RO/DI water preparation and storage

[SRWoodcock]

I am just thinking about how to top off my tank. I have a 90GPD 5 stage RO/DI for a 120G tank with 50 Gal sump. I thought I would use an ATO device to manage the top off function by checking the level in my sump and then adding RO/DI to compensate for evaporation losses.

The questions become:
1. What can I store the RO/DI water in? Are there any particular container materials to avoid?

2. Do I need to do anything to the RO/DI water while it is stored or before it is delivered to the tank?

I have heard that DI water will suck impurities out of the air, ( not sure if this is true) that DI water sould be aeriated ( this idea conflicts with the first idea) and that DI water should be heated.

 

[reefreefer]

I would use a food grade container, I would also try to keep it circulating. I leave my top off water in 5g water containers and It has sat for almost 2 weeks at one point with no visible changes when I tested the results were as clean as the fresh R.O.
I guess that there are buffers for R.O water but I have never found them necessary as long as you are using good salt and monitoring your trace elements. I do like to dose Kalkwasser but it is not necessary

 

[reefreefer]

you could compare the P.H and maybe buffer the RODI closer to it, how long are you going in between top offs? If you do add anything make sure you monitor it.

 

[roblou]

I have not heard that DI water should be aerated while it's being stored. I definitely think that could/would cause the DI water to absorb some TDS (i.e. dust/smoke/etc in the air would end up in the water).

I don't keep mine heated either. I use empty 5g salt buckets to hold RO/DI water for top off, which are hooked up to an ATO that uses a aqua lifter pump to move the RO/DI from bucket to sump.

HTH,

Rob

 

[NWDiver]

I store RO/DI in a covered food grade plastic 55gal. barrel with an ato to keep it full, and I have a 10 gal. covered rubbermaid that has an ato to the sump to replace the evaporated water. I do not mix or add air to either. I do test tds every so often to see that all is well. It has not been a problem so far.
People who add RO direct to the sump from a large container or the RO unit are either braver than I or they have a floor drain...

 

[SRWoodcock]

Thanks guys

 

[dragoneggs]

People who add RO direct to the sump from a large container or the RO unit are either braver than I or they have a floor drain...

Are you implying a failure of the float switch to shut off ATO? I have two... one at the top of my 65gal RO/DI storage tank and another in my sump. I suppose if one of them got stuck in the 'down' position a flood would happen. That would be bad.

I don't worry about it so much in my storage tank as the water is fresh. In the sump it is subject to salt creep and stick.

 

[NWDiver]

You are right on the money, the storage tank is probably much less likely to fail a float, but what happens if the one in your sump fails? If you have the 65 going direct to the sump and the sump switch fails (and it will eventually) then you have 65 gallons of fresh added to the sump (and the floor) plus it will continue to make water (unless it is on a timer) until you shut it off.
A pair of sump switches in the sump is good, a smaller container between the storage and the sump that gives you a limited amount of fresh that can auto-add is good-er.
It does add another thing to check every few days, but it is worth the peace of mind to me.

 

[mcoomer]

I have an ATO on my sump that runs from the 60gpd Spectrapure that I have in the garage. When the sensor sees a low water level it turns on a solenoid that allows water to flow to the RO/DI unit. On the output of the RO/DI is a tee. One leg of the tee runs to a Rubbermaid Brute with a float valve inside to cutoff the water when it's full. That's the water that I use for maintenance. The other leg of the tee runs under the house and comes up behind my tank and into the sump. There is a float valve in the sump as well. I've run this setup for probably 10 years now with no problem

 

[SRWoodcock]

Mike,

That is just about the same as what I have in mind. I thought i'd use a brute for a mixing tank in my garage, and then another brute for RO/DI top off storage. I also picked up a couple of 24VDC lawn sprinkler valves that I will put in series before my Spectrapure. I'll use two float switchs ( high and low ) in the storage brute to activate the RO/DI unit.