What is it about the 2nd to 3rd week of flower? If I'm gonna have problems, that's where it starts.
I use
Botanicare Cal-Mag. I've been researching a "home grown" substitute for cal mag, but have yet to find a decent one. A guy (An organics
guru on SEVERAL forums) once posted about steeping eggshells for a while and using that in combination with Epsom Salts to get the same result.
I've been told that I'm wasting time and money using
Cal-Mag since my water is so hard, but the girls seem to love it, that's for sure, and that being the case it's worth it if only for
my own benefit.
As for sources for
Cal-Mag, there's always the 'net. I hate buying shit over the internet, but sometimes you gotta do what you gotta do.
Don't forget the Silica while you're at it. I use
Silica Blast (
Botanicare). I used it when the girls were looking kinda puny a couple grows ago, and it sure seems to make a difference. I used it to help with "rubbery" stems and it took care of that and acted like a shot of Geritol tonic. It just seemed to improve the overall sense of well being in the room.
Good luck!!!