High Alkalinity...again...

[callmedrlove]

I wrote a week or so ago about my high alkalinity (around 10 meq/L) and low calcium (around 25ppm). After doing about 60 gallons worth of water changes over the course of a week, and starting a Kalkwasser drip, I've got the alkalinity down to 5.5 meq/L and the calcium is up to 225 ppm. I know the calcium needs to be higher, and it's coming up slowly but surely. But, after I do about a 30% water change it comes down to around 5.0 for a while, and within 24 hours it's back up to about 5.5 meq/L. Other than more and more water changes, I don't know how to get the alkalinity to come any lower. I'm not adding anything other than kalkwasser to the tank. Is 5.5 meq/L still too high, or will this work? Any suggestions would really be appreciated, I don't really know what to do.

 

[Randy Holmes-Farley]

Yes, 5.5 meq/L is still a bit high.

Limewater/kalkwasser is not the way to supplement calcium in this case, and I expect that if it is all that you added, the 25 ppm calcium was not an accurate measurement. Limewater would boost alkalinity by an additional 10 meq/L if it boosted calcium by 200 ppm.

Calcium chloride is the only thing you should be adding right now until the alkalinity is down to 4 meq/l or less.

This calculator shows how much, and the article guides you through the process:

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm

Reef Chemicals Calculator
http://home.comcast.net/~jdieck1/chem_calc3.html

 

[callmedrlove]

Thanks, I appreciate the help. I think a lot of the calcium could have come from the fact that I don't really have anything in the tank other than coralline and snails using calcium, and my water changes likely introduced a decent amount of calcium while lowering the alkalinity. Just a guess as I don't know that much about chemistry. I just wish I had asked this about a week ago before I made my order to Marine Depot and ordered 2 kg of kalkwasser

 

[Randy Holmes-Farley]

OK, water changes would have boosted it. I didn't know you were doing them between the measurements.

The kalkwasser will be a fine supplement once the alkalinity is down and calcium is up. That is the way I supplement calcium and alkalinity.

 

[callmedrlove]

Yea, the way it went was like so: I realized that everything in the tank was being sluggish so I checked parameters, and realized alkalinity was through the roof. So I went to the LFS and tried to find a way to fix it. The guy said a water change and start kalkwasser, so I did that. The alkalinity came down a little bit after a 10 gallon change (it's a 65 gallon tank). The next day I did a 16 gallon change, then later checked alk and calc again, alk was down and calc was up. So a couple days later, I did another 16 gallon change, and checked again. Alk came down to 5.0, and calc was at 210. So two days later I did a 12 gallon change, and checked and the alk was up to 5.5 and the calc was at around 225. And that's where I am now, with another 20 gallons of freshly mixed saltwater ready for another change.

 

[Randy Holmes-Farley]

OK, I'd go with just calcium chloride until things are more where you want them, then switch over the the limewater/kalkwasser.