This is interesting! Iíve been using PPS for about three years for pretty much the same reason. Iím interested in an Amazon biotype; so, I need acid low GH water. My city water is pretty hard so I have to mix RO/city at 4/1. This is a lot of RO; so, I can only commit to 20% water changes per week. I do my 20% water changes and daily fertilizer feeds and I have no problems except a lot of plant growth that needs to be mowed each week.
I have really accurate and precise testing methods for KPN and test about once a month or more often when things look bad. Mostly this is for information only but occasionally it verifies what I see in my tank. My KPN is very low by EI.
I think most people way over fertilizer their plants and can be successful with much less KPN.
If you play with chemicals you should know some chemisty.