You are not alone with that feeling. When I used FF ocean forest ppm readings of 2400 were normal especially early on in the grow. What the reading is telling you is there are enough nutrients in the soil and very little if any needs to be added. As @OGIncognito suggests, you can water only a time or two to let the plant consume the nutrients in the soil. Then, repeat the runoff test to see if it is time to add nutrients again. PH of 6.5 is right where soil needs to be. A probe style PH pen is not accurate enough so rely on runoff to measure ph.
When trying to figure this stuff out (which I have not to the extent I want to) I found this article to be useful and one that made sense to me.
likewise on this Grow Sis and appreciate the article 