got a ro/di unit today

Re: got a ro/di unit today

<a href=showthread.php?s=&postid=14706609#post14706609 target=_blank>Originally posted</a> by bigmatt1992
got a 4 stage ro/di unit off of vr697getta today the tds reades 2. new filters to come in a week or so.

Maybe you just need a DI recharge and not new filters? What is your TDS right out of the tap and then again right out of the RO membrane (before the DI)?

--Ray
 
my tap is 175 ish it goes up and down with wether i dont know why. 175 is the avg. thrue everything its 2 tds idk how to tst it right oafter the ro membrane.
 
<a href=showthread.php?s=&postid=14707605#post14707605 target=_blank>Originally posted</a> by bigmatt1992
my tap is 175 ish it goes up and down with wether i dont know why. 175 is the avg. thrue everything its 2 tds idk how to tst it right oafter the ro membrane.

You can disconnect the line running into the DI and test it.

Really, that is pretty good though.

What all did you order for filters (Prefilter, carbon block, RO Membrane)?
 
didnt order yet but im thinking about a package deal for all filters from bulk reef for 75, i think it was . that include everyfilter including DI. but i wont use it till my tds is about 4 that way i know the filters on it now are done for.
 
<a href=showthread.php?s=&postid=14707703#post14707703 target=_blank>Originally posted</a> by bigmatt1992
didnt order yet but im thinking about a package deal for all filters from bulk reef for 75, i think it was . that include everyfilter including DI. but i wont use it till my tds is about 4 that way i know the filters on it now are done for.

I would test the output after the RO membrane first before ordering anything. You may not need it. You may just need the two prefilters and some DI resin.

Do you know how old the RO membrane is?
 
<a href=showthread.php?s=&postid=14707768#post14707768 target=_blank>Originally posted</a> by bigmatt1992
roland said everything is due for a change soon. so im not sure.

Ok, well you can change it to be sure, but if you can test the output after the RO membrane we can know for sure if it is still good or not.
 
all the filters are about 6 months old. you should get a year out of a ro membrane. so it has 6 months left. you can wait untill the next time you order filters to pick up the membrane.
 
Ok, so if the filters are 6 months old you will want to change out the pre filters now. I would wait on the membrane then.
 
A good rule of thumb is to replace your sediment filter and carbon block after six months. A more precise way to maximize the useable life of these two filters is to use a pressure gauge to identify when pressure reaching the membrane starts to decline. This is your indication one or both of the filters is beginning to clog.

Also be cognizant of the chlorine capacity of the carbon block. The Matrikx+1 (“Chlorine Guzzler”) for example will remove 99% of chlorine from 20,000 gallons of tap water presented at 1 gpm. Original equipment suppliers commonly provide carbon cartridges rated at 2,000 to 6,000 gallons.

Regarding your RO membrane and DI resin, use your TDS meter to measure, record, and track the TDS (expressed in parts per million) in three places:
1. Tap water
2. After the RO but before the DI
3. After the DI.

The TDS in your tap water will likely range from about 50 ppm to upwards of 1000 parts per million (ppm). Common readings are 100 to 400 ppm. So for sake of discussion, let's say your tap water reads 400 ppm. That means that for every million parts of water, you have 400 parts of dissolved solids. How do we go about getting that TDS reading down to somewhere near zero?

If you do some experimenting with your TDS meter, you'll note that your sediment filter and carbon block filter (collectively called “prefilters”) do very little to remove dissolved solids. So with your tap water at 400 ppm, you can measure the water at the “in” port on your RO housing and you'll see it is still approximately 400 ppm.

The RO membrane is really the workhorse of the system. It removes most of the TDS, some membranes to a greater extent than others. For instance, 100 gpd Filmtec membranes have a rejection rate of 90% (i.e., they reject 90% of the dissolved solids in feed water). So the purified water coming from your 100 gpd membrane would be about 40 ppm (a 90% reduction). Filmtec 75 gpd (and below) membranes produce less purified water (aka “permeate”), but have a higher rejection rate (96 to 98%). The life span of a RO membrane is dependant upon how much water you run through it, and how dirty the water is. Membranes can function well for a year, two years, or more. To test the membrane, measure the total dissolved solids (TDS) in the water coming in to the membrane, and in the purified water (permeate) produced by the membrane. Compare that to the membrane’s advertised rejection rate, and to the same reading you recorded when the membrane was new. Membranes also commonly produce less water as their function declines.

After the RO membrane, water will flow to your DI housing. DI resin in good condition will reduce the 40 ppm water down to 0 or 1 ppm. When the DI output starts creeping up from 0 or 1 ppm to 3 ppm, 5 ppm, and higher, you know that your resin needs to be replaced. Sometimes people complain that their DI resin didn't last very long. Often the culprit is a malfunctioning RO membrane sending the DI resin “dirty” water. This will exhaust the resin quicker then would otherwise have been the case. Sometimes the problem is poor quality resin â€"œ remember that all resins are not created equal!

IF you are going to change out the filters now would be a good time to sanitize the system as well.

Russ
 
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