Your RO or RO/DI unit...did you know?

[Myka]

I know lots of people know, but many don't, and I'm bored waiting for a download right now, so...

*drum roll*

When you first turn your RO or RO/DI unit on it spits out a higher TDS for the first litre or so of water. Mine spits out 8 ppm if I collect the very first cup of water that comes out of there, and slowly goes down to 0 ppm after about 1 litre of water has passed through. So I let my unit run for a couple minutes before collecting the water.

Also, check out your tap water's TDS. My cold water runs about 92 ppm, and my hot water runs about 102 ppm. So, even though your unit will run much faster if you use luke-warm water, you will often be pushing through water of a higher TDS, so you're using up your RO membrane quicker.

Ya, so there's my nerdy thought of the day.

Cheers!

[Alberta-newb]

Learn something new everday! Thanks for the info, I just ordered in a RO/DI so now I'll make plans to install a valve ahead of my reserve so I can flush away that first litre or two. Since I'm installing my unit right beside my tank, I was thinking of geting an extra 25' of tubing, coiling it up and putting it in the sump to pre-warm it a little (my supply is quite cold) Think this is a good idea?

Francis

[mark]

thread here about warming ro supply.

And cutting/paraphasing from Aqua-safe: "membranes are flow rated at 77F, 65 PSI and 200 TDS and for every 1F water temperature (below 77F), the production rate will drop 1.6%

[Myka]

^ Yep, that just means the flow will slow, it doesn't mean it damages the RO membrane.

Example...my 50 gph unit takes about 2 1/2 hours to fill a 5g jug if I use straight cold water. If I use luke-warm water (prob around 75-80 degrees) it only takes about 1 1/2 hours to fill. BUT, I'm introducing a higher TDS to my RO membrane if I use warm water, so I'll save the RO membrane, and deal with the slow water flow.

[atcguy]

I was told thats units shouldnt be run all the time. They need to stay running for 15 minutes or more ... ie to keep a resevoir filled by a float valve.. So now my controller tells me every 4 days to run my ro unit and top my resevoir up. Doing this allows the unit to run for 2 hrs to fill my container opposed to on off on off throughout the day.. Works for me