Ro/di Water Lifespan?

[jackwhiteiii]

Hi guy's

At the moment I am getting my water from my LFS, but its a bit of a mission to get it so I am wanting to get it in bulk so I don't have to make the trip so often.

My question is how long can RO water be kept before it is unusable, I will be keeping it in 4 gallon plastic cannistors with lids.

Also I am looking into a R/O unit myself and have noticed that they all claim to have various stages of filteration rangeing from 3 stage to 6 stage. Now cost is an issue and have found a 3 stage unit for £35, will this be good enough? or should I spend more and get a 4,5,or 6 stage unit?

Thanks

III

 

[idlefingers]

I don't see how it could "go off" at all, so surely it'll last for ages?

With the Ro units, the more stages, the more filtered the water gets (and I think sometimes less waste). I have a 4-stage unit (sediment filter, carbon filter, membrane, de-ioniser) and it gives me Ro with 0ppm TDS so I'm happy with that. A 3-stage unit doesn't have a de-ioniser stage so you'll probably end up with water of about 10-20ppm TDS (or at least this is what I've read). I guess it depends on how much this matters to you as to whether the DI stage is needed..

 

[xxBarneyxx]

I asked the same question and was told that the RO water will keep for quite a long time. With regards to a 3 stage unit I have read that adding a DI unit is not a must have.

 

[SkiFletch]

I asked the same question and was told that the RO water will keep for quite a long time. With regards to a 3 stage unit I have read that adding a DI unit is not a must have.

Correct. RO water will last for months, if not years if stored in a suitable container and covered to prevent dust from getting in it. Try to use food-grade plastic containers to store it longterm.

DI units are rarely necessary. If you're trying to accomplish some high-tech acropora garden, then I'd probably suggest using it to be safe, but for the vast majority of aquarists, DI is not useful (I have one but never re-fill the resin )

 

[Musho3210]

the better the RO membrane, the cleaner the water. It may be 10-20 tds, or 0-10 tds. But a 75 gpd membrane cleans better than a 100 gpd membrane.

 

[AK77]

The only possible problem I could see is storing the water longterm in unclean or unsuitable containers that are not air tight or allow material to get into the water. Since there is no chlorine or other antibacterial agents in the water, pretty much any bacteria could breed unabated in the water. Although many RO units sterilize the water by removing bacteria and viruses, if the containers aren't clean you could possibly run into problems of this nature.

I use 25L food grade Jerricans to store the water and never have a problem, although I do run a UV sterilizer in my sump.

 

[jackwhiteiii]

Thanks for the advise guys, defo gonna get a ro unit and will look around for a 3 or 4 stage filter I think, do they all have to be plumbed in or can you get ones that just fit to the tap? I've only got an 8 gallon nano so dont need a super high output one!