DIY Kalk Stirrer flow not working as expected. Please Help!

CJ Monty · Dec 7, 2021

I built a Kalk Stirrer and I noticed that it takes about 100 ml to start to get water to flow out the outlet. Once the pump turns off 100 ml comes out. For some reason the stop equilibrium is 100 ml less than what it takes to get the flow going and no idea why. I have not owned a kalk stirrer before but I assume they are more precise than this since most people run a dosing pump with it.

I pump water into the bottom of the container. I have the outlet towards the top of the container with a little piece of tubing into a elbow. Outside the container a use a tee instead of an elbow to prevent a siphon. Any thoughts on what is wrong with what I am doing?

2una · Dec 7, 2021

Try removing the inside down facing piece.
I'm guessing it is only breaking siphon once it gets to the end/bottom of that inside tube.
Remove that & it will then break siphon closer to the outlet.
Then again maybe i've not had enough coffee.

Edit:
Or try twisting it around so its horizontal & the same level as the outlet

CJ Monty · Dec 7, 2021

2una said:
Try removing the inside down facing piece.
I'm guessing it is only breaking siphon once it gets to the end/bottom of that inside tube.
Remove that & it will then break siphon closer to the outlet.
Then again maybe i've not had enough coffee.

Edit:
Or try twisting it around so its horizontal & the same level as the outlet

OMG thank you so much. I removed the elbow and it works a lot better! I have seen other designs with that. Not exactly sure what the deal is but problem solved!

Thanks again!

RocketEngineer · Dec 9, 2021

The elbow inside is there because a crust forms on the surface of the kalk where the liquid interacts with air. This crust doesn’t dissolve and could clog small tubing so you may want to reconsider that internal elbow. Using larger outlet tubing may be a better solution.

CJ Monty · Dec 9, 2021

Thanks, I did do that the other night. I am still running into an issue though. I add 1ml at a time using a gradual cylinder (for this experiment) to displace the water. I keep doing that and nothing comes out. Eventually water does flow and 37 ml flow out. I can reproduce that over and over again. Is there momentum at play here or something else?

Wonder if this is of real kalk stirrer work this way anyway. 1ml in for 1ml relying on displacement seems too precise to me.

YOYOYOReefer · Dec 9, 2021

Its the surface tension acting on the "skin thin"top slice of water, its taking what your calling momementum to overcome. 1 ml in eventually nets 38 out 100 ml(all at once) in would net 137 out if im following your experiment right.

CJ Monty · Dec 9, 2021

YOYOYOReefer said:
Its the surface tension acting on the "skin thin"top slice of water, its taking what your calling momementum to overcome. 1 ml in eventually nets 38 out 100 ml(all at once) in would net 137 out if im following your experiment right.

Sorry I did not explain properly. At equilibrium nothing comes out until I add ~37ml due to surface tension. At that point all 37ml flows out. This makes perfect sense to me.

Is this behavior expected for a kalk stirrer that you purchased or they more accurate than this for some reason?

2una · Dec 9, 2021

CJ Monty said:
Wonder if this is of real kalk stirrer work this way

I run my rodi thru my stirrer via a dos - i just calibrate the dos to what comes out the outlet pipe.

YOYOYOReefer · Dec 9, 2021

i run rodi thru litermeter pump thru kalk stirrer and also calibrate based off the output at the sump out of the kalk reactor

CJ Monty · Dec 9, 2021

How much do you (@YOYOYOReefer & @2una) dose at one time and how often? Looks like my min dose would have to be ~37ml which I do not know if is a big deal.