limewater Question

[Ehgemus]

Ok, about two months ago I started to use limewater for my top off, I am using 1 and 1/2 tsp. per gallon of pickling lime with r/o water. since the weather is starting to worm up my PH has gone up to 8.3 from 8.0, I guess because I have had the windows open more and there is more fresh air in the house, That will make the PH go up right? my PH is between 8.3 and 8.4, my calcium is 300, and my alkalinity 5.5 meq/L. My question is how do I get my calcium up to about 400? without razing my alkalinity or or PH.
I have a 46g bowfront with 60 lbs live rock, skimmer, 15g sump with fuge, five small fish and 5 corals, witch are all doing great.

 

[bertoni]

I would suggest dialing back the limewater a bit, to let alkalinity fall, and using a calcium chloride supplement to raise the calcium. You're probably right about the fresh air raising the pH. If the pH starts getting too high, you could consider adding vinegar to the limewater. This article talks about the issue:

http://www.reefkeeping.com/issues/2005-01/rhf/index.php

 

[XeniaMania]

What about mixing kalk powder w/ vinegar first? I've been doing that and my corals seem to be responding much better since I can dose that at a faster rate w/o the huge pH swing. I take a water tester tube, fill it with 10ml of vinegar, and add about 1-1 1/2 teaspoon of kalk, then just add regular water. In another article I read, they state you can even use tank water since the process now is not the same as trying to saturate freshwater w/ kalk.

 

[bertoni]

Dosing limewater will raise both alkalinity and calcium, and the alkalinity level is already too high in this case.

 

[XeniaMania]

But doesn't the mixing of the vinegar w/ it knock out some of the alkalinity properties? If I remember correctly dissolving in vinegar first releases more calcium ions and acetate ions. I don't recall the alk part..

 

[bertoni]

Mixing it with vinegar temporarily reduces the alkalinity. When the acetate is consumed by bacteria, though, the alkalinity is restored. That's why limewater is a good balanced additive. This article goes into the chemistry:

http://www.reefkeeping.com/issues/2005-01/rhf/index.php

 

[XeniaMania]

lol..eeek...I guess rice vinegar is no good..=X

 

[Ehgemus]

I thought alkalinity was good between 4-6maq/L
so what should I do, stop limewater until alk goes down and that will help PH also, and add calcium in the meantime.

 

[bertoni]

I target about 3.5-4 meq/L, which is the top of the recommended range. So,m yes, I'd add calcium while alkalinity falls.

This article talks about all recommended ranges:

http://www.reefkeeping.com/issues/2004-05/rhf/index.php