Sure wish you folks that offer advise would give the correct advise.
6.3 to 6.8 ph for peat-based mixes. Keeping it below the low range and you will lock-out nutrients.

Soilless is a long-used term denoting any potting mix not made from garden dirt. The most common are peat moss based mixes, and are usually buffered to a near-neutral ph. Trying to lower this ph is unnecessary, unwarranted and depletes the buffers in the soil quicker. Sunshine is a peat based mix.

Then you have coco, hempy bucket, aero and hydro. Methods I do not use, but I hear they require a lower ph.

What do the instructions on the bottle say about dosages and frequency of use? Most nutrient products give a weekly schedule. (one application at recommended dosage per week) None I've come across are a 'feed every watering' formula.

Your growroom would benefit from proper lighting. Incandescents, HQI's, grow spotlights are all garbage in the growroom. Too much heat, wrong spectrums. CFL's, fluorescent tubes or HID lights are optimal. (in the correct spectrums, of course)