Say you could slowly dose dry calcium hydroxide (kalk) in a reef tank water mixing chamber.....

[Lousybreed]

Ok, software is where I can speak. Be VERY VERY careful with feedback loops. Maybe a second PH probe is in order. If one piece of what you doing screws up ... and it will. You want to have some sort of precautions built in to deal with it. Redundancy is key here.

PH is a good pinch point to ensure levels don't get out of hand. I think that what you are going to find is that you will not be using as much of slurry as you think you will. It doesn't take very much to make things happen.

Also just as an aside. I am not sure what got on you on this contraption, but there are cleaner ways to deal with this. Please don't think that this is me saying don't do what you are doing. I ABSOLUTELY think you should, because the learning is worth way more than just buying something and using it without really understanding it. The way that I deal with Kalk is with a Kalk stirrer and a doser. I use my other method as filler for what the Kalk can't keep up with. Just a thought.

I think you are on to it. Keep posting it will be a fun ride for sure.

This actually came about because my Avast kalk stirrer is maxed out, meaning my evaporation is now my limiting factor. If I ran my system with kalk only it would drop from an alk of 8.5 to 6.5 in about three days. I was sitting around thinking about what am I going to do for my next step. Long story short I kinda just thought F-it and turned off my calcium reactor and dosed kalk slurry for a whole day. I hit 8.3 ph for the first time in a long time. Also my nightly low was over 8!!!!

As for the pH probe I hear you. I have double control on this as I have an alkatronic so if my alk were to go above my set point I would be notified and I could turn off my kalk slurry system. I am actually looking into using my alkatronic to dose the kalk slurry. It has a feedback loop that is very conservative but people are holding their alk very constant with it.

as you can see I am going to have fun with this one!!!

 

[Chuk]

If you actually wanted to try to dose dry powder you could use an auger like what’s used to feed a pellet grill. You would need to change out the motor for a servo or stepper motor to be accurate and controllable. You would also want to use a Teflon sleeve or the like and make the clearances as close to 0 as you can again for accuracy. Your biggest problem would actually be clumping due to humidity (I have had this problem before in industrial applications and we collapsed a silo when a lime bridge collapsed - I’m also a chemE).
For high volume uses we actual use slaked lime slurry. I’ve always been intrigued about designing my own slaking system at home (they’re pretty dumb basically just a temp feedback loop and a mixer) but I’ve never had enough kalk use to justify the fun.

 

[Lousybreed]

If you actually wanted to try to dose dry powder you could use an auger like what’s used to feed a pellet grill. You would need to change out the motor for a servo or stepper motor to be accurate and controllable. You would also want to use a Teflon sleeve or the like and make the clearances as close to 0 as you can again for accuracy. Your biggest problem would actually be clumping due to humidity (I have had this problem before in industrial applications and we collapsed a silo when a lime bridge collapsed - I’m also a chemE).
For high volume uses we actual use slaked lime slurry. I’ve always been intrigued about designing my own slaking system at home (they’re pretty dumb basically just a temp feedback loop and a mixer) but I’ve never had enough kalk use to justify the fun.

You are dead on for the feeding system. It could be done. But that job is not for me (never enough time) From what I am reading you will need a vibration system to stop the bridging. Too much work for me!!!!

Now on to the slurry system. I am sold this will be easier than I thought. This stuff stays suspended quite easily. I am now torn between keeping it suspended via internal pump (I think I will see massive wear and tear on the pumps ceramic bearings) or some lab scale agitator. I think in the long run the agitator is the way to go. The other way to go would be a stir plate driven mixer.

4mm tubing is pretty narrow and at 5ml/min it should have enough velocity to keep it suspended for a short distance.

 

[HuduVudu]

If you actually wanted to try to dose dry powder you could use an auger like what’s used to feed a pellet grill. You would need to change out the motor for a servo or stepper motor to be accurate and controllable. You would also want to use a Teflon sleeve or the like and make the clearances as close to 0 as you can again for accuracy. Your biggest problem would actually be clumping due to humidity (I have had this problem before in industrial applications and we collapsed a silo when a lime bridge collapsed - I’m also a chemE).
For high volume uses we actual use slaked lime slurry. I’ve always been intrigued about designing my own slaking system at home (they’re pretty dumb basically just a temp feedback loop and a mixer) but I’ve never had enough kalk use to justify the fun.

Ok this is interesting. Thank you.

 

[HuduVudu]

You are dead on for the feeding system. It could be done. But that job is not for me (never enough time) From what I am reading you will need a vibration system to stop the bridging. Too much work for me!!!!

Now on to the slurry system. I am sold this will be easier than I thought. This stuff stays suspended quite easily. I am now torn between keeping it suspended via internal pump (I think I will see massive wear and tear on the pumps ceramic bearings) or some lab scale agitator. I think in the long run the agitator is the way to go. The other way to go would be a stir plate driven mixer.

4mm tubing is pretty narrow and at 5ml/min it should have enough velocity to keep it suspended for a short distance.

You can use a magnetic stirrer. These are nice because they can be fed into your control system. I have one on my GHL and use it for stirring my CaOH concoction.

 

[Randy Holmes-Farley]

Ok please hear me out. Let’s just say you found this amazingly precise dry powder metering gizmo where you could fill a small hopper with dry kalk (aka calcium hydroxide) and it would meter the powder into a mixing chamber that contained your reef tank water. @Randy Holmes-Farley I know you mentioned if you dumped it in too fast it would cause precipitation of mag and whatnot due to the massive spike in pH. If you assume you have a slow addition all day long and your flow rate in your mixer was 500gph.....is this something that could possibly work?

Possibly? Yes. Not sure why it is necessary or useful, but yes, it could work. Some folks have dosed a slurry. Very high turbulence where it is added will be needed to offset precipitation onto or around the calcium hydroxide particles.

But if you just want a high pH alternative, you can do equally well using a DIY that uses sodium hydroxide as the alkalinity supplement.

 

[Chuk]

You are dead on for the feeding system. It could be done. But that job is not for me (never enough time) From what I am reading you will need a vibration system to stop the bridging. Too much work for me!!!!

Now on to the slurry system. I am sold this will be easier than I thought. This stuff stays suspended quite easily. I am now torn between keeping it suspended via internal pump (I think I will see massive wear and tear on the pumps ceramic bearings) or some lab scale agitator. I think in the long run the agitator is the way to go. The other way to go would be a stir plate driven mixer.

4mm tubing is pretty narrow and at 5ml/min it should have enough velocity to keep it suspended for a short distance.

My only concerns with dosing slurry would be what you say you’ve addressed with the turbulent addition location and then plugging in the dosing lines.
From my experience too high of a velocity will actually cause separation and lead to lines blocking quicker so you want high velocities to keep everything stirred up but not too high. Keep an eye at as time goes on to make sure the settling in the lines doesn’t shoot the velocities up and mess you up. Second on that front is the down time between doses. If the lines sit stagnant too long the solids will settle and begin to plug. I would recommend a designing a clean out loop and that you flush the lines with RO water every few weeks to a month. Alternatively, you could keep a spare dosing line cut and ready to swap out every few weeks. Then clean it out with vinegar or citric acid and wait for the next swap.
Good luck.
For what it’s worth I have heard of people doing what Randy suggests and use caustic for alk addition so that the kalk dosage doesn’t surpass their ability to maintain salinity.

 

[Randy Holmes-Farley]

I'll note again I can't see a reason to prefer the method to more recently developed methods, but Anthony Calfo was a big proponent of dosing calcium hydroxide as a slurry back in 2003, and this web site has a lot of discussion about it:

KalkH20FAQ2

 

[blasterman]

When you mix kalk you get an unusable sediment at the bottom of the container. If you mix the kalk in your tank then that sediment would stay in your tank which wouldn't be ideal imo

This is not true .

The precipitate that forms at the bottom of the container is calcium carbonate - the main building block of pretty much everything in your tank. It is not poison.

When I've dosed kalk for calcium / alk supplimentation I add it to a container of tank water like a juice jug, shake it, and add it to the tank. It turns cloudy temporarily and then slowly clears. There is nothing remaining. No residue - nothing. Polyps on acropora don't react.

Big coral farms I've seen in Florida that use calcium hydroxide also use the full amount. Why waste it.

By omitting the white residue you remove a major component of calcium from the formula. However, most experienced SPS keepers use kalk for top off and want the pH boost. They don't care about the calcium and alk component because they use other dosing methods.

The reason I don't keep using calcium hydroxide is I don't have a pH problem and I use enough calcium and alk on my SPS tank that I hit a precipitation wall first. I also use covered tank so I don't need an ATO and hence don't use more fresh water for tank top offs than a village in Africa.

I've also used the slurry method, but simply hit the precipitation wall.

 

[xxkenny90xx]

This is not true .

The precipitate that forms at the bottom of the container is calcium carbonate - the main building block of pretty much everything in your tank. It is not poison.

Perhaps unusable wasn't the right word. But it is the impurities I was referring to. And nobody called it poison.

From the linked article from RHF

"A drawback is the delivery of impurities in or on the solid particles, and the possibility that some solids may interact with organisms before they dissolve".

But like I said, there is minimal risk in this, especially with the ops planned method of introduction

 

[Lousybreed]

I'll note again I can't see a reason to prefer the method to more recently developed methods, but Anthony Calfo was a big proponent of dosing calcium hydroxide as a slurry back in 2003, and this web site has a lot of discussion about it:

KalkH20FAQ2

Randy I have been running my kalk reactor 24/7 and turned down my calcium reactor and I cannot keep up with alk consumption. I turned off my ATO and at the end of the day I only needed to add 1 gallon of RODI to get the sump back to my normal operating level. And this is during winter In Wisconsin, my evap rates are only going to go down from here. This is the only reason why I am thinking about dosing a slurry of kalk. I am open to other ideas!!!!

 

[Lousybreed]

Also I should say one of my goals is to get rid of my calcium reactor. Compared to kalk it’s expensive, I don’t think things like Reborn are going to be around in 5 years, and I can get Mississippi Lime food grade calcium hydroxide for like $0.60/pound. I am already making my own trace element mix so I can adjust my mix to compensate for the things that the calcium reactor produced (strontium, etc).

 

[Randy Holmes-Farley]

Also I should say one of my goals is to get rid of my calcium reactor. Compared to kalk it’s expensive, I don’t think things like Reborn are going to be around in 5 years, and I can get Mississippi Lime food grade calcium hydroxide for like $0.60/pound. I am already making my own trace element mix so I can adjust my mix to compensate for the things that the calcium reactor produced (strontium, etc).

There's nothing wrong with limewater (kalkwasser). I used it for 20 years.

But if it is not meeting demand, one can get all of the same ph advantages, and essentially unlimited capacity to add alkalinity using a DIY two part using sodium hydroxide for the alkalinity part. There are several recipes around:

Second New DIY Two Part Recipe with Higher pH Boost

In a previous thread, I posted a true two part DIY recipe: https://www.reef2reef.com/threads/new-diy-two-part-recipes-with-higher-ph-boost.344500/ But some folks may want to just swap the new ingredient into my 2/3 part recipe (as used by BRS, for example). Here's the original recipe link...

www.reef2reef.com

New DIY Two Part Recipes with Higher pH Boost

Here's a first crack at what may end up being multiple possible recipes for a DIY two part that either has a higher pH or can be made more concentrated than traditional two part recipes. This one has about twice the pH raising effect compared to a carbonate based two part, per unit of...

www.reef2reef.com

Instead of making them more complicated with extra ingredients beyond NaOH and CaCL2,, one can use the stripped down version with Balling Part C for ionic completeness.

 

[Lousybreed]

There's nothing wrong with limewater (kalkwasser). I used it for 20 years.

But if it is not meeting demand, one can get all of the same ph advantages, and essentially unlimited capacity to add alkalinity using a DIY two part using sodium hydroxide for the alkalinity part. There are several recipes around:

Second New DIY Two Part Recipe with Higher pH Boost

In a previous thread, I posted a true two part DIY recipe: https://www.reef2reef.com/threads/new-diy-two-part-recipes-with-higher-ph-boost.344500/ But some folks may want to just swap the new ingredient into my 2/3 part recipe (as used by BRS, for example). Here's the original recipe link...

www.reef2reef.com

New DIY Two Part Recipes with Higher pH Boost

Here's a first crack at what may end up being multiple possible recipes for a DIY two part that either has a higher pH or can be made more concentrated than traditional two part recipes. This one has about twice the pH raising effect compared to a carbonate based two part, per unit of...

www.reef2reef.com

Instead of making them more complicated with extra ingredients beyond NaOH and CaCL2,, one can use the stripped down version with Balling Part C for ionic completeness.

Good info!!! Thank you for the ideas.

 

[Lousybreed]

Quick update. You can check the details out on Instagram (Mahina Corals) where I have posed my kalk slurry journey. Long story short it works amazingly. I have turned off my calcium reactor (I call them carbonic acid generators now). My daily average pH is through the roof (8.4 in my system for an average). I went with the liquid slurry dosing method.

 

[Dan_P]

Quick update. You can check the details out on Instagram (Mahina Corals) where I have posed my kalk slurry journey. Long story short it works amazingly. I have turned off my calcium reactor (I call them carbonic acid generators now). My daily average pH is through the roof (8.4 in my system for an average). I went with the liquid slurry dosing method.

This sounds like a good topic for an article on R2R.

 

[Lousybreed]

This sounds like a good topic for an article on R2R.

How do I go about doing this?

 

[Dan_P]

How do I go about doing this?

@taricha @Rick Mathew would you provide some guidance about article writing?

 

[User]

Been following you IG in this for a couple weeks and it looks like you have it dialed in. Thanks for continuing to share here, despite the initial resistance to giving due appreciation to your professional roots. I think people get too stuck into the whole “we tried that 10 years ago and it was a bust” without appreciating that understanding and techniques have changed.

anyway- I’m very interested in trying this and bypassing getting a CaRx. I currently have a 250g system, but will be upgrading to around 400g in a year.

Any comments on safeguards? One of your IG stories suggested you only feel comfortable testing this because you have auto alk monitoring and this gives you a real time assessment and ability to turn things off if they get ugly.

since alk measurements are pH titration based- could I use pH as an indicator and rig up my apex to shut off the dosing if my pH goes uncharacteristically high or low?

my pH is pretty good- 8.38/ day, 8.52/night. Once dialed in, do you think pH monitoring would work, or would you only recommend doing this if you have auto alk testing?

also- how long before you consider a 5gallon magnetic stir plate or an external overhead stirrer? That slurry is going to do a number on regular pumps

thanks for continuing to share your work- very much appreciated

 

[Cory]

Randy has a publication even stating this is an acceptable method of using alk as long as you don’t raise the pH too fast.

You could use a ph probe in your sump and a doser that doses the slurry based on ph with an apex. Just have the apex stop dosing the slurry if the ph gets to 9.5 and when it drops to an acceptable level, continue dosing. I would love to see what youve done with your slurry in that bucket!