Perlite does not affect ph.

Potting soils and soilless potting mixes are usually pre-buffered. The more important ph numbers will come from your water. A ph pen is the most valuable troubleshooting tool you can get as an apprentice. It'll ph anything liquid regardless of color of the water. Handy for ph'ing ingoing water and nutrients, and finding out runoff ph. (shows the interraction between the water, medium and additives)
Next best would be an aquarium ph test kit. At least it shows the ph or your water before you add nutrients. But any tinting of the water can and will skew the results.
One I would never purchase (again) is a soil ph probe. Have never met one that did it's job, and doesn't work for ph-ing water. (jusy my personal preferences)

If for instance, you get an aquarium ph kit, you can ph your water to the high end of the ratio, at least on feeding days, and you should be fine. Most nutrients lower the ph a tad.

Even if fish emulsion is labeled "deodorized" it still stinks. Would be careful with it when getting close to switching to 12/12. Organic solids take a long time to break down, and can still add (small ammounts of) nitrogen through flowering.