You're about 1-1.5 hours south of me It's bloom time!
Shultz bloom plus is a granular sold at home dePOT that is mixed with water before use and becomes essentially a liquid fert. But you already have a fert in there, so only add more if the plant looks hungry.
If you are near I-91, head up to Holyoke MA and there's a small but well-stocked hydro shop on Rt. 5 just heading north out of the city. It's called Liquid Sun and they stock a variety of 'specialty' ferts.