[Marc Smith]

Preparing Kalkwasser

The more hobbyists you listen to, the more methods you will come across about how to prepare Kalkwasser (Limewater) in the proper manner. This is unfortunate, as it is confusing for beginners especially. There really is no one and only propper manner in which to prepare Kalkwasser ideally.
All methods advocated are really not that much different from one another. Some hobbyists may use a little more calcium hydroxide and others may use a little less. The concensus, though, is that the chemical to use is calcium hydroxide (and not calcium oxide).
Do not expect to find the ideal way here either. All I am going to give you is the method that I have used for years. I have always been satisfied with the end result, and have consistently obtained KW with a pH of over 12.2, and a pH that maintained itself.

How is this done?

Using treated water, that has gone through a reverse osmosis filtration unit and then through a silicate removing compound, I add 3 level teaspoons of calcium hydroxide, per gallon of water, that I prepare.
I then very gently stir the mixture. Not forcefully, just gently, to mix to powder with the water evenly. The reason I mix it gently is to prevent (or minimize) the amount of carbon dioxide that gets into it. After I finish mixing, powder settles to the bottom of the vat. That is normal since not all powder will dissolve. Water can only absorb so much calcium hydroxide before it becomes saturated. This is a chemical fact. Note, also, that cold water absorbs more of calcium hydroxide than lukewarm water or warm water.
What should the pH be

After I have mixed the powder and the water, when I place a pH electrode in the mixture I will get a reading of over 12. This has been so each time I prepare the KW in that manner. This is encouraging as fully saturated KW has a pH of around 12.4 or thereabouts.
In any event, regardless of what you do, you must ensure that as little carbon dioxide as possible gets into the water and calcium hydroxide mixture as this would result in the formation of calcium carbonate that will settle to the bottom, and does not dissolve. This process also lowers the pH of the mixture, which is not desirable.
This is an easy method to follow.
Every time you prepare more Kalkwasser I recommend that you dispose of the excess powder in the bottom of the container. This is not a must but it is better, in my opinion, to do so.

Sorry I was bored, and wanted to post a mid Summer reef post. Hope you find it useful.

Thanks,

Mike Lopez

(Got this Article from Mike. I thought it was a good one. He posted it on another board some time ago, and gave me permission to repost. Thanks!)

~The Hermit

[Duds]

good post I may have to use limewater to top my fish tank up from now on. Just need to find a place to get some. I can use a drip feed and drip it directly into my display without any problems right?

[graveyardworm]

When dripping Kalk care should be taken to monitor ph. As Foghat pointed out the ph of kalk is very high and will raise your ph as it is added. Once you know how ph will be affected then the regular monitoring can probably be slacked off a bit. I would suggest you get an electronic ph monitor for ease of use.

[chief]

good article. i tried the kalk for a little while and thought it was a waste if you ask me. mixing some kalk with water and letting it sit overnite or however long you chose then slowly dripping it is a pain. Unless of course you have an auto-top off machine then i'm sure it's a piece of cake. I don't have that so I'd have to have that container in front of tank dripping for a day or however long i had it slowly dripping it.

I've been using Randy's Two Part Solution with dowflake and it's so much easier with less effort. I mix a gallon of calcium and alk with Randy's formula and it lasts me a month or more... Every few days I toss in 3/4 - 1 cup of each directly into sump and i'm done in 2 minutes. bing bang boom

[ReeferMedic]

Since we are making a saturated solution, you don't have to worry about adding any specific amount. Ifg you add too much, the ph isn't going to get any higher. You just have to make sure you add enough. I just add a bunch of it to my top off container every few days, and the stuff that doesn't dissolve sinks to the bottom. I know when to add more when there isn't alot settling out on the bottom.

[mfreef]

As we know at night time when the lights go out our corals produce c02 and our ph swings low..that is why I drip kalk over night and not with top offs..I believe the ph upswing from the kalk isnt as much of a concern this way! I have also heard that you do not want the solid form to enter the tank(the undissolved kalk)!

[ReeferMedic]

Originally Posted by ReeferMedic

Since we are making a saturated solution, you don't have to worry about adding any specific amount. Ifg you add too much, the ph isn't going to get any higher. You just have to make sure you add enough. I just add a bunch of it to my top off container every few days, and the stuff that doesn't dissolve sinks to the bottom. I know when to add more when there isn't alot settling out on the bottom.

Forgot to add, I only top off at night. I have a timer that starts a peristalstic pump when the lights go out, and it stops top off when they go on. I just calculated my total top off to a 16 hour period.

[Cobraz]

Originally Posted by chief

I've been using Randy's Two Part Solution with dowflake and it's so much easier with less effort. I mix a gallon of calcium and alk with Randy's formula and it lasts me a month or more... Every few days I toss in 3/4 - 1 cup of each directly into sump and i'm done in 2 minutes. bing bang boom

One thing I have read is that when adding Calcium and Alk - you can not add them at the same time it counter acts each other - they (Randy and others) suggest waiting 8 hours or alternate daily between the two.

[ReeferMedic]

I also use the kalk more to stabilize ph, not so much for the ca and kh levels. Most people that run ca reactors have to drip kalk to help counter the low ph of the reactor effluent, especially at lights out.

[rmhgold1]

I tried Kalk and it did nothing for me. I use Randy's Two Part Solution. I kept the sqiurt bottles from a ETonic A-B. I mix a gallon of calcium and a gallon of alk, following Randys. Fill up the squirt bottles, and each morning, 2 squirts alk(20 ml...10ml per 40g) and 2 squirts calcium.--I have a 75g. And once a month drip a gal of water and calcium-10/tsp, if my calcium needs to go up a bit. I only wait about 5 minutes between squirting in my alk, then my calcium.

Getting the Kalk to regulate was too much trouble...Also my PH is 8.4

Rich

[Maineiac]

and then through a silicate removing compound,

Is this referring to something different than running through an DI unit?

Thanks, Tim