RO/DI Units

Until I get the spectrapure filters and resin I'll keep using prime to be safe then.

 

A good handheld TDS meter is your best friend. you can pretty much rest assured the water has no contaminants as long as the TDS is 0 in finished water. When it starts to show anything other than 0 it is time for a DI replacement and to monitor the rejection rate or condition of the membrane.

 

I've got a dual in line TDS meter. I went 3 days without making water and ran it yesterday and for a few minutes it showed 1 ppm tds then went back to zero. The unit is only few weeks old. So if tds meter shows any reading other than zero I should replace the di resin first? The tds before filtration is about 530, crazy.

 

You are seeing what is called TDS creep when the system first starts up. this is normal and should drop back to 0 quickly.
If you want to extend the life of your DI resin install a tee and ball valve between the RO and the DI and flush the initial few ounces of high TDS water to the drain each time you start the system so it does not hit your DI.

It when you start seeing anything other than 0 TDS once the system has been running about a minute or so when you need to start looking at the resin replacement and membrane condition.

I own two dual inline TDS meters and am not a fan of them. I don't even turn them on anymore since they lack the accuracy of a handheld and they limit you to two readings when you need three TDS readings to troubleshoot a RO/DI system, tap TDS, RO only TDS and final RO/DI TDS.

 

What and how often is the maintenance? I'd love to make my own s/w and top off water. Esp cause closest petstore w mixed is 20+ miles

 

The recommended maintanance is to change the sediment and carbon block filters every 6 months at a cost of maybe $12-$20 and to disinfect the system annually, usually a a filter change since you will already have it apart. Test the TDS frequently so you know the condition of your RO membrane and your DI resin and change the DI when you start to see anything other than 0 TDS and thats about it.

 

Awesome thank you, so easy!