RO/DI Water

L

LovnChely

I purchased an RO/DI unit used from another member. I have changed all of the filters in the RO unit. I took the first 5 gallons and threw then out (had heard I should). I now have another 5 gallons, but I would like to test water before I begin to use it.

What tests should do?

Steph
 
if TDS is 0, wouldn't that mean no chlorine, phosphate, or anything else is in there either? Or are the readings not related?
 
Actually, there are small molecules like ammonia that can make it through a RO membrane, but are usually caught by the DI resin.
 
Taste test would be one option. Testing for nitrate, PO4, copper, ammonia, and chlorine would be good tests. TDS as well.
 
While it's a little bit of trouble (or quit a lot on some), I still prefer to get TDS readings for the water as it enters the RO membrane (after it's been filtered by the sediment and/or charcoal frontend filters) and as it exits the membrane (let it run a bit before taking the reading) and before it enters the DI cartridges. This will allow you to know the current level of functioning of the membrane itself as well as how much it's "off-spec" currently(especially if it was a used RO membrane). With the membrane input and output values, you can calculate the rejection ratio and see if/when the membrane itself should be replaced. A weakened/failing membrane will sometimes not be seen measuring only the DI/final water output as the DI resin will "soak up" whatever passes the membrane and it will just seem like you are going through a lot of DI resin unexpectedly. By taking the readings now, you will also have a reference for some point in the future to see how much it has degraded over some period of time/usage. It might be more trouble than it's worth, depending in installation, tubing, cartridge hookup,etc, but if possible I'd get them now.
HTH
Doug
 
"tds" =total dissolved solids - measured with a TDS Meter - I'm not sure if any of the LFS can check it for you. Maybe a member near you has one? They can be purchased quite cheaply on Ebay and are a good tool to have around.
 
TDS = total dissolved solids.. a measure of the particulate matter in the water.

There are handheld TDS meters that you stick into a cup of water to measure TDS, but what a lot of folks use is this little deal. It goes inline with your RO/DI and lets you measure TDS in two different places like source and output or after carbon and before DI (depending on where you install it.)
 
Thanks for posting the list.... I have one attached to my unit already, but wasn't sure what is was for....

So what should it read?

Thanks for helping everyone!
Steph
 
I came home tonight and ran my TDS meter. In reads 176 and out read 0.

Thanks for all the help..


We are going to celebrate no more going to the fish store to buy water....
YAY!

Steph
 
Great! Now add up all the gasoline savings and the worth of your time traveling to/from the LFS and the savings on the water itself.... and you'll feel even better and realize it truly is one of your greatest purchases.

Doug
 
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