View Full Version : Kalk Dosing Questions

07/24/2010, 08:42 AM
So, I'm a complete noob at Kalk dosing and need a little bit of help. I have been dosing a 2 part solution in the past but have recently decided to start dosing kalk to make it a bit more hands-off. At the advice of my lfs, I have mixed the kalk in my top-off resevoir (10 gallon), and is fed to the sump w/ an aqualifter/float-valve auto-topoff for the evaporated water. I also placed a small powerhead in the resevoir on a timer that runs for 15 minutes every 6 hours to make sure the kalk doesn't get nasty on the bottom. My questions are:

1) Is this a good way to dose kalk?

2) Do I still need to dose the 2 part solution?

3) Do I need to dose the 2 part solution after a waterchange for a few days?

Thanks! :beer:

07/24/2010, 08:50 AM
You don't want to mix the kalk water after you do the initial stirring to get it dissolve. Mixing afterwards will add more CO2 into the water and will lead to more calcium carbonate precipitation. This will make the kalk water less potent. Also you don't want to dose the nasty stuff at the bottom, so you want it to settle on the bottom. The nasty stuff contains contaminates like heavy metals (copper) you don't want in your tank. Your draw tube should be a couple inches off the bottom of your kalk tank to prevent dosing the precipitants. :)

A float switch only may allow too much kalk to be dosed at one time. It is best to use a dosing pump with a timer. This will also help prevent kalk overdoses that will raise your pH too high if the float switch sticks. This leads to snow storms, which you don't want.

Usually when you first start dosing kalk water, you mix around 1 teaspoon of kalk per 1 gallon of rodi water. If this doesn't meet alk demand, then you will need to increase the amount of kalk per gallon. After you reach 2 teaspoons of kalk per gallon, you will not be able to dissolve any more kalk per gallon. At that point you may need to dose a two-part as well.

07/24/2010, 08:52 AM
I recently added kalk to my tank as well to help combat a low ph issue I was having. IMO you need to use a more accurate way of dispensing enough kalk to keep up with your demand. I have a Litermeter dosing pump I use to drive my kalk reactor. That way I know exactly how much is going in my tank daily so I can keep my alk/ca stable.

Kalk supplements may work and maybe not. The reason for this is you can only add enough kalk top-off water to your tank maxing at the point where you are replacing all evaporated water by kalk. Thats it. Ya know what I mean? Might be fine depending on how much coral you have in your tank that consumes alk/ca..

07/24/2010, 08:55 AM
For more details see Randy's article:

What Your Grandmother Never Told You About Lime

07/24/2010, 09:17 AM
I've been dosing it for years from a still reservoir. As Cliff notes don't stir it after the intitial stirring ;let it settle for at least a couple of hours , then dose the clear kalk water and don't dose the slurry on the bottom ,it is full of undissolved kalk and precipitated impurites. Once you mix it in the freshwater, the kalk will hold it's stength for weeks in a loosely coverd container( like a garbage can) Dosing cloudy water can and often does lead to an overdose. You an just stir it in manually. I use a piece of pvc pipe and swirl it around in the container for 20 of 30 seconds until a vortex forms. The powerhead will probably be cvered in calcium carbonate after a short period of time so I wouldn't use it in this application.

It is important to spread out the dose over the longest period of time possible. Ideally 24/7 , imo. The liter meter is good for this since it breaks down any amount you set it to dose into 150 equal increments spread over a 24 hour period. It is pricey and less precise alternatives work well for many.

07/24/2010, 11:08 AM
The tank is a mixed reef with NO sps, just typical softies and lps. The reason I decided to start dosing kalk was just to simplify things so I didn't have to worry about manually dosing the 2 part solution every day. I understand that there are always many different methods and ways of doing things, I'm just looking for the easiest (hands off) way to dose the tank that will work for my setup. So it sounds like the first thing I need to do is take out the powerhead from the topoff resevoir. Next, raise the tube off the aqualifter a couple of inches off the bottom of the resevoir so it doesn't suck up the nasties into the sump. The resevoir itself just has a quick connect drilled into the lid so I can just plug in the rodi and fill 'er up when it gets low. Is it going to be a problem over time with that nasty water sitting at the bottom?

Cliff - I want to make sure I am following you correctly: After I start dosing, keep testing the water to make sure parameters are met. If they are with the Kalk+2, I don't need to dose the 2 part, right? Only after kalk dosing is increased (and maxed out) at 2 tsp per gallon, and needs are NOT being met do I start supplementing with the two part again?


07/24/2010, 12:51 PM
You will need to occationally clean out the precipitation in the bottom, which it rises closer to your intake tube. Some only clean it once or twice per year depending on your container.

Yes, you are correct. You will want to dose your kalk water to maintain yoru alk level & the calcium level will automatically follow suite. If your alk level is not met and drops, then increase your alk level using calcium chloride (two-part) and then increase your kalk mix a bit. If your alk level goes to high, then stop dosing kalk water until your alk drops & then resume dosing your kalk water with less kalk in it. It may take some playing around with your mix to get it right. :)

07/24/2010, 01:56 PM
HighlandReefer is on it... Good advice.

07/24/2010, 02:18 PM
I clean my kalk reservoir out every 3 months or so but it really doesn't matter as long as you let it settle out after mixing before dosing it.

FYI kalk is calcium hydroxide.The calcium and alkalinity provided by kalk dosing is balanced. The hydroxide joins CO2 in the water and forms carbonate which is alkalinity. This interaction reduces CO2 and increases ph. If too much is dosed at one time the ph will spike and calcium carbonate will precipitae out of solution . The ph of fully saturated limewater is about 12.4 . Generally,depending on the alkalinity level, it will precipitate out of the water in the tank with ph much over 8.5 dkh.

07/24/2010, 02:33 PM
Thank you all very much for the help!! I unplugged and removed the powerhead, raised the intake tube, and am going to test tommorrow to see where my levels are... I'll be sure to post here all the readings as I appreciate the much-needed help and advice...

07/24/2010, 04:13 PM
Ok, so this has been somewhat of a boring Saturday so I decided to go ahead and take some readings. Things are looking a bit off so I'm definitely in need of some help adjusting to the right levels...

Tank Details:
~140 gallons (7ftx18"x12" display w/ 55 gallon sump filled up about 2/3 of the way)
~160 lbs. live rock
4 X 54W T5 (spectrum and actinic 9 hrs daily)
HD clip-on light w/ plant bulb for fuge (opposite display lights)
ASM G2 skimmer
mag 9.5 return
koralia 5,3,1
basketball sized cheato
32 mangrove plants
10 gallon top-off resevoir (fed from aqualifter using a float valve) (**dosing kalk here**)

as of about 10 min. ago:
Calcium - 410
KH - 10.9 dKH
Alk - 3.89meq/L
PH - 7.8

Alk looks high and ph low..... :( What is causing this?

note: I'm mixing water as we speak for my biweekly water change tommorrow, so I'll take readings again late tommorrow to see what happened. I thought it might have something to do with Co2, so I aimed a koralia at the surface for the time being...


07/24/2010, 04:14 PM
The Kalk+2 doesn't work the way it's advertised. The magnesium will precipitate to the bottom. As far as the strontium, there's no real need to dose it:


I'd use up what you have, and switch to a better product, personally.

07/24/2010, 08:03 PM
I didn't catch the K+2 reference. I agree it is a poorly designed product.The magnesium will never get into your water in soluble form.

The low ph could be from excess CO2 due to decay in the tank, poor gas exchange with the air as in a closed up tank or one without skimming or surface agitiation or high CO2 in the air around the tank. However, ph would usually be higher than 7.8 with kalk dosing since kalk is high in ph and uses CO2. How much kalk are you mixing into your ro water? Have you tested the ph of the kalk water? How are you measuring ph? The alkalinity , calcium and magnesium levels will depend on your salt mix and sg as well as dosing. What else are you dosing if anything?

07/27/2010, 08:07 AM
OK - here is an update. I did a waterchange yesterday and am waiting until this evening to test the water. Sometime strange is going on though, as my skimmer cup is filling rapidly. I normally clean the cup weekly, and there is a small amount of black skimmage. This is one day after the waterchange and the skimmer cup is half-full with black/brown skim. Nothing else is being dosed other than the kalk+2, and lugol's iodide once weekly. Any ideas?

07/27/2010, 02:37 PM
The water change might have added nutrients that encourage some sort of growth. That's fairly common. Something might have died, too. If none of the animals are having trouble, I wouldn't worry, but I'd watch carefully for a day or so.

07/27/2010, 05:12 PM
Ok and thank you bertoni - I checked all of the fish & inverts are "present" (lol) and all look healthly and happy. I emptied and cleaned the skimmer cup again this morning and have been keeping an eye on it today to see if it is still filling quickly, and it appears to have slowed down a bit. I just tested and here are the parameters the next day after water change:

Calc - 390 (lowered, so Im guessing I'm going to have to dose calcium on the 1st day after each water change since the only tank nutrients are now coming from the top off resevoir.

KH - 10.9
Alk - 3.89
Ph - 7.8 (this is stubborn and annoying)

To answer someone's previous question, I am using salifert test kits for the above parameters, then the api stuff for nitrate & phosphate.

Also, I use instant ocean salt & a 4 stage ro/di that is getting close to change-filter time as the tds meter is steadily increasing.

The K3 pointed right at the surface doesn't seem to be helping the ph issue - I was hoping it would if it were a Co2 problem. Any other thoughts or ideas?

One more question too - since I pulled the the aqualifter intake an inch off the bottom of the topoff resevoir, there will always be an inch of kalk water in the bottom. Is this going to be a problem? 1 inch is almost exactly 1 gallon of water, and the plastic bin holds 10. I rigged a quick connect fitting into the lid so I can just plug in the ro/di to add water back in the resevior, so basically there will always be a gallon of water sitting on the bottom mixed with kalk. I guess I would then only add tsps of Kalk back to the 9 gallons I refill?


07/27/2010, 05:18 PM
You can keep adding to your bottom 2" and add the appropriate amount of kalk per gallon without harm. Let the kalk reservoir settle before you start dosing again. :)

07/27/2010, 05:44 PM
You can keep adding to your bottom 2" and add the appropriate amount of kalk per gallon without harm. Let the kalk reservoir settle before you start dosing again. :)

Thank you Cliff!! :beer:

07/27/2010, 09:27 PM
The pH problem probably is caused by a high level of carbon dioxide inside the house. If that's the case, more aeration won't help.

07/27/2010, 09:47 PM
The pH problem probably is caused by a high level of carbon dioxide inside the house. If that's the case, more aeration won't help.

I guess my wife and I need to quit breathing so much :lolspin: Once it cools off here in (prob December), we leave the windows open and hopefully that will help. Should I do anything in the meantime or just get over it and let it ride at 7.8?

07/27/2010, 10:56 PM
I would let it ride. :) Or stop breathing. :lol:

07/28/2010, 01:28 PM
I would let it ride. :) Or stop breathing. :lol:

Sounds good and thank you again Jonathan, Cliff, and everybody else! :dance:

07/28/2010, 08:08 PM
Your welcome.

Happy Reefing. :)