Controller to dose kalk?

[Scottsquatch]

I have been thinking about reliable ways to dose kalk to maintain Ph, alkalinity, and calcium. I was wondering if anybody ever tried connecting a small lift pump to a stirrer to dose kalk via a controller. I was thinking I could place the pump in the ATO reservoir and have it leading to a kalk stirrer and then into the sump. Set the controller to activate this pump whenever Ph falls below the desired level. It would add limewater to the sump very slowly until it reaches the desired level. It seems this would be much more acurate than relying on evaporation (which fluctuates drastically by season here) to dose kalk. I am questioning if using ph to controll the dosing would provide enough alkalinity and calcium to keep up with coral demand. Furthermore, is this a stupid idea? Would a calcium reactor be a better way to go? Any insight would be very much appreciated.

 

[Brew12]

I have been thinking about reliable ways to dose kalk to maintain Ph, alkalinity, and calcium. I was wondering if anybody ever tried connecting a small lift pump to a stirrer to dose kalk via a controller. I was thinking I could place the pump in the ATO reservoir and have it leading to a kalk stirrer and then into the sump. Set the controller to activate this pump whenever Ph falls below the desired level. It would add limewater to the sump very slowly until it reaches the desired level. It seems this would be much more acurate than relying on evaporation (which fluctuates drastically by season here) to dose kalk. I am questioning if using ph to controll the dosing would provide enough alkalinity and calcium to keep up with coral demand. Furthermore, is this a stupid idea? Would a calcium reactor be a better way to go? Any insight would be very much appreciated.

Not crazy at all. In fact, I'm about to take a similar step in a more conventional manner. My dosing unit arrives today.

My evaporation is too inconsistant to only use kalk in my ATO. So, I am setting up a separate kalk container, no stirrer, with 2tsp/gal of water. I will have my doser add around 3/4 gallon per day of this solution, spaced throughout the day. My normal ATO will make up for the rest of the evaporation. I will set a high pH shutoff to be on the safe side.

When this isn't enough to make up the Alk/Calc demand I will add 2 part dosing to it.

If you have very high demand, a calcium reactor is probably the best way to go.

 

[Randy Holmes-Farley Verified Community Expert]

I think the issue is likely to be that controlling via pH is a potential problem in that it takes no account of whether alkalinity is low or normal or getting too high.

If evaporation is too variable for your alk stability desires, I'd just put the limewater on a timer and dosing pump, the pH control only to stop if it the pH got too high (say, above 8.55) as an emergency stop.

 

[Scottsquatch]

No, this will be on a new system. I dont even have it wet yet. Thats why I was thinkin kalk would suffice for now. The reason I was thinking of using a stirrer is to esure the limewater saturation would always be high. Is the stirrer probably unnecessary?

 

[Scottsquatch]

I think the issue is likely to be that controlling via pH is a potential problem in that it takes no account of whether alkalinity is low or normal or getting too high.

If evaporation is too variable for your alk stability desires, I'd just put the limewater on a timer and dosing pump, the pH control only to stop if it the pH got too high (say, above 8.55) as an emergency stop.

Yeah, I didnt even consider that. Im new to this part of reefing as all water chemistry needs in my past tanks were met with water changes. Nanos are easy that way.

 

[Scottsquatch]

Dumb question Randy. Dont alkalinity and Ph usually kinda go hand in hand or am I way off base here?

 

[Randy Holmes-Farley Verified Community Expert]

No, this will be on a new system. I dont even have it wet yet. Thats why I was thinkin kalk would suffice for now. The reason I was thinking of using a stirrer is to esure the limewater saturation would always be high. Is the stirrer probably unnecessary?

I don't prefer for stirrers and folks often find them less than saturated, while a settled reservoir can be saturated or less than, depending on what you add.

 

[Randy Holmes-Farley Verified Community Expert]

Dumb question Randy. Dont alkalinity and Ph usually kinda go hand in hand or am I way off base here?

Not really, no. pH is determined mathematically by the carbonate alkalinity and the CO2 level in the water.

Limewater tends to reduce the CO2 level, so it can help raise pH, while other ways of adding alkalinity tend to have a smaller effect (carbonate addition) or even cause a decline (CaCO3/Co2 reactors and bicarbonate dosing).

 

[italquam]

I don't prefer for stirrers and folks often find them less than saturated, while a settled reservoir can be saturated or less than, depending on what you add.

Randy if not a stirrer, what is the best way you consider dosing Kalk......?

Through a ATO, or by dosing pump, or some other methods??

 

[Scottsquatch]

Up above he recommended a doser.

 

[Randy Holmes-Farley Verified Community Expert]

An ideal system, IMO, is limewater from a settler reservoir using a dosing pump set to a speed just under the daily evaporation limit.

For 20 years I used it in a slow pump ATO and was happy with it, but the limewater dose was likely variable and some folks think alk stability is important. I’m not sure if that is generally true for a non SPS tank, but it might be.

 

[Cary Hover]

I use a calcium reactor in my 450. Keeps levels perfect and I don't have to dose. Takes a little patience to learn your reactor and how to adjust CO2

 

[Scottsquatch]

For my 220, I'll definately go that route. This is a small system though and I'm not sure a calcium reactor would be feasable. Do they even make them for small systems? If so, I would probably be interested.

 

[NaH20nerd]

For what it’s worth, I tried dosing Kalk using ATO. Albeit only for a few days. Found that my evaporation was too low to consistently add appropriate Kalkwasser.

So I decided to use a dosing pump. First I determined what Alk/KH my tank was using on avg per day. Then I used the below Kalkwasser calculator to determine how many ML to add daily. I’m on week two and after dialing the dosing pump in...it seems to be holding steady. Oddly though, my PH still never gets above 8.0...but now it never gets below 7.8 either. So I’m good with it.

Kalk calculator
https://www.hamzasreef.com/Contents/Calculators/KalkContribution.php

Dosing pump:
Horizon Aqua D100
WiFi dosing pump. Roughly $80