Should my EC be changing?

I go by ppms, but yes, I like to see the EC slowly go down over the course of a week. That tells me for certain that the plant is eating. Especially when dealing with any sensitive or finicky strains.
Some like to see it remain constant. That's ok too. It would then mean the solution is balanced for the uptake.
A constant rise wouldn't be a good thing though.

 

If the tds is t changing the plant isn't taking water, the change is how you grow in hydro...


nonfiction's multi-strain grow

 

Well, you can visually tell how much water is missing. That tells you the plant is drinking. TDS readings tell you it's nutrient uptake.

 

Op has invested a lot in hydro stuff to be surprised by ec changes lol if I can suggest a read in the hydro sticky there's a post about ppm and finding your plants guidelines, for hydro with a res it makes it so simple for you, for you can't find lemme know and I'll hop on a pc and find for you, you def want to understand Ppm changes to keep your plants fed right to the limits, taking full advantage of that awesome set up you have


nonfiction's multi-strain grow

 

Here's the link

How To Determine Your Plants Preferred Nutrient Strength


nonfiction's multi-strain grow

 

It's better if it isn't changing as it means the reservoir EC is the same as what the plant is taking up. If the reservoir EC is too high, it will continually rise due to the plant taking up a weaker solution, leaving behind more nutes/water ratio.

Have a look here for a more in-depth explanation How To Determine Your Plants Preferred Nutrient Strength