Maintaining kalk reactor/stirrer

[jcjrogers]

I'm interested in adding kalk with ATO. When I've done this in the past, I added kalk directly to the ATO tank (a salt bucket). I like the concept of keeping RO/DI in the ATO tank and running that through a kalk reactor/stirrer. This would make it easier on the pump, and allows for taking the reactor/stirrer offline without shutting down the ATO for more than a few minutes.

I also would like a kalk system that can run hands-off for 3 or 4 days but don't know if this is possible with this type of setup. Furthermore, I don't understand the process of maintaining a reactor/stirrer. In other words, what is the process for adding more kalk powder? How do I know when I need to add more kalk powder? Would I have to disconnect and clean the reactor/stirrer every time I add more kalk powder?

 

[ReefTeacher]

I have the AVAST kalk stirrer and love it. The directions say add kalk 2x a week, I just dump it in. I clean it out about once a month and twice a year I give a quick vinegar rinse. It is easy and cheap!

 

[jcjrogers]

Where I'm confused is, let's say the stirrer holds 2 quarts and I'm topping-off around 2 gallons per day. I put 2 tablespoons of kalk powder in the stirrer. That's good for a gallon of top-off but I'm not going to try to keep up with the fact that a gallon of water has left the top-off tank.

I guess I'm assuming that since only so much calcium hydroxide can be kept in solution, you could put in say 16 tablespoons, which would be good for around 8 gallons of top-off water. Since the stirrer concentrates a little better, maybe that's 2.5 tablespoons per gallon of top-of water. Is this the way it works?

 

[ReefTeacher]

You should adjust based on your calcium demand. I add about 1/3 C of Kalk once per week, but some add up to twice that amount. The stirred keeps it saturated so you don't have to add the powder so frequently. AVAST has a table on their website showing how much top off you add and the corresponding about for a saturated Kalk solution. I go below saturation for my needs. You have to experiment a little.

 

[jcjrogers]

You should adjust based on your calcium demand. I add about 1/3 C of Kalk once per week, but some add up to twice that amount. The stirred keeps it saturated so you don't have to add the powder so frequently. AVAST has a table on their website showing how much top off you add and the corresponding about for a saturated Kalk solution. I go below saturation for my needs. You have to experiment a little.

This is one of the things I'm not understanding... if adding less than or equal to saturation, how do you keep from losing it all very quickly? For instance, if the stirrer holds a quart of water and 1/2 tablespoon of kalk powder is used, which completely saturates that 1 quart, wouldn't you lose 100% of your lime water with the next quart of top-off?

 

[Celtic_Fox]

This is one of the things I'm not understanding... if adding less than or equal to saturation, how do you keep from losing it all very quickly? For instance, if the stirrer holds a quart of water and 1/2 tablespoon of kalk powder is used, which completely saturates that 1 quart, wouldn't you lose 100% of your lime water with the next quart of top-off?

I think the whole point of having a stirrer is to put in much more than the saturation amount. When some of the saturated solution is used and freshwater is added, the stirrer stirs up the precipitate at the bottom bring the solution up to saturation point again.

 

[Celtic_Fox]

Oops, forgot to add: And that any Kalk you add weekly or so is to stay ahead of use and keep a good amount of precipitation on the bottom, for the next week or so's use.

 

[jcjrogers]

Ok, I'm a little thick, but I think I understand. Simply, with a stirrer, you are always adding the maximum saturated solution, which is fine by me (hard to justify getting a stirrer if you aren't doing that). Since my goal is to manage pH and to use as little 2-part as possible, I want as strong of solution as I can get and want the luxury of having to mess with it as infrequently as possible.

 

[ReefTeacher]

And many people make sure they are at the saturation point. But some of us find our calcium demand lower than that, and we don't want the alkalinity constantly creeping up, so we make adjustments.

 

[ReefTeacher]

This is one of the things I'm not understanding... if adding less than or equal to saturation, how do you keep from losing it all very quickly? For instance, if the stirrer holds a quart of water and 1/2 tablespoon of kalk powder is used, which completely saturates that 1 quart, wouldn't you lose 100% of your lime water with the next quart of top-off?

This is true if equilibrium is reached quickly. But in practice, the saturation of Kalk takes a long time, it is kinetically limited, not limited by the amount of Kalk available. So you often end up added a less than saturated solution.

Of course, there are also people who dose a "milky" Kalkwasser, that is adding more Ca(OH)2 than would be possible in a clear solution. So many adjustments are possible, it turns out to be more flexible than you might first think.

 

[FirstContact]

I think the whole point of having a stirrer is to put in much more than the saturation amount. When some of the saturated solution is used and freshwater is added, the stirrer stirs up the precipitate at the bottom bring the solution up to saturation point again.

Yup. That's how it works. I have a medium MRC Kalk reactor that I got years ago from Aquarium Specialty. I use it with my Tunze Osmolator and my controller which used to be an Apex classic but is now a Vertex Cerebra.

I typically dump in a single pound bag of Mrs Wages pickling lime and let the reactor run off of that until there is very little left and then I add another one pound bag. The water in the reactor is always saturated. The top off adds new water to the bottom of the reactor which pushes saturated water out into the sump. It works off a pump instead of a stirrer, and I typically clean it once or twice a year even though that seems to be overkill. I find that if I use Kalk from a sealed container (like the one pound single use bags rather than reopening a jar or bucket of Kalk) the reactor and pumps never really get dirty with Kalk sticking to them.

You use the controller to mix the Kalk every few hours and to shut off the auto top off if the pH ever gets too high.

 

[Logzor]

I just bought the Avast Kalk Stirrer and will have it hooked to my Apex. Maybe I'll only run the stirrer at night so have the most advantageous use of the pH boost? It might just get fully saturated anyhow day and night even with the intermittent stirring...

 

[Walla2GSP]

And many people make sure they are at the saturation point. But some of us find our calcium demand lower than that, and we don't want the alkalinity constantly creeping up, so we make adjustments.

Not meaning to highjack the thread, but if your needs are less than saturated wouldn't it be more effective to run two ATO pumps on timers and set the kalk stirrer to run at night and the RO res to run during the day light hours? I would think your kalk would be too diluted after the first day to make an effective change in pH if it's not maintained super-saturated.

 

[FLSharkvictim]

Avast kalk question

Avast kalk question

I have the AVAST kalk stirrer and love it. The directions say add kalk 2x a week, I just dump it in. I clean it out about once a month and twice a year I give a quick vinegar rinse. It is easy and cheap!

What model did you buy from Avast? Also, can you hook it up to your Apex controller?

 

[ca1ore]

I have the smaller avast unit, and plug it into the EB8. I run it periodically, but not continuously. I do run dual ATO pumps, one through the avast and one not. Apex picks which based on tank pH.

 

[jcjrogers]

I have the smaller avast unit, and plug it into the EB8. I run it periodically, but not continuously. I do run dual ATO pumps, one through the avast and one not. Apex picks which based on tank pH.

This is my plan. However, in my past experience with kalk, I never saw pH get as high as 8.4 though I wasn't using a controller only random testing. Therefore, I thought I might start with just the one pump, shutting it down and sending an alarm if pH over maybe 8.4 to see if the backup pump is really necessary. What do you have your pH trigger set at and how often do you exceed that (e.g. how often does the Apex engage the bypass pump)?

 

[ca1ore]

This is my plan. However, in my past experience with kalk, I never saw pH get as high as 8.4 though I wasn't using a controller only random testing. Therefore, I thought I might start with just the one pump, shutting it down and sending an alarm if pH over maybe 8.4 to see if the backup pump is really necessary. What do you have your pH trigger set at and how often do you exceed that (e.g. how often does the Apex engage the bypass pump)?

I have my trigger set to 8.3; though my tank rarely gets over 8.2 and never to 8.3 so it's somewhat academic. I use the second ATO pump as a failure backup primarily, so float switches would trigger it as well as pH. Plus I use the Apex OSC command to cycle it daily so it will work when I need it to work