Calcium Hydroxide... must it be stirred?

[MeuserReef]

I have an old 10" filter housing that I used on my previous tank as a Kalk Reactor. There was a magnetic stir bar inside of the filter, and a stir plate underneath. 6 times a day, the stir plate would turn on and completely mix the Ca(OH)2 into a milky solution. Roughly 3 hrs later, my solenoid-controlled ATO would kick on and feed fresh RO/DI water into the Reactor (at the bottom of the canister), pushing saturated water out of the top of the canister and into my sump.

Heres the old setup: (in a fully "milked" state)
http://img.photobucket.com/albums/v708/Original_Tarheel/RODIKalkReactor.jpg

Stir bar buried in Ca(OH)2 (once the "milk" has settled)
http://img.photobucket.com/albums/v708/Original_Tarheel/KalkReactor.jpg

Heres my question,...

Is it really even necessary to stir the Calcium Hydroxide?

I would like to use the same filter housing, yet do away with the stir bar/plate all together.

If I filled the bottom of the canister with Calcium Hydroxide (to about 3" deep) and delivered the fresh RO/DI water so that it was forced up through the kalk powder, would it still saturate the water?

I simply dont have room under my stand for the stir plate (wife kicked my reef hobby out of HER laundry room.. so Ive got to put the Ca(OH)2 Reactor under the stand :furious:

[Billybeau1]

The second picture your posted, what is that canister ?

[MeuserReef]

<a href=showthread.php?s=&postid=14610363#post14610363 target=_blank>Originally posted</a> by Billybeau1
The second picture your posted, what is that canister ?

Its an up close shot of the bottom of the clear 10" filter housing in the first pic.

Anyone have any thoughts about a non-stirring kalk reactor?

[tmz]

My thought is it must be stirred in a reactor. The undissolved kalk at the bottom must be stirred into the solution periodically. Since the reactor itself has al ow water volume it can only hold a small amount in solution at one time. Without stirring I doubt enough would dissolve to give you very much strength.
I use a large still resevoir( a 32 gallon brute garbage can) and it only needs to be stirred when initialy filled about once a week . Once the kalk stirred into solution it does not need to be stirred again.However, excess kalk at teh bottom of the can will for the most part just sit there untill the next stirring.

[Randy Holmes-Farley]

Check the recycling label on the cannister If it is polycarbonate (as is often used for clear plastics), then it is not a good choice as limewater will degrade it and it may eventually crack and leak.

Lime does need some sort of mixing to get it to dissolve, but forcing the water through it may work initially, at least until it dissolves a channel though it and then flows through that opening like a pipe.


You can see if it is working by measuring the conductivity, or less precisely, pH. If you choose to do these, I'll describe how.

[virginiadiver69]

I was about to post this same exact question when I saw yours Meuser.
I just set up a GEO reactor and worry that I may end up dosing a slurry if it's mixed.
Randy...I've been thinking of tapping the lid of the reactor to insert a pH probe so I can set my controller up to mix just when pH falls below a set point.
Is there enough of an accuracy difference to warrant using conductivity rather than pH?
I won't be able to control via conductivity.

[Randy Holmes-Farley]

You'll have to be careful how you calibrate it, and a drop of 0.3 pH units is about 50% of saturation. I've not heard of anyone doing this, but it might work. :)

[MeuserReef]

Good info. Thanks for the help Randy. I believe the plastic is polycarbonate so I will certainly watch it for signs of cracking. Ive got some scrap acrylic tubing that I might use to make a new reactor.

[slow_leak]

I'm sure that canister is not acrylic for what it's woth. I'm in chemical industry. You might end up with calcium salts of degraded plastic in your tank. Use a glass jug atleast.