R/O Water Storage Question

spawn · #1 12-22-2010, 02:06 AM

When I make up my water I use 5 gal pails. 1 is a full time reservoir that never moves. The other 3 I use for mixing and water changes. When I'm finished a change I wash out & dry the pails thoroughly.
It seems that if I store water in these pails though for the course of the week there is is rise in the TDS from 000 up to 2-5, so I don't use it, so the question is :
Is this minimal rise in TDS because I must have missed a spot & if so is this water still safe to use because the rise would be due to some residual salt mix? I don't feel like wasting any more water.

mike31154 · #2 12-22-2010, 02:33 AM

I use a rectangular rubbermaid type container to store & mix my fresh water, about 25 gals I think it holds. I just rinse it a little and let air dry between use. Have never checked the TDS of the RODI in there since I generally make it up a few days before water change and mix in the salt fairly quickly after production. There's quite a bit of calcium/mineral build up on the inside of the container after a few years of use, so I'm sure the TDS rises as soon as the RODI water hits it. I certainly wouldn't sweat a slight rise in TDS and definitely wouldn't discard it because of that. I used treated tap water for the first couple years of running my system, so a bit of TDS after RODI production is not going to get me too wound up. Do you have lids for your pails? That might keep the TDS down closer to 0 for you.

spawn · #3 12-22-2010, 02:38 AM

Yep there's lids on them whether there's water in them or if they're clean & dry. Also I forgot to mention that the water in the bucket I use for the reservoir has always had TDS of 000. & I do realize that I tend to over think most things.

mike31154 · #4 12-22-2010, 04:34 PM

No worries, I have read other folks post that due to the very pure nature of RODI water, it has a tendency to be very aggressive in trying to absorb any kind of material it comes into contact with, including air, causing the TDS to naturally rise over a period of time. I'm just repeating info I have read in that regard, so no scientific evidence to back it up, but it does seem to make sense.

spawn · #5 12-22-2010, 09:34 PM

Thanks man, I've actually heard that before as well. Happy holidays.

Myka · #6 12-24-2010, 06:51 PM

What kind of buckets are these? I'm assuming they are old salt buckets, but maybe they aren't? I use a couple of food safe 65 gallon barrels for my water, and even after a month the water still has 0ppm TDS. I don't even use lids on them, just drape towels over them to keep dust out. I over-think everything too, and I'm super anal about things like RO/DI water, so in my case I would find your current situation unacceptable for fear of what exactly is that 5-10ppm anyway?? For the average reefer, probably not an issue.

spawn · #7 12-28-2010, 04:40 PM

Does that mean that the water is safe to use? Kinda like I already kinda determined I was going to do?

Phoenix_M · #8 12-28-2010, 04:49 PM

yeah i'd say it's fair to use; UNLESS of course there's something leaching out of some contaminated plastic that you might be aware of.

we run a lab here and have a water polisher going 24/7..our water NEVER gets to absolutely "0" TDS due to c02 in atmosphere. it's nearly impossible.

guess a summary is; this is natural for very pure RO as Mike said.