Warning for RO-only users

[Slick Fork]

I've read before that RO systems really don't like the on/off cycle and do much better if you can do larger batches at atime rather then a litre here and a litre there.

I fill my top off container once every week and a half. A little more labour intensive, but I feel it's better for the RO membrane and better for my piece of mind as there's only a finite supply of water that could go into my tank if there's a malfunction.

[dino]

i think big batches is a better way to go also i just use my float as a back up if i forget to turn it off

[gregzz4]

Just to clarify ...

I don't leave the system running
When the drum gets low I purge the TDS creep, fill the drum, turn off the inline valve to keep the membrane pressurized, and then turn off the water supply

[Zoaelite]

A few weeks ago I tested my HT water and found it to be a crazy 6PPM
That's nearly my City Water value

My advice is to sit back and not worry about it.

Calgary water standard is between 156- 299ppm, I don't believe we are getting anything close to zero out of our units. As people have run successful tanks with Calgary water I don't think 6ppm of TDS is going to hurt you at all.

[kien]

Originally Posted by Zoaelite

My advice is to sit back and not worry about it.

Calgary water standard is between 156- 299ppm, I don't believe we are getting anything close to zero out of our units. As people have run successful tanks with Calgary water I don't think 6ppm of TDS is going to hurt you at all.

I didn't want to be the guy to say it but ya, freaking out at 3-5ppm TDS ?? You West Coasters are spoil by youre clean water! LOL. I don't panic until my RO reads 10tds at the exit. I try to replace filters sooner but sometimes I get busy (lazy) and don't notice until around 10 tds.

[daniella3d]

same thing here. I only replace my membrane when it is at 10 or 12 tds.

Never has a problem.

Originally Posted by kien

I didn't want to be the guy to say it but ya, freaking out at 3-5ppm TDS ?? You West Coasters are spoil by youre clean water! LOL. I don't panic until my RO reads 10tds at the exit. I try to replace filters sooner but sometimes I get busy (lazy) and don't notice until around 10 tds.

[mike31154]

I tried using the auto shut off on my system when I first set it up. Could never get the waste water to stop running even after the float valve had closed for some time. I played around with the auto shut off valve a bit, even disassembling it, but still could not get it to work as advertised with any sort of confidence in it's reliability. I've been manually turning the water on/off now for years when I make water. This way I can flush at start up & again when I shut down. I use a timer to remind me to check the storage container. Had the odd minor flood due to inattention, but nothing major. I now have a battery powered water detector on the floor that alerts me if I forget about the timer. It beeps very loudly!

As others have mentioned, with your low incoming TDS on the coast, you folks are very fortunate. My source water is usually over 200 TDS. Only time it's lower is when they change the source from Kal Lake to Duteau Creek, which is not very often. Duteau Creek source is generally in the 30's for TDS.

I recently added a second Dual TDS meter to my system so I can monitor source water TDS before & after the pre filters as well as before the RO membrane & the DI output. I was quite suprised to find that during the first 5 or so minutes of running the system, the TDS after the pre filters (5 micron sediment, 1 micron sediment & 0.5 micron carbon block) reads noticeably higher than the incoming source water. My theory on this is that while the system is sitting idle for days, possibly even a week, the sediment & solids that are trapped in the pre filters actually dissolve in the stagnant water resulting in higher TDS downstream once the system is started up again. After 5 minutes or so, the TDS after the pre filters levels out at a few points below the source water TDS.

No wonder folks with overly automated RO systems that turn on/off in short cycles generally end up with higher TDS water at the output, along with increased wear & tear on system components. I'm still using the original 75 gpd membrane (over 5 years now) & manage to get 1 TDS after RO with over 200 TDS source water. I like to think this is because of my routine of manually turning water on, flushing for 2-3 minutes before switching the restrictor on, dumping the first half gallon or so of RO water and flushing again when I manually shut the system down. And before running anything through the DI media, I always make about 5 gallons of RO only for drinking water, pop, beer & wine making. This ensures the RO output is as low as it's going to get before I switch the DI into the loop. My first batch of DI media lasted about 4 - 5 years this way.

[Seriak]

But thank you for the explanation as it now tells me why my RO water is testing higher in my containers.

[kien]

Originally Posted by Seriak

But thank you for the explanation as it now tells me why my RO water is testing higher in my containers.

tru dat! I did wonder about that actually.. now we know!

[lastlight]

Really interesting on the float valve creep that's a new one to me. I just set a timer on my phone and manually shut things off (after a back flush) so I guess I'm not experiencing this fancy new creep.