How is my RO/DI unit? going from 900ppm to 33ppm? (well water)

[Radioheadx14]

Water right out of the ro/di filter into a bucket (that i usually use to fill the tank w/ salt water or fresh water top offs) had a reading of 33-34ppm. our well water straight from the tap(after running through our water softener) is a little under 900ppm (i think its time for a softener change.)

My RO/DI unit does not have a booster pump installed, but i will get one as soon as i get some money. Does that sounds decent for a unit that runs with that high input water and a pressure of only 45psi? I checked nestle spring water, and it was about 75ppm. so i am content to know that my ro filter is more pure than spring water (that has additives.)

If i add a booster pump would the water tds reading get even more closer to 0?

[oct2274]

there is something wrong if you aren't getting 0 TDS water out of your unit. A good unit would take the water down to atleast 10 TDS out of the membrane when the water is going in is at 900 and after the DI stage you should be at 0. I would say your membrane is either a low quality unit, not seated properly, or is bad. Your DI stage is definitely exhausted if you aren't getting 0 TDS water. The resident water expert will be stepping in here shortly I'm guessing to make some suggestions and give his input.

[scottfarcuz]

Is it a new unit you are setting up?

What brand and GPD rating is it?

If new did you flush the carbon block, and let it run awhile?

[Radioheadx14]

yeah, i have already filled my 75g tank with it, and done several water changes. The GPD rating is 100... but i dont get anywhere close to that. I think it may be because i have well water and low PSI. and yes, i flushed everything when it was new. i let it run for an hour or two before i started using the water. Here is the model http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=120147608444&ssPageName=STRK:MEWN:IT&ih=002
I know its not the best brand, but others have said they had good results. I dont want to buy a new unit since i already bought and set this one up. I think it might be from low pressure.
Yeah, I'm sure AZdesertrat will give me some input.

If you do the math, it is a 96.5% rejection rate. I have heard people using well water with low PSI only getting around 85%

[Radioheadx14]

I just checked the bucket of RO water i made, instead of putting it in a bucket i have SW in (dummy) and now its at 15ppm.. which is better, but still not ~0

[oct2274]

your psi is fine(not the greatest) and it doesn't matter that it is well water. There is something wrong with your unit. Before i got my booster pump i only got between 30 and 40 PSI and my water going in was around 700. I had 10 coming out of the membrane and 0 coming out of the DI stage. It was obviously slower at making water.

[SlowCobra]

Well I will offer my 2 cents and some will come in and sing the praises of the unit you have. The Ebay specials, including the water general are less than stellar performers. Particularly if you have high TDS to begin with. The horizontal DI canisters do a horrible job and expend themselves quickly. There are MANY MANY MANY posts on the RODI subject. Just click through a few pages I am sure you are bound to find at least 4 or 5 different threads within the last week or 2.

AZDesertRat will eventually respond as water purity is his career, at least I believe that is what his occupation says. Regardless he has expert level knowledge in RODI units and will basically tell you what I have already said... Water General is, to put it not so bluntly, garbage.

[sjm817]

It would help if you could post TDS before and after the DI. Be sure it has run for a bit and is in a clean glass when you measure it.

[Radioheadx14]

i'll have to test that out when i get some time... if my DI sucks then i might remove it and add a vertical DI canister.

[Radioheadx14]

any comments on adding a vertical DI canister?

[Sea-nut]

I have a 50 GPD Pure Flo-2 RO/DI with the booster pump.
I noticed that the booster pump does not change anything,the ratio of waste water to pure water is about 7 to 1,I get about 20 gallons per day with or without booster pump,DTS of water after my house filter is 75 and after RO/DI unit is 6, last month I replaced all filters including Di filter but not the membrane the unit is only a year old.

[Radioheadx14]

hmm... Maybe i should look into getting a different DI filter then... maybe i will try the vertical DI canister... maybe thats my problem. Mine, now that i have ran it for a while, has parts where there is not any little filter spheres. It could be that my tds are a little high because not all the water is coming in contact with the DI media.

[oct2274]

the di canister is not the main problem, but most likely part. You should not be getting 33 TDS even before the DI stage.

[Radioheadx14]

it was really around 10-15..the bucket i put the water in has some salt in it... i was a dummy.

[kysard1]

<a href=showthread.php?s=&postid=10977287#post10977287 target=_blank>Originally posted</a> by Radioheadx14
it was really around 10-15..the bucket i put the water in has some salt in it... i was a dummy.

15ppm after RO is excellent performance if your starting water is 900. That would be over 98% rejection.

If you are still getting 15 ppm after DI, you just need to change the DI resin.

[Roland Jacques]

Do you still have the "stage 6 hooked up on this unit? If so it only to put "flavor " back into your water. It can also put TDS back in your water. For reef use 6th stage Carbon is not recommended. just remove that part.

You should check your RO water Before your DI section to know what's really going on in any RO-DI. Llike kysard said, if you are getting 98% rejection rate (18 TDS in your case) from your RO only, you're doing great.

The DI is straight forward you should always get 0 tds out of it.

[Roland Jacques]

<a href=showthread.php?s=&postid=10971466#post10971466 target=_blank>Originally posted</a> by Sea-nut
I have a 50 GPD Pure Flo-2 RO/DI with the booster pump.
I noticed that the booster pump does not change anything,the ratio of waste water to pure water is about 7 to 1,I get about 20 gallons per day with or without booster pump,DTS of water after my house filter is 75 and after RO/DI unit is 6, last month I replaced all filters including Di filter but not the membrane the unit is only a year old.

the boost pump should change your production rate, and your waste ratio rate.

If your getting 1:7 you have a problem. check your PSI at the membrane. and check your resistor.

[Sea-nut]

How do you check the resistor,also on my unit there is no PSI gauge.

[Roland Jacques]

I would check your pressure first. Yyou can buy a pressure gauge and tee it in right before your membrane. Lowes has the fittings and guage, The Filter Guys Online can get you set up with a PSI guage also.

[Sea-nut]

Thanks Roland
How do I check the resistor?

[Roland Jacques]

Resistors are trickier. some are external, some are adjustable, some are fixed, and some are internal. so it would really depend which you have. Better just to check PSI before going to the resistor checking...

[AZDesertRat]

To know how well your unit is performing and to troubleshoot it you need 3 numbers.
1. Tap water TDS.
2. RO only TDS before the DI.
3. RO/DI TDS

To get these numbers you need a clean TDS meter and a squeaky clean clear drinking water glass with absolutely no soap residue or water spots on it. Let the water run for several minutes before taking the RO and RO/DI samples so it has a chance to pass any TDS creep.

I will also chime in and say you could have done much much better on the unit you selected, its strictly bottom of the barrel for quality. There are hundreds if not thousands of posts here on RC to back this up.

With the 100 GPD unit you will be lucky to get 90% rejection or efficiency, if it was a 75 GPD that number would be more like 96-98% with RO only. With the small horizontal DI you may never see a true 0 TDS, its just a poor design, or actually lack of a design that causes this. Horizontal tubes promote short circuiting or channeling so not all water comes into contact with DI resin and bypasses treatment. You can help the situation by turning the DI up on its side so the water enters from the bottom and flows out the top but it wil still never equal a true 10" canister and cartridge type engineered DI system. Plus this will not improve the RO situation at all only act as a crutch for a poorly performing membrane and wear out quickly.

Provide the three TDS numbers and we can probably make suggestions on how to improve your situation.

Sea-Nut,
Flow restrictors should provide 4:1, 4 waste to 1 good. 7:1 means you are flushing the membrane more than necessary and lowering pressure thus reducing good water output. Get an adjustable flow restrictor or a capillary tube type that can be trimmed to fit your exact coonditions.

[sjm817]

My Filter Direct (Water General) is pretty decent. The original membrane gave me a TDS of 4 before the DI. I changed it out to a Filmtek, and it also gave me the same TDS of 4. No better. Lots of units have horizontal DI chambers, including some of the more popular brands here, not just FD.

As above, do a proper test and see what is going on. 15 from 900 is very good. It may be you just need a good DI.

[Radioheadx14]

Yeah, i figured for having such crappy well water, and 15-10 come out its not doing too bad.. but i'd rather have 0. I am home sick today so maybe i'll check all this today. I will also try turning the DI verticle... if that doesnt help, i may just buy a canister DI filter. I saw them for 30 bucks on one of the sites recommended.

[AZDesertRat]

Is the 15 after RO only or after RO/DI ? If its RO its pretty good , if its RO/DI its terrible and a potential problem. Have you checked the three points I asked about?

[kysard1]

Get an adjustable flow restrictor or a capillary tube type that can be trimmed to fit your exact coonditions. [/B]

Where could one get these ?

[AZDesertRat]

Any of the RO/DI vendors here on RC should be able to set you up with either.
www.buckeyefieldsupply.com
www.spectrapure.com
www.thefilterguys.biz
www.purelyh2o.com
www.melevsreef.com
are a few examples. I know Spectrapure uses the capillary tube and I really like them because I can trim it to fit my exact water temperature and pressure so I get exactly 4:1 waste ratio. Buckeye has the adjustable ones which would be a good choice if you get large variations in temperature due to seasonal changes. The others I am not sure of but they should be able to supply them.

[Radioheadx14]

My RO only is not that bad at all... it started coming out at 125ppm and i freaked... but after letting it run for several minutes it dropped all the way down to 18ppm. I removed the DI unit and hung it vertical and after running that for a little while its still at around 11-10ppm.

Should i go for one of these then? http://www.purelyh2o.com/product.php?productid=16194&cat=251&page=1

[AZDesertRat]

Get an add on DI canister and refillable cartridge and it should get you to 0 or very close. Your DI resin is way overdue so discontinue using it immediately. You are adding phosphates, silicates and nitrates back into the water by using it past its prime. DI resin releases weakly ionized substances once it nears exhaustion and you have gone past that point.
As an example, my tap water TDS averages 835, my RO only is between 5.2 and 6.3 using a very good HM Digital COM -100 meter which is one of the only ones that will read in tenths. My DI is 0 and stays that way fpr about 630 gallons per cartridge due to the 99.23% efficiency I am getting from the RO membrane.
With your high TDS tap water you would be money ahead to purchase the Spectrapure add on MaxCap DI system as it will last a guaranteed 3.5x longer than any other DI cartridge.

[craftedpacket]

Not trying to hijack this thread, but have a question about RO/DI...Can you have 0 TDS water and still have things in it that can harm the tank? I have a bad hair algae problem, but always use 0 TDS water for top off and water changes. My city water is bad...around 700ppm on my tds meter. I am going to test the water coming out of my RO pre DI tonight and see what I get, i go through DI resin very quickly...I have a Typhoon 5 state from AirWaterIce. At 700PPM tap water how long will a membrane last? I have been on the same membrane for a little over a year.

[AZDesertRat]

Yes you can. Some of the weakly ionized substances like silicates and phosphates may not show up on all TDS meters if they are not extremely sensitive in the low range. Thats one reason I like the COM-100 since it does accurately read down to 0.1 resolution unlike other meters. Inlines are the worst since they are not temperature compensated and can be significantly off if the water and air temperature are not exactly the same.
The life of a membrane depends on several things two of which are how much water you make and more importantly how good of prefilters and carbons you use and how often you replace them. Cheap filters pass lots of solids through and do little to protect the membrane.
I recommend using absolute rated prefilters in the 0.2 to 0.5 micron range and 0.5 micron carbon blocks. Absolute rated filters actually trap particles down to and including their rated size unlike nominal rated filters that trap a percentage of particles at their rated size but can pass just as much on.
Cheap carbons can only last as little as 300 gallons while the 0.5 micron Matrix can last up to 20,000 gallons easily if its preceded by a 0.2 or 0.5 micron prefilter. You always want the prefilter to be smaller than the carbon so the carbon does not have to function as a second prefilter and wear out prematurely.

By using high quality filters it is not unheard of to have an RO membrane last 6 to 10 years. With cheap filters 18 months to 3 years is about the maximum life as it ends up building up crud and failing even if its kept at a 4:1 waste ration as recommended.

[Radioheadx14]

Could you recommend why types of filters i should put in my 3 pre-filter canisters? I have well water, and i heard that i should have chlorine at 0... so do i need carbon? also what else should i use in it?

[kysard1]

Understand that 5 grams of Mysid shrimp contains 65 mg of phosphate. 5 Gallons of water at 1 ppm PO4 (extremley high for after RO/DI) only gives 19 mg of phosphate.

What this means is your feeding is a much more likely cause of the algae.

[AZDesertRat]

Phosban or other granular ferric oxide or ferric hydroxide products can make quick work of phosphates once they are in the tank but only RO/DI will take care of the water you are introducing to the tank. Its best to cut it off at the source and alternately treat the symptoms with GFO. Overfeeding is a big cause of water problems but still only use high quality water for replacements and to start with and you reduce the chances of problems tremendously. Phosphates are only one of the possible contaminants that RO/DI takes care of.

As for filters you can get them at most any of the vendors I ahve already suggeste but I get mine at Spectrapure as they only carry the best and I will not compromise. I use a pleated 0.2 micron ZetaZorb which has 10x more surface area even though it is a smaller micron size so it is less prone to plug. Then I use a 0.5 micron carbon block which again is almost absolute rated so nothing gets passed on to the membrane that is larger than 0.2 microns so it lasts much longer and works much better.

I then have a dual membrane system with two Spectrapure Select hand tested membranes, one is a 90 GPD and the other is a 150 GPD for a total of 240 GPD production. I don't make 240 GPD but the 10 gallons per hour means it cycles much quicker so less waiting around for water changes.

Then I use the MaxCap DI cartridge followed by the SilicaBuster cartridge for true 18.2 megaohm resistivity semiconductor grade water.

[kysard1]

Then I use the MaxCap DI cartridge followed by the SilicaBuster cartridge for true 18.2 megaohm resistivity semiconductor grade water. [/B]


Don't think that you need water this pure to have a successful reef tank.

Every day you feed your tank you are adding a few orders magnitude N and P that the worst RO/DI system would add in top-off water.

Also when you do a water change you are adding PO4, NO3, and Silicate just from the impurities in the salt.

Its not worth it to spend big $'s to produce semiconductor grade water only to mix it with a salt that will yield 0.1 ppm NO3 (as almost all salt mixes do.)

Now if you have copper or Arsenic in your water supply you are going to have to make the investment for high purity water.

[AZDesertRat]

The consistency is easily worth the investment. No question in my mind and I'm a state and EPA certified treatment plant operator with well over 30 years of hands on experience.

[Roland Jacques]

AZ where do you get a pleated 0.2 micron ZetaZorb?

[AZDesertRat]

Spectrapure