TDS Meter reading

[AngelPete]

what is the highest number my TDS meter should read before changing my RO filters ? I just replaced the batteries on the meter and I'm getting a 15 reading on the output water. I guess its time to replace the catridges?

 

[stcreef]

If you replace the batteries, you should recalibrate before trusting it. This goes for any piece of equipment. Once its calibrated, then test. I usually change my filters once I see any rise from 0.

 

[BobCReef]

i change mine at 2. Did you change the batterie because the number was high. or it just stopped working

 

[AngelPete]

the meter just stopped working!. well after running it for a while with the new batteries, the reading is now zero. I guess it had to recalibrate.

 

[pitogo]

Is that 0 ppm for RO output or from RO+DI? If so what membrane are you running. Tap is around 220, 3 pre-filters then RO comes out at around 4-15ppm then the DI brings it down to 0 ppm.

If you replace the batteries, you should recalibrate before trusting it. This goes for any piece of equipment. Once its calibrated, then test. I usually change my filters once I see any rise from 0.

 

[stcreef]

0 from RO/DI. I run a Filmtec 75gpd membrane. I have rather clean well water that is typically <100ppm. If I see a creep after the DI, then I will check the incoming and out from the membrane. I know this membrane has a 98% rejection rate. So if I see less than that, then I will try a long (30 minute) flush to see if I can bring it back. If not, then all filters/membrane get switched out. BTW, because of my low incoming ppm, my DI filter will outlast my membrane. But I switch the DI and pre filters whenever I change the membrane.

For a few minutes work once a year (about), it assures I am not adding anything unwanted into the tank. I always keep an extra set of filters and membranes on the shelf.

 

[pitogo]

Thats cool! I bought the 150GPD membrane from AWI. Its supposed to have a 98% rejection rate. So far I'm liking it for its speed and for the output. My incoming is tap is hardwater with lots of calcium and over 200ppm so the output from the membrane is acceptable. I do flush but next time I try the half hour flush.