Filling my ATO bucket I'm getting 0 TDS. But by the last half gallon or so before I refill it, I again tested for TDS and am getting a reading of 002. Why? And is this bad? This is a food grade container.
Are you putting anything other than RO water in the bucket? Such as your hands, a siphon hose, smaller bucket to scoop water, ect.? Any of those things (and more) can add TDS.
Hi Jamie, my understanding is that when fresh RODI is created, it is an unstable state of water as the water is being stripped completly. Hence, to achieve a stable state it starts to absorb stuff from the air and you start to see a little bit of tds
I thought by having an air tight lid & a hole just big enough for the tubing would keep stuff out. Guess not-lol. Once I fill the ato I put nothing into it. It doesn't get opened again until refill time.
Hi Jamie, my understanding is that when fresh RODI is created, it is an unstable state of water as the water is being stripped completly. Hence, to achieve a stable state it starts to absorb stuff from the air and you start to see a little bit of tds
I believe this is one of those inaccurate theories that gets cited a lot. If I recall correctly
@AZDesertRat
has posted on this very topic (possibly on a different forum).
My guess is that the food grade container is leaching something that's well... food grade.
I thought by having an air tight lid & a hole just big enough for the tubing would keep stuff out. Guess not-lol. Once I fill the ato I put nothing into it. It doesn't get opened again until refill time.
This container is your ATO reservoir? Then you have a pump, the tubing connected to the pump and the electrical cord for the pump in the reservoir. Any or all of these could be providing the small amount of TDS you're getting.
There's in interesting article in the latest CORAL magazine that talks about how flexible tubing leaches plasticizers into tanks. I'm not sure if plasticizers are considered TDS, but the article provides evidence that the flexible plastic we use in our tanks is not inert.
Test the water sraight from the RO/DI unit as it is producing the water then test the container and compare the two readings. If the RO/DI membrane and resin are still good the reading directly from the unit will still be reading 0 regardless of what the container reads. If the container is brand new it mught be wise to do a good rinse with a few spoonfulls of bleach in some RO/DI water then a rinse with a vinegar/RO/DI mixture followed by a quick RO/DI rinse just to make sure the plastic molding release agents and oils have been cleaned off the plastic.
If it still reads some TDS it could be the container is releasing small amounts of contaminants or it could be as simple as CO2 in the air etc. At a reading of 2 I would'nt be alarmed but it is worth watching. I have RO/DI sitting in a Rubbermaid 23 gallon recycling can with a loose fitting lid for months on end and it stays at 0 to 1 and it is not food rated.
TDS directly out of unit is 0 and after filling the bucket it too reads 0. It's only the last half gallon or so that gave me the 002 reading.
The only things that sits in the bucket during the top off stage is the tubing & a small holder for the tubing. The holder came with the JBJ ato unit.
Anyways...I'll give it a good bath as AZ suggests.
Thanks for the replies guys
This happens to me as well if I dont use my water fast enough. The botton bit starts to have a TDS reading. I wouldn't be too alarmed at .002. It is just a basic law of chemistry that things will go from higher concentrations to lower so anything in the air or items the water touches will slowly move into the pure water. This will happen in your tank as well though its not as apparent because tank water is not pure.
The TDS is not in decimals. What appears to be a decimal point on many meters is actually an indicaton the meter is on, they read in whole numbers unless you have a handheld like the COM-100 which is one of the very few that actually reads down to tenths or one decimal point.
002 is 2 TDS.
RO/DI and distilled water are very agressive sine they have had all their ions stripped out and are constantly trying to get back to their natural "dirty" state so will attract dust, volatiles, organics, inorganics or anything they can pull into solution and raise the TDS back up. Keep the RO/DI sealed or at least covered and try to keep buckets. scoops, pumps, hands and everything else out of the storage and it will stay close to 0 TDS.