GHL Conductivity probe / Alarm

[Mark E]

I know this is nerdy…

I want to use a conductivity probe on my RO system to tell me if the DI resin needs changing (I used two DI pods so the probe will sit between the two.

OK Conductivity measurement is a dark art but I don’t need (a) stunning accuracy or (b) 24/7 monitoring. All I need is when the RO is running an alarm to say the conductivity is above 2 micro Siemens / cm which is at the bottom of the freshwater detection range.

But, I only want this to happen when the RO is running, and preferably after there’s been a decent flow past the probe to prevent false alarms. Happily I can be 99% certain that at 2pm every Thursday those conditions will be met.

So, can I use Programmable Logic to detect the Conductivity Probe reading at the specific time (2pm Thursday) and set off an alarm if it’s high? I don’t believe it can be a Conductivity Alarm because that’s only capable of being on or off, not controlled by a timer, but will PL work in this way?

Thanks

 

[Solo McReefer]

The color changing resin and TDS meter are insufficient?

 

[Mark E]

The color changing resin and TDS meter are insufficient?

Tricky to see through the brick wall in the way!

The RO kit is in a garage, the mixing tank and sump are the other side of the wall. So not only do I have to be home when the RO runs, I have to open up the garage and check the TDS meter, and mostly that’s to see a string of zeros.

Even if the TDS meter reads 1 or 2 I’ll do nothing at the time I check it (because the second DI pod will mop up those TDS). I’ll wait until it’s convenient to change resin - maybe the next weekend, but there’s no harm in leaving it a week or more, it’s a messy job.

 

[ingchr1]

@Lasse

 

[Lasse]

K Conductivity measurement is a dark art but I don’t need (a) stunning accuracy or (b) 24/7 monitoring. All I need is when the RO is running an alarm to say the conductivity is above 2 micro Siemens / cm which is at the bottom of the freshwater detection range.

But, I only want this to happen when the RO is running, and preferably after there’s been a decent flow past the probe to prevent false alarms. Happily I can be 99% certain that at 2pm every Thursday those conditions will be met.

This two BOLD units is not the same 2 ppm TDS is around 4 micro siemens/cm.

Sincerely Lasse