R/O water storage & TDS
 

I keep R/O water stored in a 30 gal Rubbermaid container. This water is used for salt mixing, topping off sump, etc. I currently have 3 tanks set up: a 90 gal + 54 gal sump, 70gal, and a 20 gal. Between water changes, top off, etc. I go through this 30 gal container in 6-7 days, then fill 'er up again. Today I checked TDS in the container with the meter and it read 121ppm!! (I figured the R/O unit was not working, so I made up some R/O water and tested it: it read 1.0ppm (unit works fine). I then tested our tap water which read 12ppm. How is it possible for TDS to rise that high in 1 week? The storage container is rinsed out every week when I empty it so it is not a build-up of crud on the bottom. Any thoughts?

Do you fill it up immediately or let it dry out? Leaving water in a bucket for 6-7 days sometimes causes a biofilm to build up on the sides of the bucket. Try wiping that out with a paper towel and then let it dry completely before filling it back up again. That might help.

I was gonna check the TDS in my reservoir bucket but my the batteries in my TDS are dead. I think I've checked my ATO reservoir and the TDS was definitely higher than the 1.0 that comes out of my RODI. About 25 or so.

Ahhh... the headaches I can look forward to when I switch to RO.. :lol:

[quote=christyf5;340592]Do you fill it up immediately or let it dry out? Leaving water in a bucket for 6-7 days sometimes causes a biofilm to build up on the sides of the bucket. Try wiping that out with a paper towel and then let it dry completely before filling it back up again. That might help.


No, I haven't been wiping down the sides, I just rinse the container out well and refill it. I'll try the wiping and drying and see if that helps. Thanks

remember reading on RC the same question awhile back. This isn't the thread I was looking for but similiar.

Either way sounds common to get a rise after storage.

Interesting. Kinda makes you wonder sometimes why we even bother buying a R/O unit. Heck, my tap water is 12ppm which is not bad considering the R/O water's TDS is only going to rise anyway. Huh!

I think the best benefit of the RO is to remove unwanted minerals and chemicals like chlorine, flouride and COPPER. If you put clean water IN and TDS rises slightly(remember this is ppm) when stored it is probably a benign bacteria growth eating something left behind from a water change. If the rubber maid plastic is soft, it is probably scratched and that is where the bacteria are finding their nutrients. The amount is SO small that they soon starve out and what you are detecting is their dead cells or whatever. Unless the TDS is REALLY high or the water has an "organic" smell(Phew!) I would not be concerned. T

This is just one theory for the mysterious rise in TDS with stored water.

Snaz.

Maybe the bin is leaching something into the water.

X2 you are probably better off with a food grade bucket try the wine store they sell food grade buckets.

Im going to go look for a food-safe container today or tomorrow: I was never really happy with the Rubbermaid anyway. The plastic is too thin and flimsy.