RO / DI Unit changes?

WilyGuy · 01-05-2006, 11:54 AM

I know enough about my RO /DI unit to fill the next word...." "

I installed it this summer. Should I be keeping track of the amount of water I make? What needs to be replaced and how often? (based on water or time?)

How frequently should I "flush" it? I have a valve that I can flush it, I think.

Thanks.
WG

tainte97 · 01-05-2006, 02:36 PM

I hooked one up this summer to and I have no idea. Sure someone will let us know.

drsyme · 01-05-2006, 02:46 PM

Get a TDS meter.

WilyGuy · 01-05-2006, 03:00 PM

Got one of those with it. What do I do with it?

bchnit1 · 01-05-2006, 03:09 PM

I bought one with a handy dandy little light that goes on when it needs a new membrane. Hadn't replaced it yet since water was still flowing but the light turned red about 2 months ago- can you say hair algae???

Yeah I'm real bright...the algae started gorwing moderatly about 2 weeks ago so I have the membrane on order- none in stock when you need them, go figure. Gonna need more snails if doesn't get here soon!!

From now on I'll react alot quicker to a red light.

tdwyatt · 01-05-2006, 03:13 PM

Best: buy one of the inline TDS units and install it in the finished-water line to measure TDS of your filtrate. My personal goal is to never use water at > 0.01, but I have friends in the hobby that will go as high as 0.05

. There are some newer inline units that measure your TDS in both the incoming water and the filtrate, useful in evaluating the fluctuations in mains water. I have seen some folks place the two probe units such that they can monitor the quality of the water coming from the RO membrane as well as the finished product to monitor the useful life of the RO membrane, but if you keep the membrane flushed after each use, and do not expose it to chlorine, particulates, or extremely hot water, most high quality membranes will last for many years, it all will come down to good maintenance and upkeep of the total filtration unit.

Good: use a portable "pen"-type of TDS meter to test your filtrate as or after it is made. Testing in a barrel will sometime give a false high reading if the water is supporting some slime growth in the barrel, also an indication that it is time to scrub out the empty barrel with baking soda powder (NEVER USE SOAP!) and rinse the barrel until totally clean, then allow to air dry, preferably in the sun.

OK: So you don't have a TDS meter (very bad)... When you can see any sign of collected dirt on the particulate filter, or every 6 months, whichever comes first, change the filters. Also, many mixed-bed DI resin cartridges have a "color change" indicator in the resin, when more than 3/4th of the resin has changed, it is definitely time to think about reordering new cartridges (or changing the resin at least)

If you live in an area where the TDS of the mains water is very high (Northeastern US, Texas, much of SoCal, etc.), it is in your best interest to backflush the membrane after each filtration session, as it will prolong the useful lifespan of the membrane by removing very fine particulates (< 0.5 microns) and larger macromolecules from the exterior surface of the membrane.

HTH

WilyGuy · 01-05-2006, 03:15 PM

Ah, no light for mine.

What is the time frame or water amount that your light came on?
I make about 6.5-7 gallons in a cartboy every week or so. I typically make water when its raining, since my waste goes out the sump pump to the yard. (Why make the grass wet when it isn't already). Probably been at it since August? so 5x4x7 is 140 gallons? I know that is probably not close to a new filter, but need to know when it will be...

drsyme · 01-05-2006, 03:34 PM

Hey Tom!

As usual, Tom said it all, I have nothing to add to that.

drsyme · 01-05-2006, 03:40 PM

I did find this link:

http://www.reefkeeping.com/issues/20...ture/index.php

tdwyatt · 01-05-2006, 03:41 PM

Good to see you again, Jack! are you taking a vacation, or is the practice falling into that first-of-the-year lull?

BTW, How is the tank doing?

drsyme · 01-05-2006, 03:45 PM

Well...

The practice is busier than ever.

I took a break from the tank sort of, during the summer and fall.

Just didnt have time to care for it that much. (Maybe the sixth child had something to do with that.) But everything is hanging in there, i just have a little majano problem now.

But I am spending more time here now and with the tank, getting everything in better shape.

Oh I got a D50 for christmas, I can send you pics now!

reef_noob · 01-05-2006, 03:54 PM

I got a dual inline tds meter. I put the first meter immediately after the ro filter, the seond after the DI filter. That way, I can measure both the performance of the RO and DI filters. I find that the ro filter needs to be flushed every couple of weeks. Normally my ro unit produces water with a tds >15, and the di polishes it to 0 tds, but when the ro unit needs to be flushed, the ro produces water with 50+ ppm tds. A short, 5 minute back flush returns it back to normal.

tdwyatt · 01-05-2006, 05:42 PM

Quote:

Originally Posted by drsyme

Oh I got a D50 for Christmas, I can send you pics now!

you lucky dog...

I am looking at both the D50 and the D70s, I thought Santa was going to bring me one, but it was a no-show...

Then again, my birthday is just a few months way!

Funny how this thought process seems to pervade the toy-acquisition process even after leaving adolescence...

Good to see you back on TRT again!