Kalkwasser Stirrer Intro/Setup

[mfollen]

Hey reefers!

I'm about to setup a K1 Avast Kalk Stirrer. I've never dosed kalk before and plan on dosing through a dedicated dosing head, not ATO.

I plan to code the GHL to run the stirrer for 15 minutes every 2 hours, with the pump dosing kalk after.

I'm not sure how much kalk solution I should put in the reactor chamber. Is it only what the package lists amount per gallon of top off water? I'm not sure if that amount is what you put in for the duration of the product use until cleaning every few weeks / a month or if it's more.

For example, I estimate that I lose a little over a gallon a day in evaporation a day on my 180. Alk/CA demand is low as its a new tank.
BRS recommends for low demand - 1/2 teaspoon per gallon of top off water.

So do I add a total of 1/2 teaspoon in my reactor for the full month of use before cleaning out? Or do I multiply the gallon of evaporation a day by the 1/2 teaspoon over the period of use?

Thank you - total Kalk newb here...

 

[rkpetersen]

IMO It's best to be dispensing fully saturated kalkwasser. This is easiest to create and remains consistent.
The stirrer is there to make sure that the kalk solution remains saturated.
The solubility of calcium hydroxide in water is actually pretty low, about 2 teaspoon per gallon of freshwater.
So, put enough in your reactor and mix well, so that most of it dissolves, but there's still some undissolved kalk on the bottom.
This will ensure that the solution is saturated and stays saturated.
The amount of undissolved kalk left on the bottom isn't critical, as long as it isn't so much that it interferes with the stirrer.
If your evaporation is 1 gallon a day and you're replacing it all with kalk, that would be about 2 teaspoons of kalk usage per day.
After stirring, give the undissolved kalk powder time to settle out before dispensing the clear solution. You don't want solid particles in the effluent.

If you want to start with unsaturated kalk, to be on the safe side, you can.
But the concentration of the kalk will be a lot more variable from moment to moment and day to day.
For the BRS recommendation and your evaporation of 1 gallon a day, you'd have to add another 1/2 tsp kalk powder every day.
If you tried to add a month's worth in advance, and then stirred it up, you'd wind up with the saturated solution.

 

[mfollen]

This is extremely helpful and clearly laid out. Thank you so much @rkpetersen !!


Would 15 tsp or tbs be ok to leave in the alk reactor over a month? Wouldn’t the fully saturated solution be more potent week 1 vs week 4?

And is it ok to leave the solution on the bottom, unstirred every 2 hours? Or should the stirrer be running 24/7?

Lastly to confirm: I take the daily recommendation and multiply that by the duration I plan to run the reactor before either topping off with more kalk powder or cleaning the unit.

Thank you again and sorry for the questions!!! I don’t want to kill my fish and coral! That would be so devastating.

 

[rkpetersen]

This is extremely helpful and clearly laid out. Thank you so much @rkpetersen !!


Would 15 tsp or tbs be ok to leave in the alk reactor over a month? Wouldn’t the fully saturated solution be more potent week 1 vs week 4?

Fully saturated solution is always the same potency. As long as the solution is well mixed and there is undissolved kalk on the bottom, the solution will be saturated.
At a gallon of saturated kalk a day, you'd be using up to 60 teaspoons or about 1 1/4 cups of the powder per month.

The only complicating factor is that, on contact with CO2 in air, some calcium carbonate will inevitably precipitate out and will not redissolve.
By visual inspection, you can't tell this apart from the undissolved kalk; they are both white powder.
But eventually, most of what you think is kalk on the bottom might just be CaCO3 instead.
This usually isn't a huge issue in reactors though because the surface area where the solution contacts air is relatively low (worse in some ATO reservoirs.)
So it's still a good idea to clean out your kalk reactor now and then. I do mine every 6 months, could be more often .

And is it ok to leave the solution on the bottom, unstirred every 2 hours? Or should the stirrer be running 24/7?

Definitely not 24/7. Every 2 hours is probably still overkill. Once it's mixed, the kalk that has gone into solution won't precipitate back out. (Not exactly true, but close enough.)
And remember, the saturated solution should be clear or slightly opalescent when it's dosed, not white and cloudy.

Lastly to confirm: I take the daily recommendation and multiply that by the duration I plan to run the reactor before either topping off with more kalk powder or cleaning the unit.

Thank you again and sorry for the questions!!! I don’t want to kill my fish and coral! That would be so devastating.

If you put a larger amount in, you'll be using saturated kalk, and have to adjust your dosing accordingly.
I don't measure the amount of kalk I put in the reactor that precisely.
About 1/8 cup or so every 3-4 days typically, or more if I notice a drop in the average pH range.

Since you're on a doser not tied to an ATO, you could easily start with less kalkwasser per day and manually make up the rest with plain rodi.
Make sure that alk and pH don't change too quickly. Then gradually increase the kalk over a week or so until you're just using kalk.

 

[mfollen]

Fantastic. You helped me not going into this blind. I couldn’t find anything researching, so a possible catastrophe averted. Hopefully! If I don’t screw it up

Can’t wait to no longer dose 2 part by hand

 

[rkpetersen]

Fantastic. You helped me not going into this blind. I couldn’t find anything researching, so a possible catastrophe averted. Hopefully! If I don’t screw it up

Can’t wait to no longer dose 2 part by hand

Awesome! I hope it goes well and you're happy with the results.
You'll have to keep magnesium and trace elements in mind, as kalk doesn't replace these.
But if you do water changes and/or don't have a lot of growing stony corals, it should be a minor issue.