PPM of water rises?

It seems like the PPM in my reservoir goes up after leaving it for a few days, instead of going down.

Using R/O water with a PPM of ~35 and nutrients to raise the PPM to 400, the PPM is now 800 in one reservoir and 1,100 in the other. I put the same amount of nutrients give-or-take in both.

What's causing this and what does it mean?

What kind of containers, media? Plastics should be PP5 or similar, media should be inert.

I use PVC pipes, a regular IKEA plastic box and a Flexitank.

ChenBenTz said:

It seems like the PPM in my reservoir goes up after leaving it for a few days, instead of going down.

Using R/O water with a PPM of ~35 and nutrients to raise the PPM to 400, the PPM is now 800 in one reservoir and 1,100 in the other. I put the same amount of nutrients give-or-take in both.

What's causing this and what does it mean?

Click to expand...

As stated above.....We need more info to help diagnose what`s going on.....Are you recirculating your setup ?....What size are your rez`s ?....and....

Do you use small powerhead pumps to keep nutrient solution stirred to keep shit from falling out of suspension/precipitating ?....Larger rez the better for buffering , but if your plants aren`t eating then ppm`s rise and ph drops....

Without more info , X can be anything....I see you understand and make note of in a dialed setup as plants eat ph rises and ppms drop , so there`s definitely something makin shit go backwards and sideways....anyways....Good luck and.....

Peace....DHF.........