DIY Pressurised Kalk Reactor/Stirrer

Borat · Oct 8, 2021

OK, I ordered a non-return valve (aka check valve) that will be inline between ATO container and Kalk reactor..

So when peristaltic pump pumps Kalk water into mixing chamber and the tank in this very moment does not need RO water top-off, the water will be pushed back from mixing chamber into Kalk reactor..

Borat · Oct 8, 2021

Today I changed the stirrer bar into a cross-bar: no more bar displacement and I can run PWM fan at high speeds..

..and added some shut-off valves

laverda · Oct 16, 2021

I think you will find you need to add much less kalk then your planning depending on the size of your system. I would move the pump to between you RO source and pump into the kalk container. Also there should be no need for a separate mixing container.

Borat · Oct 16, 2021

laverda said:
I think you will find you need to add much less kalk then your planning depending on the size of your system. I would move the pump to between you RO source and pump into the kalk container. Also there should be no need for a separate mixing container.

Thanks. Kalk residue (however small) seem to block the float valve if I don't have a sediment chamber.. I tried removing it but it wasn't a good idea, I found out - so I moved it back but reduced it in size..

No - pumping into Kalk container would not work: the line from RO container and tank most of the time is closed- by the float valve in the sump (unless water evapororates and it opens to let RO water in). As per current design, if the top-off RO water is not needed (at some point in time - float valve is closed) - the water recirculates back into Kalk reactor..

Borat · Oct 16, 2021

Smaller sized sediment chamber:

Borat · Oct 16, 2021

laverda said:
I think you will find you need to add much less kalk then your planning depending on the size of your system. I would move the pump to between you RO source and pump into the kalk container. Also there should be no need for a separate mixing container.

How much kalk do you dose in your system? I have a 420L system and dose 2ml/min (24/7), which is about 3L/day, this is pretty much the maximum I can add given average evaporation rate of 1% per day..

laverda · Oct 18, 2021

Sounds like your running your stirrer and feed pump constantly.

Borat said:
How much kalk do you dose in your system? I have a 420L system and dose 2ml/min (24/7), which is about 3L/day, this is pretty much the maximum I can add given average evaporation rate of 1% per day..

That is a lot considering you said you goal was primarily to raise PH and not increase your Alk or CA level.
I dose much less and only at night to help keep the PH higher and steady.

Borat · Oct 19, 2021

laverda said:
Sounds like your running your stirrer and feed pump constantly.

That is a lot considering you said you goal was primarily to raise PH and not increase your Alk or CA level.
I dose much less and only at night to help keep the PH higher and steady.

One needs to dose quite a lot to raise PH... your personal target to raise it is probably marginal (0.1PH)? Mine is quite chronically low - so I need a constant boost. I also have an Alk monitor that dumps 500ml of PH4 used water each day into tank - that contributes to low PH issues.

laverda · Oct 19, 2021

If it works for you that is all that matters. I am raising my Ph .2-.3
I dose for 5 min every 30 minutes for 12 hours each night.

reef_ranch · Oct 19, 2021

You have mad skills! No leaks?

Borat · Oct 19, 2021

acesq said:
You have mad skills! No leaks?

No mad skills here

- just a bit of experience I built over time by doing various projects.. No leaks either - if you know how to make reactor chambers - they will probably be as reliable as commerically made ones if not better..

I made a DIY CaRx earlier this year- learnt a lot of lessons as a result and building this reactor chamber + stirrer was very easy..

Project CaRx: DIY Calcium Reactor + DIY Controller + DIY Peristaltic Pump + DIY ALK Monitor

Hey folkes, 2 large DIY projects completed this year and now I am sitting idle.. What should I do next? The target for my tank is to slowly grow into an SPS dominant system. I already have 3 palm sized plating easy-going monties and have to dose about 100ml of alkainity solution daily (100mg...

ultimatereef.net

Borat · Oct 20, 2021

After 10 days the magnetic stirrer bar seemingly stopped.. but after careful inspection (listing to the reactor) I realised that the stirrer bar is still spinning inside, just not being visible under Kalk layer. I let it run "as is" and after a day I noticed a small crater in Kalk that the stirrer bar formed. Now the crater became much larger - and the water above it very clear.

Today I increased the speed to 60% PWM duty (from 40% previously) - but I think it's all fine, as it spins fast (and 24/7), it must be dissolving Kalk media as required.. I may add a rotary encoder to the stirrer in order to be able to adjust the stirrer speed depending on the amount of Kalk available. By weekend I will have most of Kalk being used up - and will top it off accordingly.. I can also remove the clock - initiailly I thought the stirrer would work periodically on timer, but it appears that it needs to run continously.,

Borat · Oct 31, 2021

Ok there is a significant change of direction: powering the stirrer with a computer fan is not working well. The problem is that the fan has low toqrque at low speed - the stirrer bad experiences significant resistance from Kalk especially after some time when Kalk settles..

Increasing speed makes the fan "snap" displacing the stirrer bar from central position making it spin on its axes instead..

So I need a motor that has high torque at (ultra) low speed - that's stepper motor.. I bought a 1.5A Nema 17 stepper and a TMC2209 driver for it - now working to replace the fan with the stepper motor...

Borat · Oct 31, 2021

Borat · Nov 3, 2021

Built a motor head - that allows me to flexibly change magnetic plates

Borat · Nov 5, 2021

OK the new stirrer is ready - and is working well.. relatively slow stirring, working in bursts every 30 seconds.

Borat · Nov 6, 2021

I had to change the stirrer bit - it stopped working the following morning..

Basically the magnetic field is not strong enough (there is 9mm distance between stirrer plate magnet and the stirrer bit magnet: 5mm acrylic + 3mm petri dish + 1mm clerance gap) and stirrer bit's magnets are quite weak. I doubled magnets at stirrer plate and also built this DIY stirrer ring with double magnets on each side: 6mm diameter, 6mm height, 1.6KG pull..

Finally my reactor is working well - and the tank PH is now hovering around 8.0!

Borat · Nov 7, 2021

PH is now at 8.15 - and should go higher once I implement a separate dosing line for Kalk reactor

Borat · Nov 7, 2021

The code for stirrer..

I changed it somewhat since (not in the version attached) - it now works in bursts, i.e. non-continously. Every 120 seconds it works for 15 seconds and then waits..

Average energy usage is now about 3w.

Borat · Nov 9, 2021

I came up with an even better stirrer bit design (not yet done it - but will do it next time I open the reactor lid) - I will use the existing ring piece to slope clock-wise fins while leaving counter-clockwise sides unsloped (as they are on the picture above). Because the stepper motor can be made to rotate clock-wise or counter-clockwise, the stirring process would work as follows:
- every 2 minutes it's normal stirring, moving the bit counter-clockwise (non-sloped side of protruding fins are stirring), the slurry would remain suspended in the bottom 20cm of reactor body
- every [20] minutes it's major stirring, moving clock-wise. The slurry will shoot upwards inside Kalc reactor as the sloped sides will act as propeller...

Almost certain this will work brilliantly - I will post pictures/videos in due coarse (probably tomorrow). This modification should only take about 5min to complete.. In the meantime - the existing stirrer bit works flawlessly and it's 100% silent!