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View Full Version : how often did u change the kalk solution from the kalk reactor?


chercm
10/16/2009, 08:13 AM
pls advice

mm949
10/16/2009, 11:24 AM
once the pH drops below 12....

Randy Holmes-Farley
10/16/2009, 12:05 PM
You can track tank alkalinity or reactor effluent conductivity (10.3 mS/cm or so is saturated), or less precisely, the pH of the effluent.

A drop of 0.3 pH units from the level for saturated limewater is about 50% saturated.

I would probably not advise focusing on an exact value most of the time. Strictly speaking, pH 12 is only about 30% saturated, but the calibration at this pH is likely poor. So maybe compare the effluent directly between truly saturated limewater (say, 2 teaspoons in a CUP of RO/DI) and the effluent. :)

9501gle
10/16/2009, 02:39 PM
I change mine every 2 months, ph holds steady, dont know if this is optimum but works well for me.

chercm
10/16/2009, 07:44 PM
i am using deltec KM500 kalk reactor

vegaskid11
10/16/2009, 10:36 PM
I have the same reactor. I do just as Randy has said. I asked him the question a couple years ago. I just put two teaspoons of fresh kalk in a cup of rodi then use my meter. It normally measures 12.6 for me so I only remeasure with it about every 6months when I recalibrate my meter. I then unplug the reactor and lift the lid a bit and stick my meter in the top of the reactor about 2" down. After about a week for me (500 gallon) it drops to 12.3 or so and I throw a couple more scoops of kalk in right on top of the old. Every 5-6 weeks I clean the whole reactor. hth

tegee
10/17/2009, 09:59 AM
Can you simply keep adding kalk directly to the reactor (i.e.: top off) every time the ph of the effluent drops? Because that is what I ha.ve been doing for the past 8-months and it has been working. Or when do I completely have to dump the kalk unit and start from scratch?

Randy Holmes-Farley
10/17/2009, 11:20 AM
At some point you'll have a lot of crap that you'd want to wash out rather than have it take up a lot of space and risk being delivered to the tank accidently. Much of it will be calcium carbonate, which is no big deal, but some may be less desirable metals and such.

tegee
10/17/2009, 01:25 PM
At some point you'll have a lot of crap that you'd want to wash out rather than have it take up a lot of space and risk being delivered to the tank accidently. Much of it will be calcium carbonate, which is no big deal, but some may be less desirable metals and such.


but if it is still mixing in a slurry when the pumps comes on 4-times/day for 2-minites each time is that not a sign of it still being usable kalk? Nothing it caked up and/or building up inside the reactor. So what signs do I look for?

Randy Holmes-Farley
10/17/2009, 01:41 PM
All of the slurry may be insoluble calcium carbonate particles, so no, the fact that it is a slurry does not imply available calcium hydroxide.

pH of the effluent or conductivity of it, or tank or effluent alkalinity are ways to judge.

joao junior
10/17/2009, 02:56 PM
sorry,randy can i use this for measuring the conductivity
http://www.premiumaquatics.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=HI-PRIMO&Category_Code=Hanna
thanks

Randy Holmes-Farley
10/17/2009, 03:45 PM
No. You need to read up to 10.3 mS/cm, which is on the order of 6,000 ppm TDS. That one only goes to 2,000 ppm TDS.

joao junior
10/17/2009, 04:19 PM
randy when i buy one o theses??thanks.

Untamed12
10/17/2009, 08:56 PM
I went through this learning with the assistance of Randy some time ago...(thanks again) Now, I can tell when my Kalk reactor needs more Kalk because it no longer stops my pH from falling overnight. My controller graphs begin to show pH dropping overnight, so I know that my Kalk has gone weak.

IME, that takes about 10-12 days. I can add additional Kalk about 4 or 5 times before there is so much stuff at the bottom of the reactor that I just dump the entire thing.

I only add Kalk at night.

tegee
10/18/2009, 08:07 AM
With that said, what should the ph of the effluent be? And I started the kalk reactor up in May/June time frame, is it time to dump the entire reactor and recharge? I use it 24/7 with with ATO.

Thanks a bunch and great info.......

Randy Holmes-Farley
10/18/2009, 08:22 AM
Saturated limewater has a pH of 12.534 at 25 deg C. :)

What Your Grandmother Never Told You About Lime
http://reefkeeping.com/issues/2005-01/rhf/index.htm

from it:

Limewater that is saturated with calcium hydroxide has a pH of 12.54 at 25ºC. It is actually recognized as a secondary pH standard. The pH is substantially higher at lower temperature (12.627 at 20ºC and 13.00 at 10ºC), and lower at higher temperature (12.289 at 30ºC; 11.984 at 40ºC). Saturated limewater has a conductivity of about 10.3 mS/cm at 25ºC, and contains about 808 ppm of calcium and 40.8 meq/l of alkalinity. Slightly more calcium and alkalinity dissolve at lower temperatures, and less at higher temperatures. Of interest to chemists, a large fraction of the calcium in saturated limewater is present as the ion CaOH+, with the remainder being Ca++. The CaOH+ will instantly dissociate into Ca++ and OH- upon its addition to aquarium water.