Alk - Ca Zone 3 Question

[pnwreef]

I'm new to Reef tanks so the chemistry part of the hobby is still new to me.

My tank (30G + 15G sump fuge) is 6 weeks old - I have about 50lbs of liverock in the system and a DSB.

I replace the water I loose to evaporation during the night with a DIY auto-top off system. The replacement water I drip is lime water - I use Ball's Pickling Lime (1tsp per gallon). I think Ball's is Calcium Oxide - not sure?

My Alk is 4.57 meg/l and it has been climbing ever since I started testing it on 5/15 - I started adding lime water on 5/15 as well. My Ca level has also been climbing since I started testing it 5/15, it has gone from 310ppm to 370ppm. I read Randy's article on Alk and Ca and I think these levels put me in Zone 3 - the most difficult to correct.
http://www.advancedaquarist.com/issues/nov2002/chem.htm

This is my question. Should I leave the system alone and hope that it comes into alignment over time? Or, should I add some Kent Liquid Calcium to bring the Ca levels up? I'd prefer to leave it alone but I'm not sure if the lime water by itself will bring Ca up to 400. I'm also worried about the high Alk reading. Should I be.

Any help would be appreciated.

- PNW REEF

P.S. I make my water up with Instant Ocean and I don't have a Magnesium reading.

[Randy Holmes-Farley]

I think Ball's is Calcium Oxide - not sure?

I expect that it is calcium hydroxide.

Should I leave the system alone and hope that it comes into alignment over time?

No, that won't happen unless water changes correct it. I'd suggest adding calcium chloride to bring calcium to 420 ppm. The article describes that addition in more detial. :)

[pnwreef]

Originally posted by Randy Holmes-Farley
I think Ball's is Calcium Oxide - not sure?

I expect that it is calcium hydroxide.

Should I leave the system alone and hope that it comes into alignment over time?

No, that won't happen unless water changes correct it. I'd suggest adding calcium chloride to bring calcium to 420 ppm. The article describes that addition in more detial. :)

Thank you for the suggestion. I added Kent Liquid Calcium (calcium chloride) to the system minutes ago. Do I continue adding the recommended dosage until I get to 420ppm? Will the lime water be sufficient to buffer the system? I don't have any buffer on-hand.

PNWREEF

[Randy Holmes-Farley]

When making substantial corrections, you can typically ignore manufacturer dosing recommendations as they relate to maintenance, not raising levels. However, you don't have much to go, so you don't need that much. If it doesn't seem to be coming up, just add more.

To raise calcium by 100 ppm with that supplement, you'd need to add about 1/1000th of the tank volume.