Why is my TDS fluctuating?

[KStatefan]

It was 0 lol.

There are 3 tds numbers that are important to know how your RODI system is running

Membrane In (Source Water)

Membrane out or DI in

These two numbers are used to determine the rejection rate of the membrane to see how well the membrane is working.

The third TDS DI out is used to tell how your DI resin is working.

I am assuming you only know two of them Membrane Out and DI out. I am also assuming when you said "In 7 out 3." That was DI in/membrane out 7 and DI out 3.

You can make some approximations without know all three. Most water systems are going to be fairly stable on TDS of the source water so you can look at the DI in/Membrane out number and if it is going up over time the rejection rate of your membrane is going down and might need replaced.

@Buckeye Hydro has a nice write up on some of the common terms of a RODI system.

He also had DuPont Filmtec membranes on sale earlier this month but not sure if that is still on.

 

[stupidfishguy]

Don’t worry the area is getting rain next week. I live in Hamburg, but I am originally from the central part of California. This drought isn’t even a bump in the road compared to what they experience yearly. 5 years ago my parents had to re-drill their well because the water table dropped so badly from no rain.