Recently a member asked me about kalkwasser and I wanted to bring my response out on the forum for all to see learn from, add to, and comment on.
First off, I would try to get away from the liquid stuff and into the powders ASAP as your paying for a lot of water and not much ‘product’.
Second are you testing and sure that you need to be dosing calcium and alk? What do you have in the tank that consumes calcium?
Third (and maybe most important) what are you magnesium levels? These are necessary to keep calcium and alkalinity levels where we want them.
Now to the kalk which you asked about…
Dripping kalk is easy and if you come to the next meeting I’ll bring you a ziplock bag for you to get started with. I simply have a milk jug (clean out very well) that I punched a hole into and stuck a tube in. Make sure your tube is at least an inch off of the bottom so there is area for the carbonate/un disolved kalk, ect. to settle and you are dripping in the saturated lime water. Then take your tube and simply run into to your sump with a few knots in to reduce the drip rate to your evaporation rate, about 1 drip a second.
Saturated limewater (kalk) has a very high ph of about 12 and can only be dripped in, too much at once will spike your ph up too high. It can also be as dangerous as acid (just on the other end of the scale), so some care should be taken.
The high pH of the kalk helps to reduce acids in the water that would otherwise lower you alk, the kalk also adds a little bit of alk as well as calcium. The high pH also helps to drop phospahtes and other impurities as out the water as it will precipitate out.
I really don’t let the water set, but I know some folks let it sit over night. So say to be on the safe side 8 hours? I do get some particulate that comes through my drip line though and really only want the clear stuff. I haven’t noticed any ill effects though.
I forgot to add the mixture is about 1.5 teaspoons per gallon of RO/DI water. Make sure you are using RO/DI water in your kalk or most of the impurities will precipitate out into the bottom of your bucket.
Anyone interested in doing this should also read through these links and at least familiarize themselves with some of the chemistry involved in our tanks.
Well, Ian, you’ve unleashed a flurry of questions:
Since kalkwasser is high in ph, what would the ph impact be in dripping it into a tank where the ph has held pretty consistent? Wouldn’t I likely get ph creep?
So what do you do with the settled particulate left over after each dosing? Does it simply get remixed with the next batch, or dumped?
And how often do you mix up a batch? Could you make up a weeks worth at a time?
I also wonder whether there is any advantages/disadvantages to aerating the mix with an airstone to prevent the settling?
And lastly, isn’t the amount of the kalk added to the RODI water influenced by what your tank is using each day, based on some trial and error measures of alk and Ca levels?
Most people drip in kalk at night when your lights are off and the photosynthetic process doesn’t convert co2 into oxygen (i.e. your ph drops). You could get pH creep I suppose if it is constant (even at night), but I wonder how your pH is kept constant at night. I don’t know if I’ve experienced it, I’ve only tested pH with those stupid color charts which are worthless IMO so I don’t test it.
Anything that is settled is either undisolved kalk (you put in too much) or calcium carbonate. I make sure the tube sticks up from the bottom of the jug enough so it doesn’t suck it in. I haven’t cleaned my jug in the past few months since I’ve been dosing it.
I would suggest making up only a gallon at a time, 5 gallons max. The longer it sits out the more co2 from the atmosphere it will absorb and turn into carbonate.
I’d suggest against aerating the mix as this would cause it to function as a co2 scrubber for your basement! Again removing the co2 from the air and settling at the bottom of jug as carbonate. logans_daddy on here has a DIY on a kalkwasser stirrer.
Only so much kalk can dissolve into water. About 1.5 teaspoons per gallon of RO/DI.
If your tank is using a LOT of Ca and alk you may not be able to maintain it with just kalk and will need to look into other supplimentation. There is also spiking your kalk w/ vinegar but I personally haven’t done that yet (trying it tonight). That will allow you to put more ‘kalk’ in w/o it affecting ph as much.
ive heard the stuff you get is grade A so im guessing you dont need a lot of it???
anyway, in relation to where your other parameters are (calc, mag, alk), how do you specifically determine how much kalk to add…do you use a calculator online or have a rough feel for it? or slow drip and test?
i have a kent marine doser where the tube is at the bottom of a funnel so im not sure if there would be any settling at the bottom issues…
my nitrates are dropping like crazy now, and im getting closer to my dream of sps/lps…although i already have a few hardy species, im looking to get some other frags…
like sean recommended a while ago to me about needing to be able to keep the required parameters stable, and im getting pretty comfortable with it, yet i find my alk not in range every once in a while…testing low…