reactor but I have to test/tinker with it. The magnetic drive appeals to me because of that very issue.

[RussM]

There's a thread here on RC somewhere in which people were debating whether it's necessary to have stirring or mixing at all in a kalk reactor. I just went with the middle-of-the road approach.

[NanoReefWanabe]

i just read in this months Marine Fish & Reef, that there is no need to let the water settle before using but you should use ph monitors on the effluent...something along the lines it allows 10% supersaturation...i could scan and insert the excerpt from the mag...the article is called "Getting Buff ~ 7 ways to dose limewater"

[One Dumm Hikk]

I think I will see if I can find a copy locally of MF&R. I would be interested in reading the article. The person that taught me said that I should let it settle and only use the clear fluid on the top (supernatant). Will give me some insight on being able to ask him about a possible different way of dosing it.

Along with a pH monitor, wouldn't you want some way to turn it on/off if the pH got out of whack?

[RussM]

Randy Holmes-Farley describes dosing of milky kalkwasser as a viable option, but he does point out some drawbacks:

"Dosing milky limewater, to get more lime into the aquarium than is available in clear, settled limewater. A drawback is the delivery of impurities in or on the solid particles, and the possibility that some solids may interact with organisms before they dissolve."

Full article here (http://reefkeeping.com/issues/2005-01/rhf/index.php)

[dattack]

RUss, where you get the lid for the reactor?

[RussM]

I found it mounted in the center of a 2'x2' piece of dark gray 1/4" PVC sheet. I think it was for some sort of clean-out access. It was at Murphy's Surplus in El Cajon. $4 for the whole assembly:)

[RussM]

I found some time to add more Mrs. Wages, bringing the total depth of solids to around 3.5". The mag-drive coupling is holding strong.. plenty of torque! It actually stirs better with more lime in it.

[MeuserReef]

I think the underscore is whats messing up the IMG tags?

[stugray]

RussM,

Dont you worry that the magnets will corrode?

I know some magnets are coated in copper then nickel.


I vote for the "no need to stir" mode.

I did a DIY Kalk reactor from one of these I had laying around:


http://www.f3images.com/IMD/250/AP4111/AP4111_1.jpg

I drilled & tapped the top & bottom & replaced the nipples with JG fittings.

I just fill it up & it takes a few months for the Ms Wages to disappear.

I use it in an up-flow mode & seems to work fine being gravity fed from upstairs.

I use one of these JG needle Valves to control the drip rate:
http://www.usplastic.com/images/products/valves/SKU/22148.jpg

Stu

[RussM]

<a href=showthread.php?s=&postid=13874534#post13874534 target=_blank>Originally posted</a> by stugray
RussM,

Dont you worry that the magnets will corrode?

Nope... the magnets are 1/4" thick, the acrylic discs are about 5/16"; when I press-fit the magnets in their holes, I centered the magnets, leaving a 1/32" recess on either side. A dollop of Weldon 40 was placed in each hole on one side of the discs; when that set, I did the same for the other side. After a day of curing time, the little humps of Weldon 40 were sanded flush. Even on the dry side plate, the magnets are sealed. In the pic, it does look like the magnets are exposed, doesn't it?