I need to replace my RO unit, I'm thinking RO/DI

[thang45]

Can someone please help me.
I have a Pinnacle Series 35 gal RO Units. For the first time last month I replaced the carbon and sediment cartridge because the water output was low. But after a few weeks running with the new carbon and sediment cartridge, the water output is low again. I think I need to replace the membrane.
To me replace the membrane the same time as the cartridges is not cost effective. I except the membrane to last at least 2 times longer than the carbon and sediment.
Anyways, I saw SpectraPure MaxCap RO/DI System, 90gpd w/ Pressure Gauge & Purity Monitor on sale. Is this a good unit or I should look for something else?
I have a 90gal tank.
any help is greatly appreciated.
thanks

 

[scsinet]

All RO units are pretty much the same as the cartridges are what matter, and they are only made by a handful of manufacturers.
So if it's a good price, then go for it.

 

[thang45]

Originally Posted by SCSInet
http:///forum/post/3150810
All RO units are pretty much the same as the cartridges are what matter, and they are only made by a handful of manufacturers.
So if it's a good price, then go for it.
So all are the same? I thought certain models are better than then others.

 

[scsinet]

Where units differ more than anything else is the type and quantity of modules, and addtional features.
For example, a unit with a high-silicate rejecting membrand and/or DI stage is better than one without, higher GPD production rates, etc are all examples. Additional features might include pumps, pressure gauges, and inline TDS meters.
But when comparing apples to apples, two units from two different vendors with the same quantity and type of cartridge are not going to be much different. RODI units are one of those few things where generic is perfectly okay.

 

[thang45]

Originally Posted by SCSInet
http:///forum/post/3151010
Where units differ more than anything else is the type and quantity of modules, and addtional features.
For example, a unit with a high-silicate rejecting membrand and/or DI stage is better than one without, higher GPD production rates, etc are all examples. Additional features might include pumps, pressure gauges, and inline TDS meters.
But when comparing apples to apples, two units from two different vendors with the same quantity and type of cartridge are not going to be much different. RODI units are one of those few things where generic is perfectly okay.
thanks for clearing that up for me.

 

[stanlalee]

Originally Posted by thang45
http:///forum/post/3150848
So all are the same? I thought certain models are better than then others.
yep, the only difference are the number of filters. Basically a RO unit is a RO unit, you have a sediment filter, a carbon block, a membrane and anything after that is optional post filtering or bells and whistles (or however you spell that). More than likely you are clogging the sediment filter quickly as its pretty much the only thing that can clog (particles large enough to clog anything or that arent dissolved shouldn't get past this point). $100 RO unit with 2.5" sediment filter, carbon block, 50gph membrane and carbon block post filter will perform exactly as a $250 RO unit with a 2.5" sediment, carbon, 50gph membrane and post carbon block IF the quality of the internal filters are the same. Since they have to be replaced anyway you arent but a replacement schedule away from the same exact water quality (assumming they even put better filters in the $$ ones. Most use the same old dow filmtech membranes and the carbon and sediment filters are so cheap the difference between premium and junk are like $5-10). Mostly you are paying for unneccessary bells and whistles (sort of like leather seats making your car more desireable but doesn' make it perform any better) or sometimes just good old fashion mark up.

 

[thang45]

Originally Posted by Stanlalee
http:///forum/post/3151233
yep, the only difference are the number of filters. Basically a RO unit is a RO unit, you have a sediment filter, a carbon block, a membrane and anything after that is optional post filtering or bells and whistles (or however you spell that). More than likely you are clogging the sediment filter quickly as its pretty much the only thing that can clog (particles large enough to clog anything or that arent dissolved shouldn't get past this point). $100 RO unit with 2.5" sediment filter, carbon block, 50gph membrane and carbon block post filter will perform exactly as a $250 RO unit with a 2.5" sediment, carbon, 50gph membrane and post carbon block IF the quality of the internal filters are the same. Since they have to be replaced anyway you arent but a replacement schedule away from the same exact water quality (assumming they even put better filters in the $$ ones. Most use the same old dow filmtech membranes and the carbon and sediment filters are so cheap the difference between premium and junk are like $5-10). Mostly you are paying for unneccessary bells and whistles (sort of like leather seats making your car more desireable but doesn' make it perform any better) or sometimes just good old fashion mark up.
How about the bells and whistles in the SpectraPure MaxCap RO/DI System, 90gpd? It says DI WATER at HALF the COST!

 

[stanlalee]

Originally Posted by thang45
http:///forum/post/3151289
How about the bells and whistles in the SpectraPure MaxCap RO/DI System, 90gpd? It says DI WATER at HALF the COST!
its a $350 unit with dual TDS meters. nonsense plain and simple. you are paying for the TDS meters and spectrapure name. it has quality filters and membrane but thats not where your money is going as like I stated the cost difference between great and cheap are next to nothing. minus the dual TDS meters and spectrapure name you can get the same quality and water quality for half that. the GPD is irrelavent to cost and are a membrane and flow restrictor change away from increasing or reducing. less is actually best for filtration. zero readings are TDS is zero TDS readings and the internal filters and incoming water quality are the only variables that make a difference. buy a hand held TDS meter for $20.

 

[scsinet]

Even less than half the cost. I bought mine online for $150, it's a 100gpd system. It also has 5 stages (2 sediment stages).
TDS is nearly perfect (which I measure with a $20 handheld meter).
So my investment is 170, still less than half of spectrapure.
Spectrapure units have pretty labels. Gauges and readouts also look impressive. If you want to spend the money for looks, that's cool (Been there, done that bro), but if you want me to justify $350 worth of "functionality" sorry, no can do.

 

[reefjunkiee]

Originally Posted by SCSInet
http:///forum/post/3151341
Even less than half the cost. I bought mine online for $150, it's a 100gpd system. It also has 5 stages (2 sediment stages).
TDS is nearly perfect (which I measure with a $20 handheld meter).
So my investment is 170, still less than half of spectrapure.
Spectrapure units have pretty labels. Gauges and readouts also look impressive. If you want to spend the money for looks, that's cool (Been there, done that bro), but if you want me to justify $350 worth of "functionality" sorry, no can do.
actually you are paying more for the membrane of a specrapure, they are high end. your 100 gpr ro mebrane has a high rejection rate, meaning your DI gets used up much faster than say the 75 GPD filmtek.i believe the 100 is 90% and the 75 is 98% with spectra you get higher GPD at a nice 98%.

 

[thang45]

Originally Posted by Stanlalee
http:///forum/post/3151305
its a $350 unit with dual TDS meters. nonsense plain and simple. you are paying for the TDS meters and spectrapure name. it has quality filters and membrane but thats not where your money is going as like I stated the cost difference between great and cheap are next to nothing. minus the dual TDS meters and spectrapure name you can get the same quality and water quality for half that. the GPD is irrelavent to cost and are a membrane and flow restrictor change away from increasing or reducing. less is actually best for filtration. zero readings are TDS is zero TDS readings and the internal filters and incoming water quality are the only variables that make a difference. buy a hand held TDS meter for $20.

Originally Posted by SCSInet
http:///forum/post/3151341
Even less than half the cost. I bought mine online for $150, it's a 100gpd system. It also has 5 stages (2 sediment stages).
TDS is nearly perfect (which I measure with a $20 handheld meter).
So my investment is 170, still less than half of spectrapure.
Spectrapure units have pretty labels. Gauges and readouts also look impressive. If you want to spend the money for looks, that's cool (Been there, done that bro), but if you want me to justify $350 worth of "functionality" sorry, no can do.
How about if the unit is going for $249? Is that a deal or still a bit high?
I'm looing at $80 differences based on your $170.
Originally Posted by reefjunkiee
http:///forum/post/3151356
actually you are paying more for the membrane of a specrapure, they are high end. your 100 gpr ro mebrane has a high rejection rate, meaning your DI gets used up much faster than say the 75 GPD filmtek.i believe the 100 is 90% and the 75 is 98% with spectra you get higher GPD at a nice 98%.
I saw the same info on some website.
Anyways, I call support and they told me that my flow restriction line may be clogged and that is my RO output is low. Before I was getting 1:4 ratios with 67psi, and now I'm getting 1:5 or 1:6 ratios.
Could the flow be clogged? I’ve removed the waste line but cannot tell.

 

[posiden]

I am by no means an expert on RO/DI units. However, The rejection rate is what you want to look at. The membraine of any unit is what makes the unit what it is. Not the housing. The DI resin will have to work at an increased rate baised on the rejection rate of the RO membraine.
The number of stages means nothing. It is just a marketing tool.

 

[stanlalee]

here is there explanation. You can buy it if you want to (basically testing to ensure they source only 98% rejection rates. I assure you the source is still the same wether or not the membranes are or arent) just keep in mind we didn't just start using RO units and TDS units yesterday so if you think your going to save money with longer lasting DI filters using spectrapure go ahead and buy it. Its going to take buku DI refills before you start reaping the savings even if you do buy their pitch.
Why is 1 or 2% so important?? A 2 % increase in rejection from 96% to 98% can double your DI cartridge(s) life. Over the life of the membrane that can save you big $$$ in DI cartridges! That is why our hand selection and proprietary testing (we sometimes reject more than half that do not meet our SPEC of >98.0% rejection) is worth the extra cost. Who else labels their membranes with actual rejection rate on the so called "the same" membrane?
Our experience has been that RO membranes are not “all the same”. That's why we back up with science the performance of our membranes which are a critical element in the performance of your system, albeit removal of harmful species or your cost to operate your system. Rejected membranes are sold to another, far less demanding market. The difference in price reflects some of our investment to perform the testing. The price difference between an untested and a tested membrane is lost in the savings if you obtain 1 or 2% improvement in rejection as your DI stage(s) life is drastically improved. Even our untested membranes are subjected to a proprietary process which increases their rejection ratio over the units purchased by other vendors from the same supplier. So, those who claim that all membranes from a particular vendor are the same may not be aware of our process by which we routinely see our average rejection increase over non treated units. DI cartridges are one of the highest operation cost factors for your system per gallon of water produced, thus our customers tell us the extra price paid is well worth the return from savings on Di. Others just want the best to take water production quality out of the equation as much as possible from their aquatic environment maintenance equation
and after reading that even if I buy it I STILL dont see why one wouldn't just buy the $150 unit and then buy a spectrapure membrane come replacement time. you'll never make up the difference in DI refills in the 2-3yrs membranes are garaunteed to still be effective and need replacing (provided the carbon blocks are replaced regularly to remove chlorine which will destroy them prematurely).

 

[posiden]

Originally Posted by Stanlalee
http:///forum/post/3151769
here is there explanation. You can buy it if you want to (basically testing to ensure they source only 98% rejection rates. I assure you the source is still the same wether or not the membranes are or arent) just keep in mind we didn't just start using RO units and TDS units yesterday so if you think your going to save money with longer lasting DI filters using spectrapure go ahead and buy it. Its going to take buku DI refills before you start reaping the savings even if you do buy their pitch.
and after reading that even if I buy it I STILL dont see why one wouldn't just buy the $150 unit and then buy a spectrapure membrane come replacement time. you'll never make up the difference in DI refills in the 2-3yrs membranes are garaunteed to still be effective and need replacing (provided the carbon blocks are replaced regularly to remove chlorine which will destroy them prematurely).

So why would one even bother with a RO unit to begin with? Just buy a DI resin unit and be done.

 

[scsinet]

Originally Posted by Posiden
http:///forum/post/3151791
So why would one even bother with a RO unit to begin with? Just buy a DI resin unit and be done.
Because even the "crappy" membranes do most of the heavy lifting, and DI resin does not remove solid particles.
I agree with Stan though... when examining the differences in performance versus the price difference from the various membrane types, I'm not sure that it would be a good justification compared with replacing the DI resin a bit more frequently.
I'm not aware of anyone who has actually done a scientific test on the subject that is NOT in one of the manufacturer's pockets... until then it's more guesswork than anything else.
I also do not believe that the number of stages is simply a marketing tool. It may be if you do not pay attention to what is actually in those stages. The first (and in 5 stage units the first and second) stage is your sediment pre-filter. The more solids you remove from the water before it enters the membrane, the less wear and tear on the membrane, among other things. So it stands to reason to put a 1 micron filter in there. But I've found that my municipal water supply has so much solid matter in it that 1 micron cartridges clog up very quickly. So the solution is to spread out the workload by placing a 5 micron cartridge first, then a 1 micron to catch what the 5 misses.
If you don't have poor quality source water this may not be necessary, but it's hardly just marketing fluff.

 

[thang45]

This is excellent information.
SCSInet, may I ask where did you buy your RO/DI unit for $150?
5 micron for the first stage and 1 micron for the second stage make a lot of sense.
Is it worth it to replace the 35GPH membrane for the seachem unit? Or forget about it and but a new unit with DI?

 

[thang45]

Originally Posted by Stanlalee
http:///forum/post/3151769
here is there explanation. You can buy it if you want to (basically testing to ensure they source only 98% rejection rates. I assure you the source is still the same wether or not the membranes are or arent) just keep in mind we didn't just start using RO units and TDS units yesterday so if you think your going to save money with longer lasting DI filters using spectrapure go ahead and buy it. Its going to take buku DI refills before you start reaping the savings even if you do buy their pitch.
and after reading that even if I buy it I STILL dont see why one wouldn't just buy the $150 unit and then buy a spectrapure membrane come replacement time. you'll never make up the difference in DI refills in the 2-3yrs membranes are garaunteed to still be effective and need replacing (provided the carbon blocks are replaced regularly to remove chlorine which will destroy them prematurely).
If my unit is 35GPD, I can buy the spectrapure membrane and add it to my seachem unit? can I increase 35GPD to 90GPD? also, can I add DI stage to it?

 

[thang45]

I did a quick search on this furom and found these two RO/DI unit.
They are about $139 - $149.
Which model should I go with? I think the two untis above is the one that everybody is talking about.
I just don't understand one thing on their website.
Stage 1) Heavy duty standard industry size 10 Micron Poly Pro sediment filter.
Stage 2) Genuine Gem coconut 5 Micron carbon block *Acid washed.
Stage 3) Genuine Gem coconut 1 Micron carbon block filter *Acid Washed. This removes the remaining chemicals and chlorine. This filter is rated for 9,000 gallons. It's used to strip any remaining chlorine missed by stage 2.
Stage 4) FilmTec TFC membrane 75 GPD (TW301812-75).
Stage 5) One Mixed bed in-line D.I. cartridge 2.5 X 11" mixed bed D.I..
So the last stage 5 is DI? I thought DI is the second last.

 

[scsinet]

We aren't allowed to post links, but you found the one I have.
The stages of an RODI unit appear to the water in the following order:
Sediment > sediment #2 (optional) > carbon > RO > DI
DI always comes last.
YES, you can replace the membrane with a larger capacity one in your existing unit, as long as you replace the flow restrictor as well, they are a matched pair.
And YES, you can add a DI stage.

 

[thang45]

Originally Posted by SCSInet
http:///forum/post/3152037
We aren't allowed to post links, but you found the one I have.
The stages of an RODI unit appear to the water in the following order:
Sediment > sediment #2 (optional) > carbon > RO > DI
DI always comes last.
YES, you can replace the membrane with a larger capacity one in your existing unit, as long as you replace the flow restrictor as well, they are a matched pair.
And YES, you can add a DI stage.
thank you for letting me know about the links.
I have removed both links. Did you get the 149 or the 139?
I'm not too sure if you can even type the name or model, that is why I just type the price. Hopefully you would know what I'm taking about.