pH of Full Strength Kalk

Mohammed

New member
Hi Guys,

I have a kalk reactor which I want to incorporate into my system.

On my previous system I had a stirrer type which I topped with about 2 tablespoons of kalk powder weekly and cleaned out every 3 months, to ensure the stirrer didn't jam or burn the stepper motor, as you can imagine I was wasting quite a bit of kalk as I had no idea if the reactor always had max saturation or the sediment was waste or perfectly good kalk.

I now have a kalk reactor with a re-circulation pump and was wondering how often do you guys generally top up the reactors and with how much kalk.

With reactors its difficult to reduce the saturation of your kalk unless you know a few variables which I'm too lazy to do the math on right now and will require keeping track of RO chamber and the amount of kalk in the reactor.

Is there any way to test the maximum saturation of my kalk, perhaps by pH. Is the pH of max saturated limewater the same or does it vary if the amount of kalk power added is over what it can saturate too. Basically is the pH of a gallon of ro with 5 teaspoons of kalk the same as 1 gallon of ro with say 10 teaspoons, both will be at max saturation with some settlement.

I want to ensure my reactor is at max saturation rather than eyeball the sediment and assume its at max that way I can add kalk as needed rather than clean out the reactor of perfectly good kalk.

My plan is to use kalk on a timer for about 90% of the evap and an atu for the shortfall. How will I set this up?

Sorry for all the ramblings.
 
Our pH meters generally don't read accurately at the pH of saturated limewater, which should be at about 12.5. You could make a small sample of saturated lime with a cup of water and a teaspoon of lime, and measure the pH of that with your meter, and then measure the water from the reactor.

Alternatively, a conductivity meter that can read in the 10-15 mS/cm<sup>2</sup> range should do the job.

This article has some numbers:

http://reefkeeping.com/issues/2005-01/rhf/index.htm
 
I try to add fresh Kalk to the reactor every week and clean out every other week (or monthly at the longest). I think the Ca(OH)2 reacts over time and what is left in the bottom is insoluble- thus what you think is good, probably isn't. I find over the course of 2 weeks without adding any fresh stuff that my alk (and pH) will start to drop and I have to add 2 part to make up. Still plenty of white stuff being mixed in the bottom of the reactor. I'm using an Avast reactor and the mixer runs 24/7 so not a result of being under mixed.

Mine is hooked up to my ATO (run on a ReefAngel controller) so all make up water is Kalkwasser.
 
Thanks michaelg, that really clarifies things. How much kalk do u add to your reactor weekly?

Perhaps that will give me a starting point.

Thanks
 
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