Hey algreen, don't be afraid to post a question if you can't find the answer, good to hear you did a bit of searching first :thumbs:
Using BioGrow and BioBloom I've noticed in the 5th-7th week you really need some kind of calcium and magnesium supplement, they don't seem to have anything in them to help with this. I bought my Cal/Mag from Amazon, if that's an option then I'd say buy it there, that'll save a lot of foot work looking for it in the shops.
If not then a cheaper option is to save your eggshells and either slowly dry them out on the windowsill until you can crush them easily, or put them in an oven on a low heat for about 10 minutes. Put them in a bag a smash the hell out of them with a rolling pin or something.
You can either sprinkle this dust on top of your soil or do what I do and use a chopstick to poke deep holes in the soil and fill it back up with shell-dust, this gets it down in the roots nice and quick. (About 2-3 eggshells per 10 litre pot)
That sorts out a cheap Calcium supplement.
For magnesium I either use Epsom salts which you'll find in a health store, they're used as bath salts. I can't remember the correct measurements but I tend to add 1 teaspoon per litre of water and that sorts and problems out.
Another magnesium option is using molasses (Black Treacle (like you'd bake a cake with)), again, 1 teaspoon per litre on every other feed has seen me well up until I bought some Cal/Mag.
A combination of Epsom Salts and molasses is something I often feed to my plants.
Hope some of this helps
:smokebuds: