Molasses is a replacement for CalMag and SuperThrive. (Grandma's or Brer Rabbit are common in growrooms nationwide) It provides calcium, magnesium, iron, carbon, carbs and some micronutrients. Acts like a 'nutrient assistant' supposedly adding to the effeciency of most nutrients.

It's a very bad idea to switch between ferts. Jacks (the old Peters line) isn't the best fert to begin with, or you wouldn't need to switch back-n-forth. It's by no means the worst, but it is similar to Miracle Grow All Puropse, which I use when temporarily out of my Fox Farms line.

With Dynagrow Growth formula, it says on their website that the components will hold water longer, but both will add to salt build-up in the soil. Regular monthly flushes with properly ph'd water helps to release the salts and prevent salt build-up common with inorganic nutrients. I flush on the first of every month. (easy to remember)

I'd pick a nutrient and stick with it, flush with plain properly ph'd water, and start with the molasses at 1 tsp per gallon, once a week. And for goodness sake, follow the directions. Most directions give a weekly feeding schedule, but some are for a 10 day to 2 week period. This means plain, properly ph'd water between feedings, when necessary.

In the summer I don't usually add perlite, and if I do it's not much. In the summer you'll want a little bit of moisture retention. In the winter, I add up to 20% perlite, depending on the soil used...because the soil will hold moisture too long which can damage roots and throw-off watering/feeding schedules. Plus, the more perlite you add, the easier it is for the nutrients to just run right through the medium and end-up in the drip tray, wasting nutrients and money. Your growroom might or might not be a stable enviornment throughout the year, but this does display the need to be flexible and understand the seasonal changes.