WMAS Discussion Forum : RO Mystery-Need Help http://www.utahreefs.com/forum/ Copyright (c) 2006-2013 Web Wiz Forums - All Rights Reserved. Mon, 29 Jun 2026 14:41:04 +0000 Thu, 13 Jan 2011 23:07:39 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.03 360 www.utahreefs.com/forum/RSS_post_feed.asp?TID=45905 <![CDATA[WMAS Discussion Forum]]> http://www.utahreefs.com/forum/1by1.gif http://www.utahreefs.com/forum/ <![CDATA[RO Mystery-Need Help : Here is one... it even comes...]]> http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=394373&title=ro-mysteryneed-help#394373 Author: Davidwillis
Subject: 45905
Posted: January 13 2011 at 11:07pm

Here is one... it even comes with the post filter

http://cgi.ebay.com/REVERSE-OSMOSIS-RO-REPLACEMENT-WATER-FILTERS-MEMBRANE-/360334407853?pt=Small_Kitchen_Appliances_US&hash=item53e59ab8ad


Edited by Davidwillis - January 13 2011 at 11:08pm]]> Thu, 13 Jan 2011 23:07:39 +0000 http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=394373&title=ro-mysteryneed-help#394373 <![CDATA[RO Mystery-Need Help : Who sells a 50 GPD membrane and...]]> http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=394368&title=ro-mysteryneed-help#394368 Author: Jeffs_little_ocean
Subject: 45905
Posted: January 13 2011 at 10:44pm

Who sells a 50 GPD membrane and all the prefilters shipped for $50? No I dont have a storage tank, but now that I know that the water in Kaysville has 560 PPM, I might get one lol.]]> Thu, 13 Jan 2011 22:44:03 +0000 http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=394368&title=ro-mysteryneed-help#394368 <![CDATA[RO Mystery-Need Help : You should be able to get your...]]> http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=394310&title=ro-mysteryneed-help#394310 Author: Davidwillis
Subject: 45905
Posted: January 13 2011 at 7:41pm

You should be able to get your membrane and all pre-filters for $50 shipped.
Do you have a storage tank?  
]]> Thu, 13 Jan 2011 19:41:42 +0000 http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=394310&title=ro-mysteryneed-help#394310 <![CDATA[RO Mystery-Need Help : Because I bought my RO unit used...]]> http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=394308&title=ro-mysteryneed-help#394308 Author: Jeffs_little_ocean
Subject: 45905
Posted: January 13 2011 at 7:24pm

Because I bought my RO unit used and am not sure about the age or shape of the membrane, I decided to get my water tested tonight. I took a sample of my tap and a sample of my RO/DI to Aquatic Dreams. The tap was 560 TDS. Ben said that Clearfield water is typically 500-600. To my suprise my filtered water still had a TDS of 260. Yikes! Time for a new membrane I guess. Like Micah, I really regret not just buying a new RO/DI system. I paid $50 for the unit and spent $50 on 3 new filters and Im sure a new membrane will be at least another $50. BRS sells a unit for $160 that has a pressure guage and a 2-stage TDS meter and I should have just done that....oh well]]> Thu, 13 Jan 2011 19:24:14 +0000 http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=394308&title=ro-mysteryneed-help#394308 <![CDATA[RO Mystery-Need Help : LOL... I read post and was thinking...]]> http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393763&title=ro-mysteryneed-help#393763 Author: Davidwillis
Subject: 45905
Posted: January 11 2011 at 10:01am

LOL... I read post and was thinking pre...Embarrassed


]]> Tue, 11 Jan 2011 10:01:13 +0000 http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393763&title=ro-mysteryneed-help#393763 <![CDATA[RO Mystery-Need Help : The key word is &#034;post&#034;....]]> http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393762&title=ro-mysteryneed-help#393762 Author: Mark Peterson
Subject: 45905
Posted: January 11 2011 at 9:51am

The key word is "post". That means after the membrane. As you may know, in the simple yet effective RO unit the water flows like this:
 Tapwater -> Sediment filter -> Activated Carbon filter -> Reverse Osmosis Membrane -> purified water.
                                                                                                       -> waste water.
Like you said, the Carbon PRE filter is useful. I'm not sure it's that much of a necessity because the the type of membrane we use (TFC -Thin Film Composite) but it is helpful and probably prolongs the useful life of the membrane more than the cost of the AC filter cartridge.

The CTA (Cellulose Triacetate) membrane is destroyed by Chlorine so the AC prefilter is an absolute necessity. Don't worry, this type of membrane is usually not sold to ordinary consumers, so there's little chance that you would accidentally get one.


Edited by Mark Peterson - January 11 2011 at 9:59am]]> Tue, 11 Jan 2011 09:51:48 +0000 http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393762&title=ro-mysteryneed-help#393762 <![CDATA[RO Mystery-Need Help : Thanks Mark, very good post. The...]]> http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393757&title=ro-mysteryneed-help#393757 Author: Davidwillis
Subject: 45905
Posted: January 11 2011 at 9:24am

Thanks Mark, very good post.  The only thing I am concerned with is that you don't use a carbon post filter.  As long as there is no chlorine added to the water should be fine.  But on my membrane it says the free chlorine tolerance is <0.1ppm.  My understanding is that the chlorine can ruin the membrane.  I am not sure what the free chlorine level is when they add chlorine to the drinking water.  Maybe it is less than that and nothing to worry about?  I would like to hear why you don't use the carbon filter.]]> Tue, 11 Jan 2011 09:24:11 +0000 http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393757&title=ro-mysteryneed-help#393757 <![CDATA[RO Mystery-Need Help : Tresa, I agree with David...]]> http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393749&title=ro-mysteryneed-help#393749 Author: Mark Peterson
Subject: 45905
Posted: January 11 2011 at 8:44am

Tresa, I agree with David about changing the prefilters every six months but it all depends on the amount of use. I have had the same prefilters for almost a year and they are still good because my wife and I have needed only about 15 gals/week out of our RO unit. (This is an ordinary 3-stage unit we bought from Dana Riddle when we were living on the Big IslandBig smile) It doesn't have a carbon post filter and never has needed it. Smile

The rule of thumb is to look at changing the membrane when TDS starts to climb fast. If the TDS has always been 0-10 ppm, when it starts climbing and gets to 30 is when I would suggest changing the membrane. If the membrane typically delivers 20 ppm water, change it when the ppm has risen to 50 ppm.

Many LFS, being concerned with cost vs. value, allow their purified water to be almost 100 ppm before changing the membrane, too often that action is a response to some hobbyist's complaint. Smile

The Membrane is an extremely fine mesh made of durable plastic which lasts for many years. It does not typically spring a big leak and start allowing a lot of tap water through. Over time, as it deteriorates it springs very tiny leaks. More and more impure water will seep through so that over the course of 2-6 months the Total Dissolved Solid materials may double or triple. As a point of interest, a membrane that has been allowed to sit unused for 6 months to a year will develop a bacterial growth which clogs the fine mesh holes and renders the membrane useless, so it's not good to let an RO unit sit idle for too long.

Remember that many hobbyists use tap water with success, especially in areas where natural TDS is around 180-300. Of course their tanks have developed a natural growth of algae, bacteria and invertebrates including coral that eat the "impurities". Remember this, among the "impurities" at the top of the list in tap water are Alkalinity, Calcium, and Magnesium. So tap water actually has a lot of what we feed our tanks. This means that the less pure water coming out of a deteriorating membrane is actually good for our tanks for a little while.

I and several experienced hobbyists here actually top off with tap water from time to time to replace the trace elements that our tanks have used. The minerals naturally occurring in ground water are what is fed to the ocean by the rivers of the world. Use of a small percentage of tap water is simply mimicking the natural environment. The reason I/we do this is because not all trace elements may be fully provided in salt mixes and supplements.

Also remember that salt water has a TDS of ~35,000 ppmShocked yet we want that kind of impure water, right! Wink

I hope this makes sense.


Edited by Mark Peterson - January 11 2011 at 9:00am]]> Tue, 11 Jan 2011 08:44:47 +0000 http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393749&title=ro-mysteryneed-help#393749 <![CDATA[RO Mystery-Need Help : You want to change your pre-filters...]]> http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393710&title=ro-mysteryneed-help#393710 Author: Davidwillis
Subject: 45905
Posted: January 10 2011 at 8:52pm

You want to change your pre-filters regularly, especially if you have chlorine in your water.  Chlorine will eat up the filter, but the charcoal pre-filters take it out.  I change mine every 6 months even though I don't have any chlorine.  If you have a TDS meter just keep an eye on it, and if it starts to go up then change it.  There is no set TDS level.  I know mine has stayed at about 6-10 for a long time, but I just noticed that it is at 11-12 so I just ordered a new membrane (my old one is 4-5 years old).  Or you can just change the membrane every 2 years and probably be safe.  I also change my post carbon filter every year, or if the water starts to tast funny.]]> Mon, 10 Jan 2011 20:52:44 +0000 http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393710&title=ro-mysteryneed-help#393710 <![CDATA[RO Mystery-Need Help : Sorry to get somewhat off subject...]]> http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393694&title=ro-mysteryneed-help#393694 Author: Tresa
Subject: 45905
Posted: January 10 2011 at 7:18pm

Sorry to get somewhat off subject but what should I let my TDS reading get too before I worry about changing the R/O filters?]]> Mon, 10 Jan 2011 19:18:18 +0000 http://www.utahreefs.com/forum/forum_posts.asp?TID=45905&PID=393694&title=ro-mysteryneed-help#393694