Randy..follow up to high CO2 in basement

[villanid]

Randy, I had written earlier about high CO2 level in my basement, where I have my tank, causing my pH to run low (7.79 - 7.89). By running an airline from my Durso standpipe to the outdoors I now have a pH of 7.90 - 7.99. I use Oceanic salt. My calcium reading (Salifert) has been high 550-560. My alkalinity has been around 8.2-9.5 dKH. I have yet to add any corals or fish to my tank. It has been cycling for 2 months. Do you think these conditions (pH, alkalinity and calcium) are suitable for maintaining an sps reeftank, if I can keep them stabilized?
Also, yesterday when I did a water change, my tank pH was at 7.94. My new saltwater was at 7.89. Soon after the water change, I developed a moderate amount of "snow" floating about. Nothing settled (yet). With the conditions described above what is the cause of this? Will it go away on its own or should I do something?
You've been a big help with the start up of my tank. Thanks and Happy Holidays to you, your family and your corals!!
Dave

[Randy Holmes-Farley]

Yes, those values are suitable.

How did you plan on supplementing calcium and alkalinity? If you add a CaCO3/CO2 reactor, the pH may drop further. Limewater may be a better choice for you.

I'm not sure why you developed a precipitate. You mixed together two clear salt water solutions,and later got some precipitate? Nothing else was added?

[villanid]

No, nothing elso was added. I didn't tell you that I do currently dose a steady kalkwasser drip.
I thought that since my calcium was high (550) combined with a low pH that this was the cause of the precipitation. Would a high or a low pH cause precipitation? Also my dKH is actually 9-10.
Should I try to get my pH higher than 7.90 - 8.00 or is this an ok range?
Thanks

[Randy Holmes-Farley]

Would a high or a low pH cause precipitation?

High pH causes precipitation. The higher it is, the faster it is, but it is not usually a big problem even at pH 8.5.

If the alkalinity is 9-10 dKH and the pH is around 8, that should be OK. I wouldn't agonize over getting it higher. There is a good chance that the air in your house has elevated CO2, and it is hard to correct for that in ways other than limewater or more aeration with fresh air.

This article may help you undewrstand the pH issues:

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm