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Discussion Starter · #1 ·
I have an RO water question. I have been using my home drinking water RO filter from GE. It doesnt put out lot of water, I know, But I dont need that much right now since Im only running a small Nano tank. Id rather not have to spend the money on a new RO/DI system if I dont have to. We have been using this one for the house and it works well.

http://products.geappliances.com/ApplProducts/Dispatcher?REQUEST=SpecPage&Sku=GXRM10RBL

On Japonicus's suggestion I just got a TDS meter. Even though I have gotten along without one for a long time I figured I would start paying better attention to my fresh water. My system is putting out 16ppm TDS.

My question is do you think I can get away with adding a DI cell to get my water down to 0ppm TDS? The 1st/2nd stage filters and RO membrane are only a few months old and the I can get a DI cell for pretty cheap.

I know ill need to look into plumbing it properly but can I get rid of 16ppm by adding the DI? Or would I still end up above 0ppm TDS

Also is there any special way to clean or store this hannah checker TDS1? There is very little info available that I can find.
 

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It looks like it has a 3/8 output rather than 1/4" most DI stages will feed off of. I suppose you could use a tee before the RO tank but would not have auto shutoff with an open line :(
 

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Discussion Starter · #3 ·
It looks like it has a 3/8 output rather than 1/4" most DI stages will feed off of. I suppose you could use a tee before the RO tank but would not have auto shutoff with an open line :(
I can always use a reducer to get it down to 1/4" right? I mainly want to know if a DI dell will polish off the last 16ppm of TDS I have.
 

· Hydro-Dynamic
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Yes
and
No

Yes you can drop 16ppm TDS to 0ppm with a single DI add on.
Is it cost effective over the life of the membrane?...well without splitting hairs
I would blindly guess you're going to go through DI resin 8x faster than a
membrane that's yielding 2ppm prior to the resin, so if you're using a good
lasting effective resin, that gets expensive. If you're using a "intro grade"
not only are you going to spend your money faster on resin replacement
but removal and replacement.

I'd go with the add on for now and upgrade the membrane with a matched
flow restrictor upgrading the current system you have. Also, if you use
.5µ sediment and carbon filters, your membrane will last longer.
A maximum of 1.0µ should be used, but will let twice as much sediment through. This should rebuild your current GE to a lot better specs for a little less
money than buying an entire new system.

No, there's no special way to cleanse and store your meter.
Just allow to air dry before capping it, then swirl in test sample next time you
use it to rinse the probes of any dust particles.
 

· Hydro-Dynamic
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http://products.geappliances.com/ApplProducts/Dispatcher?REQUEST=SpecPage&Sku=GXRM10RBL
it does have 1/4" inlet and 3/8" outlet
There's no benefit to reducing it other than matching your DI add on
if necessary.

Here's a couple things I'd go with to rebuild yours...
http://spectrapure.com/FILTERS-MEMB...tandard-0.5-Micron-Pre-Filter-Replacement-Kit

http://spectrapure.com/FILTERS-MEMB...-SpectraSelect-Plus-Tested-90-GPD-RO-Membrane
^ 99% rejection rate will save you money

http://spectrapure.com/RO-RODI/ADD-ONS/MaxCap-D1-Single-Stage-DI-System-Add-On-OPEN-BOX
^ Add-on, if you get one for less, the resin within will be a good replacement

Of course this all adds up, so if you just did an add-on, expect to replace
your resin 8x or more faster. Now do that math to be fair now.
How much money will that add up to in 2 years?
Your DI resin just might last 2 years with your stated minimal use.

Another option is just the add on, until your 900g cartridge life has been exhausted
based on your GE link specs (6 months or 900g) and this includes the
full ratio of waste water, not the product of the RO unless its referring
to the membrane. I guarantee your rebuilt unit will need nothing other than
perhaps sediment replaced each year with this minimal use stated.
That's based on sediment from line work which varies drastically.
 

· Hydro-Dynamic
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I'd make it simple and get the $125 Spectrapure that is repeatedly touted here.
+1 :thumbup:
No kidding, I just totaled up the rebuild I suggested
and without buying extra tubing, a gauge or 2, a reducer and so on…

it's pushing $140 to rebuild his, maybe $130 with a standard membrane
which will cost more money over time than 99% rejection
which I'll get next time I replace my membrane.
 

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Discussion Starter · #8 ·
You guys may be right but im not doing any of it if im gonna spend 140$.....I just found out Air, Water, Ice is local and Im gonna take a ride down there next week on a day when I dont have the girls....Ill likely get a new system when I really NEED to start making ro/di water but for now, Im only doing 1 gallon water changes once a week. I really do want to get it down to 0ppm if I can, so If I can snag a DI cell for cheap.....I might do it and skip the rest of the upgrade.

I doubt Ill go through enough resin(making so little water over the next year)to make me regret it. Im likely going to get a bigger tank again eventually and Ill NEED to make more RO then. But that adventure is still months-ayear away...Thats when Ill pull the trigger and get a really good Water purification dedicated to making water for the tanks. Ill let you guys know how the Air, water, Ice visit goes.

Hey If I do just get the DI cell can I add it as an additional stage later on the a better RO/DI system?

BTW...you guys are awesome...just sayin:beer:
 

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What is your tap water TDS?
The tap TDS and RO only TDS are used to determine how efficient your RO membrane is performing or its rejection rate. Without knowing the starting number we have no idea is 16 is good or bad.

From personal experience with a Watts Premier drinking water system I can say it is almost always more expensive to add DI to a drinking water system than to add a drinking water kit to a reef quality RO/DI system. The reef system will have a lower micron sediment and carbon block filter so they do a better jb of protecting the RO membrane which is usually a 75 to 90 GPD version versus 15 to 25 GPD and everything else is usually better quality too, plus it will have important things like an inline pressure gauge. Better filters do a better job of protecting the RO so it works better and lasts longer so the DI does not have to work as hard. My softened tap TDS varies between 560 and 830, the Watts got that to 13-15 TDS and my DI lasted 150 measured gallons maximum. The Spectrapure I now own gets that tap TDS down to 2-3 and my DI lasts 1000 gallons or more. I can get 6-7 times more water out of the DI so the cost savings is huge.

You could buy a $125 Spectrapure and transfer your existing drinking water ASOV, and pressure tank along with a $6 check valve to it and be many $$ ahead.
 

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Discussion Starter · #10 ·
hey AZ I was hoping you would find this thread:D

Ill check the tap today at some point and get back with yall...Busy day today. is there a formula you use to figure waste/finished product?

I dont know if Ill go through 150 gallons of water this year with my little 6 gallon nano.....
 

· Hydro-Dynamic
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Why not just use distilled water for now? If you do 1 gallon water changes a week that will be less then a $1 a week.
What a brilliant idea!
Still should sample each jug for TDS levels unfortunately.
... is there a formula you use to figure waste/finished product?
Pg 16 post #239 in my active 40g thread
:dance:
just figured my membranes rejection rate =98.65% rounds to 99.
Wasn't even going to check it, but my RO water was 2ppm
which I was pretty excited about how long the DI will last now
given that figure.
Tap was 149 ppm - 2 (ppm) = 147 / 149 = .986577 x 100 = 98 + % rejection
and…the membrane is 18 months old :)
 

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Even with small reef systems a RO/Di could be a good investment, especially if you drink much water yourself and buy a lot of bottled drinking water or have home delivery. Adding a drinking water kit to a reef quality RO/DI is around $60 andpays for itself in a matter of weeks to months if you live in a warm climate like we do. We have drank RO water for over 20 years now and the system was paid for many many years ago and pays us now.
 

· Hydro-Dynamic
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Adding a drinking water kit to a reef quality RO/DI is around $60 andpays for itself...
I just put a tee inline and 2 valves. Shut valve to DI and open valve for RO
and costs aggressively under $60.
Maybe 1/3 the price. Darn valves are expensive 8-$9 ea.

What's wrong with drinking DI water?
 

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Nothing except is tastes very blah or bland, not refreshing at all. And it is expensive to produce compared to RO only so why drink something that tastes bad and costs more?

I always install a DI bypass valve as you described but I use it more for a point to test RO only TDS using my handheld TDS meter and a place to bleed off TDS creep. Its slower than molasses if you are using it to collect drinking water since it is not under pressure.
 

· Hydro-Dynamic
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Nothing except is tastes very blah or bland, not refreshing at all. And it is expensive to produce compared to RO only so why drink something that tastes bad and costs more?

I always install a DI bypass valve as you described but I use it more for a point to test RO only TDS using my handheld TDS meter and a place to bleed off TDS creep. Its slower than molasses if you are using it to collect drinking water since it is not under pressure.
I really don't mind DI for drinking and prefer it once the carbon
loses its initial freshness.

Post Membrane certainly, is under pressure, either DI or RO
with my 150 GPD takes ~10-11 mins for product, per gallon.
Nothing slows due to bypassing the resin, it's just a diversion.
 

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It is basically at atmospheric pressure once it passes through the membrane unless you have backpressure such as with a bladder or pressure tank or a closed valve like an ATO, other than that it is a trickle depending on the membrane rating and inlet pressure. It is also atmospheric through the DI too since there is little pushing it once the energy has been consumed passing through the membrane fabric.

I used to own a 150 GPD membrane and sold it. The rejection rate was much lower than my Select series 90 GPD membrane, both with and without a booster pump. Spectrapure only carried the 150 for a very short time as they could not get enough to pass their strict guidelines and were failing almost all of them.
 

· Hydro-Dynamic
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10-4 on the BP
I thought you were saying the bypass made it become a trickle.
I see what you mean.

My rejections running at 98.65% ATM with an Axion TF-1812 150
installed 1/2014. Last check something like 3.25 : 1 waste ratio.
It'll do for now. I am satisfied with those figures.
All in an eBay model that had twin horizontal DI cylinders
that you helped me rebuild better with your helps :thumbup:
 

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Discussion Starter · #20 ·
We strictly have only ever used our RO water to run through our kureg coffeemaker. Huge difference. My Buddy has sediment all over his and mine has none. I believe the makeup of TDS also contains certain beneficial minerals that get removed with the DI portion of our systems. If you use RO then your at least letting a little through In your drinking water/coffee/tea(although realistically we probably get most of that through diet). I like RO water.....it's all I'll drink.

So when I run the DI cell it should go like this right?

1st stage, second stage, RO, tee---check valve on the kitchen run(prevents TDS creep from the tank)-------ball valve on the DI run, DI cell, ball valve, some tubing for filling containers with RO/DI water......

The ball valves before and after the DI cell are to isolate the DI portion. Should I also have one on the RO only run to the kitchen?


My buddy gave me an interesting idea that I wonder if it would work. He was talking about running two RO membranes. After it goes through one you run the waste water through another. That way you cut back on waste water and improve the amount of finished product you get. I don't know if you would run it through the 1st membrane and then run both finished/waste through the 2nd one.... or if you just run the waste water through the second one....not that I'll do but since we're on the topic.
 
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