Kalc question
- Thread starter Lars
- Start date
It is certainly possible to raise Ca and Alk levels by dosing kalkwasser, but there are a few variables in play...
First, you're generally limited as to how much kalkwasser you can dose in a system based on daily evaporation and how well ventilated/aerated the system is (ie. gas exchange). The more evap you have, the more "room" you have to dose kalk. The better gas exchange the system has, the less you'll be limited by pH effects when dosing kalk (excess kalk dosing can rapidly consume CO2 in the system and drive pH levels up).
The other part of the equation is Ca and Alk demand of the system. In a system where demand is low to moderate and evap and gas exchange is high enough to allow for large doses of kalkwasser to be added daily, it would certainly be possible to add more Ca/Alk each day via kalkwasser dosing than the system was using. In this case you'd see levels start to rise. Of course, in high demand systems you often see the opposite problem. In these cases sometimes even maximum daily doses of kalkwasser are not enough to keep up with Ca/Alk demand and other means of dosing must be used instead or in conjuction with the kalkwasser (ie. two-part additives, Ca reactors, etc.).
HTH
First, you're generally limited as to how much kalkwasser you can dose in a system based on daily evaporation and how well ventilated/aerated the system is (ie. gas exchange). The more evap you have, the more "room" you have to dose kalk. The better gas exchange the system has, the less you'll be limited by pH effects when dosing kalk (excess kalk dosing can rapidly consume CO2 in the system and drive pH levels up).
The other part of the equation is Ca and Alk demand of the system. In a system where demand is low to moderate and evap and gas exchange is high enough to allow for large doses of kalkwasser to be added daily, it would certainly be possible to add more Ca/Alk each day via kalkwasser dosing than the system was using. In this case you'd see levels start to rise. Of course, in high demand systems you often see the opposite problem. In these cases sometimes even maximum daily doses of kalkwasser are not enough to keep up with Ca/Alk demand and other means of dosing must be used instead or in conjuction with the kalkwasser (ie. two-part additives, Ca reactors, etc.).
HTH
So, I guess you can increase Cacium levels by dosing Kalc. but it sounds like doing so would do more harm in reguards to Alk and Ph that would make it a prohibitive method of increasing Calcium. What is the best additive to increase Calcium without messing up other parameters? Two part?
Kalkwasser adds Ca and Alk in balanced ratios so if you're looking to raise Ca levels and not Alk you'd be better off making the adjustment with the addition of some Calcium Chloride or one of the off-the-shelf Calcium supplements. The Ca part of a two part additive would work as well.
Chris, how do you figure balanced ratios? If you want to raise calcium by 50 ppm (say 350 to 400) it'll take a certain amount of limewater depending upon your total gallons, now that same amount of limewater will raise the alkalinity by 7dKh !! (According to any one of the reef chem calculators). Now i know there's some underlying interaction between calcium & alkalinity but surely it can't be that much of an interaction to compensate for that large of difference. I brought this up with Randy over at RC, and the conclusion seemed to be the same, long term use of limewater really isn't that good of a thing.
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Kalkwasser, two-part additives and Ca reactors all supply Ca and Alk in similar ratios to how they are used by calcifying organisms (thus "balanced"). This ratio is approximately 20 PPM of Ca per 2.8 dKH of Alk.
In your example the initial condition is not ionically balanced. At a dKH of 7 your Ca should ideally be about 420 PPM. In a case like that you should adjust the Ca to 420 PPM with CaCl. From that point on you can use some type of balanced additive (ie. kalkwasser, etc.) to supplement.
As for long term use of kalkwasser not being a good thing, I think many would argue against that idea. There have been countless reefs over the last couple of decades using kalkwasser with no ill effects. In fact, Randy uses it himself.
In your example the initial condition is not ionically balanced. At a dKH of 7 your Ca should ideally be about 420 PPM. In a case like that you should adjust the Ca to 420 PPM with CaCl. From that point on you can use some type of balanced additive (ie. kalkwasser, etc.) to supplement.
As for long term use of kalkwasser not being a good thing, I think many would argue against that idea. There have been countless reefs over the last couple of decades using kalkwasser with no ill effects. In fact, Randy uses it himself.
I realize there is a balanced bit, and my example didn't have it exactly, but that shouldn't matter, 3 gallons of saturated limewater will raise the calcium by 50ppm, and the same 3 gallons of limewater will raise the alkalinity by 7dKh. Now it's true those calculators are a crude estimate, and there probably is some internal balancing issues going on with the molecules as you slowly drip things, but there has to be something to this that says "hey something is wrong here."
I think it's the word "balanced" that's causing confusion. You're referring to quantities of Ca and Alk present per unit volume in kalkwasser and I'm referring to the ratio of Ca and Alk present as it pertains to supplementation (ie. how will it be consumed during calcification). Not the same thing (and I don't disagree with you on that).
Either way, I think we are in agreement in responding to the original question that kalkwasser can raise Ca levels. I think we're also in agreement that if Ca is low and the system is not ionically balanced (ie. Alk is not as proportionally low as the Ca) it wouldn't make much sense to try to raise the levels with kalkwasser additions. Personally I would correct the out-of-balance situation with the addition of some CaCl and then resume kalkwasser dosing (and up the dose a bit to keep better pace with the Ca/Alk demand).
Hope that clarifies.
Either way, I think we are in agreement in responding to the original question that kalkwasser can raise Ca levels. I think we're also in agreement that if Ca is low and the system is not ionically balanced (ie. Alk is not as proportionally low as the Ca) it wouldn't make much sense to try to raise the levels with kalkwasser additions. Personally I would correct the out-of-balance situation with the addition of some CaCl and then resume kalkwasser dosing (and up the dose a bit to keep better pace with the Ca/Alk demand).
Hope that clarifies.
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