Nanashi's First Grow 0_o

Im having a problem that seems to be a calcium deficiency. I decided my problem is because i have a 56 GAL RES and i only change 40 GAL 1 time a week. So i did some plumbing upgrades to allow a complete flush. (It is in the time lapse) Ordered Cal Mag extra From Advanced Nutrients and did a foliar feeding with Epsom salt for now while i wait for it to come in. (hope the fact it was scented does not come back and bite me.) Im adding a 2nd 1000w HID Light This Friday (And gonna try and make one Light mover run Two Rails .... in parallel MWAHAHAHA The CO2 Regulator i was using had a o-ring go bad and filled the room over 10,000 ppm 0_o P.S. im in week 7 of veg and don't know how to change it / don't have the time to figure it out, so im leaving it for now and deal with it later.