Ideal temp for making r/o water

The girlfriend is getting mad that I took over the basement bathroom w/ all my fish tank gear (r/o unit). So I am thinking I am going to move it to the laundry room where I have a few exposed pipes. Plan is to T off of a hot and cold water pipe to a mixing valve then to a ball valve then to my r/o unit. My question is, what is the best temp to set the mixing valve to in order to make the water? Right now I have it hooked up to my sink in the bathroom and I feel like warm water makes the most water but I really don't know what temp that is. I believe I can set an exact temp on the mixing valve.

 

I just make mine cold and put a heater in my container. Never heard of anyone mixing it warm

 

My unit said only use cold water I believe. Of course here in Fla we don't actually have cold water like most states do. But I'm sure it's referring to not use hot water. But I like the idea of being able to adjust the temp a lil.

 

Cold water contracts the membrane better and to work better.

 

do not use hot water. only connect the cold h20 to your RODI unit. hot water can damage your resins.

 

Thank you for the quick responses! What do you guys consider cold though? Is there such thing as too cold? The temp during the winter out of the faucet in Vermont is probably only in the high 40's-low 50's. Knowing this would you still just hook up to the cold line or do mixing valve and shoot for a temp in the 60's???

 

After a quick search I found that manufactures test gpd at 77*. But I also seen that the cold water runs slower but it actually filters better. So warm water through ro/di is not as good as cold water. Ive read that you can buy a device to add water pressure to your system. I think that would be the best thing to do so you get faster water.

 

I added a booster pump to my system. It is a 100 gpd unit but before the booster was only getting around 40 gpd. Now im getting 80 - 90.

 

You could make the RO/DI cold, let it sit for a day at room temp, for me, that's 69F, them mix salt and warm with a heater.

Here in WI, I usually make the RO/DI at night, then heat while I'm mixing, get it close on temp, and pump it into my sump. Usually about 20g in whats probably a 140 total system.

Agreed, don't make it with any hot line water.

 

+1; water temperature through the membrane is a trade off. Warmer water will give you higher flow, but at a cost of more dissolved minerals passing through it. This means your DI resin has to work harder and won't last as long. Cold water (40 deg is fine) will give you better rejection (aka your resin lasts longer), but at a cost of lower flow (can be significantly lower).

So, if you have an auto shutoff for your RODI and can set it and forget it, you're probably better off going with cold water. If you don't and you need to make the water quickly, go with warmer water (I wouldn't go above 75-80 deg). Both cases will give you 0 TDS water assuming you have a DI cartridge. One setup is more time and the other is higher resin cost.

A booster pump is also an option if you want higher flow with colder water.