PPM increases and ph decreases after feeding every day...

Ok so Im not really a novice when it comes to growing as I have grown plenty of good stuff and gotten good results...

But I have been noticing that after I make my solution to about 1250ppm and 5.9 ph, about 2-3 days later ppm has gone up to 1400 and ph was down to 4.5

Are the plants only drinking the water there-for increasing ppm and lowering ph (as water seems to be more acidic then the core nutrients)...

Is this normal as I never really checked it before, but I have to keep adding water and silica blast to correct the ppm and ph.

Is this due to nutrient lockout? maybe rootbound? they are in 3-5 gallon containers with perlite #3.

This is happening in flower, but also happening in veg as well.

TIA.

Does this not happen to anyone else here?

What kind of system are you growing in?

This is completely normal, although not necessarily wanted.
Your res is running 'hot', meaning you your plants take up more water then they take up nutes, thereby increasing the nute concentration (increasing ppm's/lower ph)
Some will tell you that you are feeding too much, but I don't. Sure, it is an indication that if you do not start adding some water back each day you might run into some issues as it relates to burns etc.
Here is what I would do:
-If the plants are not burning & look happy at the current ec (ppm) after you change your res., then just add back water every day to the level it was on the day of the res change and measure the ec again to make sure that they are eating. You may still have to adjust the ph a tad, but it is no big deal. You will notice that at about mid week the trend will reverse and your ph will slowly rise as the nutes are getting depleted.
- If they are burning (look at the tips) you will have to reduce your nute concentration until they are happy and then just maintain like I said above.

My res runs always a bit 'hot' without adding back water and I like it that way! If my res. was perfectly balanced on the day of my res change, my nutes would be too weak as the week goes on. and I would have to start adding back nutes etc. Currently my dehumidifier adds back about 1.5g per day and my plants drink about 2 gallons to 2.5gallons a day, which maintains me a balanced res. My ec ends up about the same were I started at the end of the week with only minor adjustments while my res level will have dropped about 6-7gallons.

Hope this helps.
Kind

its a pearlite mix in a drip system. Seems like every day weve been having to add water back cause ppm would increase by 200-300 ppm and ph drops to low 5's. But we just add more water and about 150ml's give or take of silica blast to adjust ph back to 6.0 and they seem to be responding well. the leave tips are curling down a bit but no signs of nute burn. Been at about 1500ppm going into week 5 now and they are all handling it like champs (except the sweet tooth is a weak strain to begin with).

The niceguy, OG kush and GDP are really starting to look good though.