quick question about water level and ppm

I searched for about an hour and didnt really see the answer to my question. Hypothetical scenario..

Lets say that your water level is 4 gallons 500 ppm
24 hours later your water level is 3 gallons 600.

being new to DWC this would mean my plant is drinking more than eating. However, my question is would I need to add back 1 gallon of RO water to get my "true" reading? For instance adding 1 GAL of RO water would probably make my reading 4 gallons, 400-450PPM. Which one is my true data? After adding the lost gallon back and finding my reading of 400-450PPM does that mean it's really not drinking more than eating and that I should increase feed?

I'm just trying to dial in my setup. Thanks for all the help thus far.

The reason I ask is because RO only has, well for me, 20ppms. So by adding back the gallon of water to make it my starting level of 4 gallons and the PPM showing a decrease of 100 PPM I feel that would be my true reading for the bucket as a whole right?

you were correct until you started calculating your add back stuff.

500 was too strong. try 300 and see what the ppm does.

Ok that's what I assumed. Do you have any idea why it could be 5.9 one day and drop to 4.5 in two days? I think I need to up the PPM

Aviatorshades said:

Do you have any idea why it could be 5.9 one day and drop to 4.5 in two days?

Click to expand...

kinda depends what your EC/ppm is.
if you are 500ppm and it drops that much, maybe root rot.
if you are only at 50ppm and it drops that much, the water just doesn't have enough "stuff" in it to keep pH stable.

Creature1969 said:

View attachment 4785637

Click to expand...

This is what I use

rkymtnman said:

kinda depends what your EC/ppm is.
if you are 500ppm and it drops that much, maybe root rot.
if you are only at 50ppm and it drops that much, the water just doesn't have enough "stuff" in it to keep pH stable.

Click to expand...

I'm at 5.7/1100 ppm and it drops about .3 every day

Aviatorshades said:

I'm at 5.7/1100 ppm and it drops about .3 every day

Click to expand...

If your ph is dropping and ppm is steady you have something in your water thats not good.
iME ph dropping raises big concerns.Now everybody has different systems/nutes so theirs variables but something is not right.