Runoff water of soil is 4.8ph!?! Wtf....

So I have been using Happy frog soil made by fox farm.

I have two Og plants in 1 gallon pots and yesterday when I went to check the PH of the runoff water, it was at 4.8!!

I flushed them with 6.6PH water to try and help correct it but it took about 5 gallons to get the PH just to 6....I didn't want to run too much water through them.

Anyways.....WTF! Happy frog soil is balanced with dolomite lime and should be fine and yet the PH run off is 4.8?!

Luckily the plants didn't get messed up at all but I imagine the Ph has been sitting like that for a few days. The fact that they are okay is amazing the hell out of me.

My question is: is the runoff water supposed to be the exact PH of the soil, and should it be very close to the Ph of the water you water your plants with?

Any help or info is much appreciated guys, thanks.

if you water with 7.0 and the run off is 4 then that means that soil is very acidic and has changed the acidity of the water you put in.