Thats my set-up and here is my problem.

I have been watering my plants with just tap water with 7.5 PH, and adding about a cap full of neptunes harverst fish emulsions for every gallon of water and 1mL of superthrive per gallon. This usually brings the PH of my tap to right at 6.3 before it goes into my soil, I thought that was acceptable but now my run-off is testing at about 5.9. I flushed 2 pots with plain tap water at 7.5 PH and it brought the runoff to 6.2 so i fed it with my 6.3 nutrient water and the runoff was 5.8 after that. I'm not sure why my readings are so low. The plants have only been in this soil for a week now and have been watered twice only with my nutrient solution with a PH 6.3 and the PH is already as low as 5.9. This just doesn't make much sense to me especially with the lime I added to my soil. I'm planning on getting some ph up and ph down but is that going to solve my problems? Am I going to have to end up flushing all of my plants?
Does flushing with PH 7.5 tap water change the PH of the soil if it doesnt have any PH up in it? what should the PH value be of my water with nutes before it goes in the pot and what should i try to get the run off water to be? If my ph has been low for a while, could there be problems from phosphorus, calcium, and magnesium not being taken up and should I shoot for an even higher PH to compensate for this?

I'm really hoping someone can help me get this worked out because the frustration of fixing my PH is driving me insane
KiNdBlunt Reviewed by KiNdBlunt on . Need to control PH -indoor -soil -Soil generic with perlite -Soil Additives: Lime, Bone Meal, Blood Meal, MG Organic chicken shit -Soil pH:5.9 -Water source: TAP -Water pH: 7.5 -Age of plant: 1 month -Type of fertilizer: Neptune's Harvest Fish emulsion -Rate of application: once a week Rating: 5