ro/di still have tds

[jay13]

Hi, just put in a brand new ro/di unit and went from 340 tds to 6 tds. is this normal? thought it should be 0 tds. also just a trickle/ drips come out of di line. is this is a normal flow rate? 75 gpd ro filter maybe i just expected more flow.

[EMUreef]

Hi, just put in a brand new ro/di unit and went from 340 tds to 6 tds. is this normal? thought it should be 0 tds. also just a trickle/ drips come out of di line. is this is a normal flow rate? 75 gpd ro filter maybe i just expected more flow.

how long has water been running through the filter?
slow trickle is pretty common, usually do to poor pressure in the house, you can always buy a booster pump to get better pressure.

[Rabidgoose]

Let it run for a while....waste some water. First time using it I would say throw away a 5 gallon pail full of product water. A trickle is about right, if it is a 75 gpd unit at optimum production that is only about 1 gallon every 20 minutes.

[jay13]

running for 24 hours now, inline pressure gauge ordered to check that. refilling my180 and sump after the crash and wow it just feels like it is taking forever. i guess if the tank and 75 gallon sump are full in four days i will have my answer to the flow portion. still i expected 0 tds and am getting 6.

[Rabidgoose]

lol...yeah...it takes a long time. If its been a day I would have expected zero by now as well depending on the unit you have. Production however depends on more than just pressure, few of us get the advertised amount.

good luck..........chuck

[dlhirst]

You could have a defect in the RO membrane. That would allow things through that shouldn't normally get through. Is it really new, or just " new to you".

[jay13]

brand spankin new, installed all the filters myself. still at 6 tds it is over 98% efficient........ way better than the 340 tds!

[Heidi]

Hi, just put in a brand new ro/di unit and went from 340 tds to 6 tds. is this normal? thought it should be 0 tds. also just a trickle/ drips come out of di line. is this is a normal flow rate? 75 gpd ro filter maybe i just expected more flow.
What is TDS?

[dlhirst]

Total Dissolved Solids - the salts and minerals found in "clean" water.

[Joefish]

Have you calibrated you TDS meter recently?

[Synergy]

Running very cold water through you RO/DI will severely cut down on your production rate. Optimum temperature for input water is around 70 Fahrenheit. Only problem with that is if you aren't careful and the water gets to hot you can destroy your RO membrane. Usually simpler to just turn on the cold water and be worry free, but in the winter months production can be painfully slow.

I know some people run their incoming water line through a bucket of warm water to heat the incoming water to improve production, might be something to consider, especially with the amount of water you are making.

[AZDesertRat]

OK, lets start from the beginning.
What system did you purchase, what does it contain as far as prefilters and carbons and in what micron ranges, what brand and model membrane is it and how is the DI configured as in is it a full size 10" canister style that is refillable or is it a horizontal on top either refillable or a throw away?
All these things make a difference
Next what are your incoming water pressure, water temperature and tap waterTDS readings?
What is your waste ratio?

Everything above has a direct bearing on how well a RO or RO/DI system works and how long the membrane and DI resin last.

In the beginning when you first set a system up you should do several important things and in the correct order.
1. If the filters are all preinstalled, remove the carbon(s) and disconnect the 1/4" line which leads from the carbon up to the RO membrane housing at the membrane end. Hook the unit up to a cold water supply and flush the prefilter for several minutes to remove any antimicrobial coatings, glues and binders so they do not foul the carbon block.
2. Install the carbon block, hopefully its a good unit and only contains the one necessary carbon block, multiples are unnecessary and can actually lead to problems. Again turn the water on and flush both the prefilter and carbon block to remove any fines or carbon dust so it does not fould the RO membranes surface.
3. If you have multiple carbon blocks add the second one if you wish and do the flush process again. If you have granular carbon at this point I suggest throwing it as far as you can as granular media has no place in front of a RO membrane since it grinds itself to dust and ends up ruining your membrane. If you have a GAC filter we need to talk further.
4. Now hook the line back up to the RO membrane and disconnect the line to the DI filter or remove the DI resin or cartrige and flush 3 to 5 gallons out of the RO membrane. This will be a slow process as you have already noticed, every a full 75 GPD under perfrct conditions is only about 3 gallons per hours at best.
Watch your TDS readings while flushing the membrane, you should see it drop to a low somewhere around 96-98% less than the tap water TDS, you are fully flushed at this point.
5. Now install the DI cartridge or resin or hook the line back up and do a final rinse up of the resin, again watching the TDS meter until it drops to 0 TDS. ANY RO/DI should be capable of 0 TDS, the mark of a good system is how long it remains at 0 TDS on each DI refill.
6. Check your waste ratio. Using a measuring cup and clock or watch, time how long it takes to make equal amounts of treated water and waste water. The waste ratio should be very close to 4:1 or 4 times as much brine as permeate or treated water.

Many if not most vendors neglect to tell you how to properly flush a system for use and the result is shortened filter life and lower qater quality. When you talk rejection rate or removal efficiency we are talking about the TDS of the tap water and the RO only water, not RO/DI TDS.

Water pressure and water temperature have the greatest effects on RO GPD and even water quality. Dow Fiilmtec tests their membranes at 50 psi and 77 degrees F., that does not mean these are the ideal parameters its just a way to set a standard. In fact higher pressures will produce not only more water but higher quality water as membranes work better under higher transmembrane pressures, I run my personal RO/DI at between 90 and 100 psi with a booster pump which allows me to get 99.35% rejection rate with RO only and closer to 120 GPD out of a 75 GPD Dow membrane. Water temperature also has an effect and truthfully colder water treats better than warmer water and again will give you lower TDS since it is more dense aor less viscous so fewer contaminant particles pass through the membarne fabric. The disadvantage of colder water is it reduces the GPD but for most of us with a 75 GPD system we can still make more than we need in a day anyway. Heating the water in a bucket is extremely expensive since heaters cannot keep up with the water flowing thru the tubing. Trying to blend or temper hot andcold is also a very poor idea since it is the number one way to permanently damage a RO membrane. Remember being in the shower when someone flushed the toilet or started the washing machine? You got your tush scalded and thats the same thing that melts a RO membrane. Membranes cannot tolerate anything over 113 degrees F and thats not really all that hot, don't take that chance.

Lets start out with your particulars, if you can answer the first several questions I had I'll bet we can solve your problem.

AZ

[jay13]

ebay purchase, seems like they are all the same with a company logo stuck to them before sale. the filters on the other hand are as follows: 5 micron sediment filter, 5 micron carbon filter, 1 micron carbon filter, ro membrane is dow filmtec 75gpd, the di is the 10 inch canister with color change resin. flow rate seems to be right on from what i see in the tank, just seemed slow to the ro/di newbie. pressure and temperature are unkown right now. it is cold and right off the main line from the meter post water softener. tap water tds was 340. tds meter is the fish doctors, not mine so it may be off. hope this helps.

[AZDesertRat]

RO and RO/DI aystems are not all the same, far from it in fact. Just because visibly they look the same it gets a lot of folks in trouble.
If your tap water TDS is 340 there is absolutely no reason your RO only TDS is not in the 5-7 range at the most even with an ebay special and your RO/DI should be 0 for a long time. With a good system your RO only should be no more than 3 and the DI should last over a year. Unfortunately you get what you pay for with RO/DI and a low initial cost often ends up costing much much more over time between the cost of replacements and the cost to upgrade to work the way it should.

Without knowing more specifics like pressure, temperature, waste ratio, Tap water, RO only and RO/DI TDS its hard to troubleshoot a system. You need to get an inline pressure gauge and a nice handheld TDS meter such as they HM Digital TDS-3 or TDS4-TM so you can get an idea what you have.

Not sure what you paid or what you got but for comparisons, look at the CSPDI found here for $199. It comes with a 0.5 micron absolute rated prefilter, a 0.5 micron 20,000 gallon carbon block, a treated and tested high rejection rate 90 GPD RO membrane, 20 oz of custom blended reef specific DI resin in a 10" vertical refillable canister and cartridge, an inline pressure gauge, a dual inline TDS meter, a capillary tube flow restrictor you yourself trim for an exact 4:1 waste ratio and more. Plus its backed by a company in the RO business for over 25 years in a brick and mortar building in Tempe AZ USA that is not going anywhere.
Untitled Document (http://www.spectrapure.com/email/customer-appreciation.html#1)

You really do get what you pay for with RO/DI.

I am not affiliated with them in any way but as a water treatment professional I recognize quality and their stuff is all I use after having owned many others over the past 20 years.

[jay13]

well the actual filters are different for sure. but the housing? must be the filters themselves you speak of. i have looked at enough of them to know they are all basically the same when it comes down to the plastic pieces. the filters themselves though i am sure are a huge difference. home tds meter on the way, hard to trust a tool you have no personal knowledge of. so i have a system with three 10" pre membrane containers, an ro membrane container and the 10" di container. 340 tds. when i change filters what should i replace them with?

[AZDesertRat]

Believe it or not there are a lot of different quality housings and fittings on the market too. Better companies use housings and components that have been subjected to the rigid ANSI/NSF and UPC certification processes. This ensures the plastics can not only withstand the working pressure but are also safe to come into contact with drinking water or foodstuffs. Many lower end units still use compression fittings while all the better ones use John Guest style speed fittings. Lower end systems rarely supply pressure gauges or TDS meters while the better ones do.

As for filters I go with no larger than a 1 micron prefilter, 0.5 is better and absolute rated is way better than nominal rated. A single good 0.5 or 0.6 micron carbon block is more than sufficient, something like the KX Matrikx+1 Chlorine Guzzler. With maybe $5 in parts and 10 minutes time you could then convert the additional 10" canister to a DI filter so you would have dual DI which would really give you bang for your buck. I would also take the time to calculate your waste ratio, this is one of the most misunderstood and most critical parts of a RO or RO/DI system and most vendors supply a fixed non adjustable flow restrictor and we all know everyones water conditions are not the same. RO or RO/DI is not a one size fits all if you expect it to both perform and last any length of time. The wrong restrictor or waste ratio can cause a RO membrane to fail prematurely or it can send too much to waste reducing pressure at the membrane wearing your DIU out faster. Make sure it is 4:1 and if not get a capillary tube flow restrictor and take the time to properly set it up youself.

[jay13]

sounds good, i will get into it this weekend and report back what i find. then again just heard the walleye are on down in the maumee river so i will have to see.........

[AZDesertRat]

Priorities! Hope you catch a big one.....

[wilco1rd]

Send it back and get a typhoon from airwaterice.com ...guaranteed 0 TDS. I just got one with my tap water over 1000PPM and now 0 With typhoon!:)

[jay13]

here it is, from Premier Water
REVERSE OSMOSIS DI/RO AQUARUIM REEF WATER SYSTEMS 75GPD - eBay (item 270540955923 end time Mar-28-11 13:57:14 PDT) (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270540955923&ssPageName=STRK:MEWAX:IT#ht_4707wt_754)

[AZDesertRat]

Let me give you a little history of my RO and RO/DI systems.
I started about 20 years ago with a Watts Premier RO system from Costco or whatever it was called at the time. I am not sure if the Premiers are related or not but I don't think so.
I spent quite a bit of time and money revamping the system to mimic a Typhoon III, better prefilters, better carbons, I even visited Watts Premier and had them upgrade me to a 75 GPD membrane which they bench tested for me. I installed an additional 10" canister and installed a refillable DI cartridge and bought a pressure gauge and TDS meter.

The moral of that story is I had a ton invested and it still only lasted 150 gallons of RO/DI per DI refill no matter what resin I used.

Next I sold that system and bought a real Typhoon III. It still only lasted 150 gallons per DI refill and I was very unhappy since I had invested all that money twice and still did not have what I thought I should.

Next I bought a Spectrapure MaxCap 90 GPD system. I installed it taking the few extra minutes to flush the filters and to trim the capillary tube flow restrictor for my exact water conditions. With absolutely no other changes, my first MaxCap DI cartridge lasted a documented 830 gallons! Success at last.
The first replacement MaxCap DI cartridge went just over 1000 gallons before it started reading 1 on the TDS meter. Better still. The second replacement went just a bit longer and when I talked to Spectrapure they said they had perfected the MaxCap resin blend even further. I was overjoyed.
I upgraded the 90 GPD MaxCap to a dual membrane system capable of 180 GPD and was still getting the same 99.23% rejection rate and DIO was lasting what seemed to be forever, I replaced the first SilicaBuster DI cartridge and a little over 3000 gallons of RO/DI water. I installed a 1" flow meter on the wall just to document the usage.

I was so happy with the MaxCaps I broke down and bought the new at the time MaxCap UHE ultra low waste system. It is running at slightly less tha 1:1 waste ratio and 90 psi pressure with a booster pump. The system is approaching 3 years, yes 3 years old and I am still on the original SilicaBuster DI cartridge and only the second replacement MaxCap DI cartridge.

With RO/DI you really do get what you pay for and cheap is not the answer. It ends up costing you from day one.

When buying a system look for things like low micron absolute rated prefilters, I use a 0.2 micron pleated absolute filter that has 10x the surface area of a normal filter and have only replaced it once in the almost 3 years. I do watch the pressure drop closely using two gauges though. You want a single, yes single not two inferior, carbon block. One 0.5 or 0.6 micron Chlorine Guzzler type carbons is more thansufficient ,even if you have chloramines which is really a burden on the DI not the carbon as many lead you to believe.
You want a quality name brand RO membrane, notice the Premier units do not state the brand name or model number anywhere? Big Red Flag! No secrets, no surprises. If they don't tell you upfront then look elsewhere, its probaby a knock off or no name and probably not ANSI/NSF certified.
Look for a full size vertical DI filled with fresh resin, a minimum nuclear grade or semiconductor grade is good but companies like Spectrapure blend their own resins in house based on thousands of hours of testing, both field or real world and bench testing.

You want an inline pressure gauge so you can watch pressures and pressure drop. You want a TDS meter, either dual inline or handheld, I have multiples of both and prefer the handhelds due to their accuracy and portability, I can test water anywhere I want to not two dedicated locations.
You want a capillary tube flow restrictor you trim yourself, everyones conditions are not the same and there is no one size fits all.

These are just a few pointers on what to look for and there are several good vendors who can provide most of the above. Spectrapure is the only company I am aware of who treats all their membranes with a special treatment then tests them for quality control and ships them wetted. They are also the only company that mixes every ounce of their own DI resins in house.
Check out the ale flyer here:
Untitled Document (http://www.spectrapure.com/email/customer-appreciation.html#1)

But also check out the 75 GPD Premium systems here:
www.buckeyefieldsupply.com

and the reefkeeper here:
Melevsreef.com - Welcome! (http://www.melevsreef.com)

and the Optima series here:
FL Aquarium Water Filters Reverse Osmosis Booster Pump GFO Nitrate DI Carbon (http://www.purelyh2o.com)

All can supply what you need at a competitive price and do not hide anything from you.

[jay13]

"You want a capillary tube flow restrictor you trim yourself"

looked this up. seems it is an insert on the good water out side of the RO membrane. attaches to the 90 degree elbow between the elbow and the 1/4 line. so how do you trim it then? and why? they all say preset. i assume for the true 1:4 ratio that pigtail is trimmed?

also, this may be all in vain. i took my water in to the hospital i work at and checked it in the lab with a tech. they have a tds meter there for the DI systems they use for all the ice machines and it read 0. regardless i will use the advice to "fix" this system to the point that i am satisfied and get 0 tds with the meter i ordered for home use. thanks

p.s. the system i bought has dow filmtec 75gpd membrane. i always email the seller first for info like that, he sent me the info on the prefilters too but i cannot remember all that

[AZDesertRat]

The capillary tube flow restrictor looks like a piece of spaghetti with a small flange on one end. It inserts inside the waste line, not good line, and you trim it according to the included directions.
Look on pages 8 through 11 of this manual for the direction on how to calculate your permeate and waste flows and how to trim the restrictor to length.
http://www.spectrapure.com/manuals/PRINTER_FRIENDLY/CSPDI.pdf
You would remove your existing restrictor, insert the untrimmed capillary tube, measure the product and waste flows with a measuring cup and calculate the waste ratio. Based on what you find you then remove the restrictor and using a new razor blade you trim it to the total length indicated in the directions. Its really easy and takes just a few minutes. You don't want a preset restrictor, you are no better off than before.

[jay13]

cool, i will order it right now. well, soon. is there a brand to stick with or ones to stay away from? looks like a pretty simple piece of equipment. and just from watching i bet the ratio down there is about 1:8!!!!!

[AZDesertRat]

They are $5 at Spectrapure and probably most other places as well, I think Buckeye is close to that too.
I really trust Spectrapure since they exhaustively test everything they sell before introducing it. They depend on their 25+ year reputation in the business. Russ at Buckeye is also a great guy to deal with, I have bought many things from him over the years too.

[jay13]

so the fr-60 or the fr-90 from spectrapure? do i go above or below my gpd fow rate of the membrane. i assume above and trim down?
fr-90 cut to 4 inches it appears.........

[AZDesertRat]

If you have a 75 GPD membrane then go with the FR-90. You will not know what to trim it to until you insert it and measure your product and waste flows. It usually ends up like 9" or so on average but everyones conditions are different. It takes into account pressure, temperature, backpressure, TDS and more.

[jay13]

so spectrapure's sheet is a rough guide, what increments should be trimmed at a time? an inch or less? these tubes look really long and their chart states four inches for the fr-90 at 75gpd. also what is the relationship of tube length and water waste? is it the longer the tube the more waste or the opposite?

[jay13]

read it again, it is all based on water calculations. i see the light now. i will grab a graduated cylinder from work tonight and test it.

[AZDesertRat]

What you are seeing in the first colum is the mL per minute you will discover once you have installed the restrictor in your system initally, not what it is today or what it should be. You have to install the uncut restrictor, test your product rate, then look that rate up on the chart and trim accordingly.
This is from the Spectrapure Sponsors Forum on some of the various sites:
Flow Restrictor Basics.... - 3reef Forums (http://www.3reef.com/forums/spectrapure/flow-restrictor-basics-76423.html)

[jay13]

just did a little more digging. it has a "flow restrictor" that is inline and cylindrical. i take it those are junk?

[AZDesertRat]

Yes, that is a fixed flow restrictor and everyones conditions are different. Get a capillary tube and trim it according to your exact conditions, your membrane will last longer, produce more water and produce better water. Most restrictors waste too much which reduces the pressure available to the membrane reducing both efficiency and GPD. You water bill and cost per gallon of treated water will go down too.

[jay13]

cool thanks

[jay13]

just an update to this thread. i installed a dual inline tds meter and recalibrated it to 10% below the 342 ppm stock solution as directed by the manufacturer. my original tds from the tap was 340ppm. this was taken on a handheld tds meter of unknown calibration when i started this thread. dial ahead till now and the tds post water softener is 160 ppm and is 0 ppm after the rodi. i believe this whole time i was getting incorrect readings from a poorly calibrated meter. buy your own test equipment kids!

[Sir Patrick]

If you ever want to borrow one thats spot on, let me know.

[AZDesertRat]

I would not trust the dual inline since it is not temperature compensated so can be substantially off if the air temperature and water temperature are not EXACTLY the same, which is rare. A good ATC handheld is much more accurate and dependable. I have two dual inlines and don't even turn them on anymore since they never agree with my AP-1 or COM-100.