ro/di ????

[chris1017]

I just bought new filters, 75 gpd membrane, ad on di kit and flush valve for my ro unit. I set everthing up and tested my tds.

Tds at tap is about 150ppm, after carbon and membrane 15ppm and after di I read 0ppm.

since all looked good I made a 30 gallon batch of water, but when I checked my tds it read about 3ppm. why would it go from 0ppm to 3ppm.

the only thing I noticed that I was not sure of was the di canister only filled about half way when running it. this is my first time using the vertical add on and I was not sure if it was supposed to fill all the way.

any thoughts on this would be helpful.


thanks,
chris

[sjm817]

150 tap and 15 after RO is not that great. I would expect low single digits. What brand membrane? Where/how did you measure TDS of 3? A container can easily add some TDS. You should measure the DI output in a clean glass that has been rinsed a few time with the RO/DI.

[chris1017]

filters came from bulk reef suply. I measured in a 30 trash can that I use to hold my water and from a salt bucket I filled.

[Just2Many]

Well did you wash your hands? Any little contaminates can lead to a small increase over all.

[sjm817]

If the trash can, and the salt bucket had some small amount of anything in them it would raise the TDS.

[LifeAquatic]

Make sure you check the water in a clean glass. If you poured it into the mixing container and checked it there might have been some previous contaminet in there. Also, make sure you use .5 micron sediment and .5 micron carbon block filters. They will get your TDS to 10 or so after the RO membrane. Using better pre filters will help your DI chamber last longer. I actually run a 6 stage RO/DI and get about 1200 gallons of pure water with no filter changes. Here is my combo. (.5 sediment, .5 carbon, .5 carbon, 90GPH ro membrane, Max Cap DI, Silica buster DI. ) In that order. Works great!

[chris1017]

I'm using a 5 micron and 1 micron carbon and
a 5 micron sediment.

As for the tds, I'm thinking it's the containers.
Thanks for the idea's


Chris

[chris1017]

though I am still questioning if the di canister only filling half way is ok.


chris

[sedor]

The small tds reading is probably coming from the trash can its being stored in. Only way to truly avoid this is to get a food grade container. That being said, its harmless since your filter is removing 99.9% of the bad stuff in the water.