RO-DI Water Questions

[Ssdlm5]

I found this really weird. I built a DIY ATO system and I do use RO-DI water. When the water comes out from the RO-DI system it is at 0 ppm. I use a Rubbermaid container to hold the top off water next to my sump. I have a rio 600 pump in there attached to the float switch.

Before I did'nt use to have a cover on the container holding the fresh water. But after a few days I would take my TDS meter and check the water and it would be like around 40+ ppm. I would see like some kind of build up in there also. When i touch the tubing that is coming out of the rio 600 it would be kind of slimey. So then I put a lid on top of the container for a week and I check the water again. It was at 21 ppm. Why does this happen? Is the water sitting there for too long? Well the top is not completely sealed tight because the tubing has to come out through this little opening. Please let me know whats wrong.

 

[MikeyZO]

Was this a new rubbermaid container? Did you wash it with soap or something and maybe not rinse it out well enough? Or did you have something else stored in it?

You could try putting a small powerhead in the container so there is a bit of circulation. Incidently, this is why I have been a little reserved about using rubbermaid containers.

 

[meschaefer]

A couple of things, your Rubbermaid container, power head and tubing are not sterile. Especially after leaving off the top, allowing contaminants to get into the water. The slime stuff is probably bacteria.


Other things to think about, is if you put your hands into it (grabbing the pump maybe), or anything else will also tend to raise TDS. As an example, my RO/DI container always has a small TDS reading because I scoop water out with a measruing cup (to top off a holding tank), I also use that same measuring cup to measure salt.

 

[Widdy]

Check to make sure if your Rubbermaid bucket is made of food grade plastic. Otherwise the DI water will start leeching chemicals back into the water after a few days. The blue 5 gallon jugs (Poland Spring, Deer Park, etc) are food grade. If you need a bigger container, check http://www.globalindustrial.com/gcs/product/productInfo.web?infoParam.itemKey=30157196.

 

[ecvernon]

i have a similar setup and had the same problem. my tds in the reservoir was not as high though. what happened to me was that after the ro/di stopped running for a long amount of time the first stream of water will come out with a high ppm which was not zero. after about 5 gallons it will be zero ppm. now after the ro stops running before i refill the resevoir i run off 5 gallons first to ensure pure water is whats coming out. for me the source was after the ro/di stopped producing it will start back up with higher ppm.

also if ther is any light source the slime could also be algea