Dumb Question

[Lampshade]

nitrate spikes can cause a drop in PH, and with a big algee bloom the nitrates can be used up by the algee causing readings to be low. Just a theory, i'm sure some of the more advanced guys can give a better answer.

I had a better article about this, and can't seem to find it anymore, but here's something close:
http://saltwater-aquarium-guide.net/...water-aquarium

This one suggests that excess CO2 buildup could cause both conditions. Would also make sense now that it's cold out and your windows would be closed:
http://www.advancedaquarist.com/issu...e2002/chem.htm

anyways, best of luck, hope things work out.