It is more readily available online. Go to ebay and search botanicare cal mag or calimagic. You can even buy small quantities for a decent price. Remember to filter to "buy it now" and select to sort by lowest price first.
You should be doing nute watering then a plain watering then nutes again etc.. a tsp of cal mag per gallon every watering or every other plain watering. Personally I use a tsp every watering. I use botanicare calmag that I get on ebay and have excellent growth.
One of the best strains I've ever grown. Really easy and it loves nutes. Very frosty and a high in thc content (up to 25 or so). Only thing is after about an hour you get tired unless you keep smoking more, very heavy body stone. Earthy and coffee mixed with fruit taste. Real winner for indica...
Right now growing thc bomb x reserva privada og kush if anyone's interested. They just started week 3 flower and is growing vigorously. Will come back to this thread with pics when things look more funky.
Your roots will be working to stretch into the new area it's been allowed while it tries to intiate flowering. It's just too much for it at one time imho. I would at least give it 2-3 days to see if the plant was shocked during the transplant and look for signs of growth. If it grows a bit...
You should wait. Your plants are getting used to the soil. If they have to adjust to new soil as well as a new light schedule at the same time it could stress them very much.
Yes, in weeks 3 and 4 of flower all three are used together. Big Bloom is organic and contains the micronutrients. Grow Big and Tiger Bloom are the macros.