JUSTINSREEF
Community Member
Just wondering what is a good brand without killing my wallet..and how many stages do i need 3,4, or 5
Ro/di water system
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Hyprviperx
Well-Known Member
i think you can get a 4 stage coralife for pretty cheap... youll want to make sure that it says RO/DI the fewer stages the better the chance it doenst contain a DI unit. its around 150, you can get it w/o the DI and its 126 but the ad on DI is $% so its cheaper to go ahead and buy it with the 4th stage. heres a pretty good deal Coralife Pure-Flo II 50 gallon per day 4 stage RO System,: Aquatic Connection Live FWIW this is probably going to be the one i buy in the near future.:bigsmile:
Spectrapure hands down, there is no comparison.
$120 complete with a 90 GPD high rejection rate specially treated and batch tested RO membrane, 0.5 micron absolute rated sediment filter, 0.5 micron 20,000 gallon carbon block, a full size 20 oz vertical refillable filled with custom blended reef specific SilicaBuster DI resin, an inline pressure gauge and a capilly tube flow restictor you adjust your self for an exact waste ratio just for starters.
You won't find any better anywhere.
MAXPURE MPDI SYSTEM
Untitled Document
$120 complete with a 90 GPD high rejection rate specially treated and batch tested RO membrane, 0.5 micron absolute rated sediment filter, 0.5 micron 20,000 gallon carbon block, a full size 20 oz vertical refillable filled with custom blended reef specific SilicaBuster DI resin, an inline pressure gauge and a capilly tube flow restictor you adjust your self for an exact waste ratio just for starters.
You won't find any better anywhere.
MAXPURE MPDI SYSTEM
Untitled Document
Forget the word "stages" even exists. It was a sales gimmic started by the ebay vendors to makea crappy system sound like teh best thing since sliced bread. 6 or 7 junk stages do not equal 4 good stages and in fact are detrimental since each "stage" has an associated pressure loss which reduces the efficiency of the system.
1. One sediment filter and the lower the micron rating the better it protects the downstream carbon block and RO membrane. Absolute rated is better than nominal rated.
2. One carbon block, not two or more. One low micron carbon block is more than suuficient for up to 20,000 gallons of normally chlorinated or chloraminated tap water, no more no less.
3. One RO membrane, the most popular choiceis the Dow Filmtec 75 GPD which is what Spectrapurestarts with for their membranes then improves upon them then tests them for both GPD and rejection rate.
4. One or in extreme cases Two DI filters.
Thats it 4 stages is more than adequate for 99% of all users and if you want an additional "stage" a second DI filter is a good investment.
1. One sediment filter and the lower the micron rating the better it protects the downstream carbon block and RO membrane. Absolute rated is better than nominal rated.
2. One carbon block, not two or more. One low micron carbon block is more than suuficient for up to 20,000 gallons of normally chlorinated or chloraminated tap water, no more no less.
3. One RO membrane, the most popular choiceis the Dow Filmtec 75 GPD which is what Spectrapurestarts with for their membranes then improves upon them then tests them for both GPD and rejection rate.
4. One or in extreme cases Two DI filters.
Thats it 4 stages is more than adequate for 99% of all users and if you want an additional "stage" a second DI filter is a good investment.
OP
OP
JUSTINSREEF
Community Member
thanks for all the info i have a ro/di unit on the way and for now i am going to use distilled water best i can do.. on the distilled water do you have to use the water conditioner/dechlorinator
No, no conditioners or additives are needed. The chlorine has been removed by carbon before the distillation process.
CalmSeasQuest
Well-Known Member
I'm curious about your recommendation of using a single membrane. I just ordered a 2nd 75GPD Dow membrane with the primary goal being the reduction of waste water and secondarily increasing RO production. I run the RO/DI at ~100PSI. Do you not beleive a 2nd membrane to be a good addition?
If you have over 65 psi then a second membrane will increase production.
Dual membranes ARE NOT WATE RSAVING DEVICES!
There are a few, less informed vendors who promote dual membrane systems as a low waste system but this is 100% false advertising and does not work.
Membranes must be flushed, regardless if its one membrane or ten membranes and the waste ratio needs to stay at close to 4:1 even with two membranes.
Think about how it works for a minute; You are taking the concentrated waste from the first membrane, which will be 20 to 25% higher TDS than the tapp water was to begin with and running it through a second membrane. The second membrane will be running as a lower pressure also since has been through the first membrane so will not be as efficient either so it is at more than one disadvantage already.
If you reduce the waste ratio to less than 4:1, the membranes will fail prematurely. Every membrane manufacturere in the world wil confirm this, they and older vendors such as Spectrapure and AWI, both in business over 25 years, tried this decades ago and dismissed it since it is not in the consumers best interest. They won't sell you something that does not work long term.
I used to have a dual membrane MaxCap system with a 90 GPD and a hand tested 150 GPD that produced close to 250 GPD at 68 psiand it worked well, at 4:1 waste ratio. DO NOT reduce the waste to less than that is you expect your system to work wel and las tany length of time.
Dual membranes ARE NOT WATE RSAVING DEVICES!
There are a few, less informed vendors who promote dual membrane systems as a low waste system but this is 100% false advertising and does not work.
Membranes must be flushed, regardless if its one membrane or ten membranes and the waste ratio needs to stay at close to 4:1 even with two membranes.
Think about how it works for a minute; You are taking the concentrated waste from the first membrane, which will be 20 to 25% higher TDS than the tapp water was to begin with and running it through a second membrane. The second membrane will be running as a lower pressure also since has been through the first membrane so will not be as efficient either so it is at more than one disadvantage already.
If you reduce the waste ratio to less than 4:1, the membranes will fail prematurely. Every membrane manufacturere in the world wil confirm this, they and older vendors such as Spectrapure and AWI, both in business over 25 years, tried this decades ago and dismissed it since it is not in the consumers best interest. They won't sell you something that does not work long term.
I used to have a dual membrane MaxCap system with a 90 GPD and a hand tested 150 GPD that produced close to 250 GPD at 68 psiand it worked well, at 4:1 waste ratio. DO NOT reduce the waste to less than that is you expect your system to work wel and las tany length of time.
CalmSeasQuest
Well-Known Member
Thanks for your reply AZD, but I'm a bit confused. With the additional Filmtec membrane in a system with a 100PSI at the first membrane - Even with the pressure drop across the first membrane, I'm "assuming" there will be more than enough pressure to efficiently operate the 2nd membrane. As is, I have ~1TDS post RO and into the DI.
Even with the higher TDS into the second membrane, won't this result is less waste water? (perhaps at a slight loss in DI capacity if the product water from the 2nd membrane is slightly higher TDS?)
I don't really need the higher production rate (I viewed it as a bonus) If there is no decrease in wasted water, I may not bother with the upgrade.
Even with the higher TDS into the second membrane, won't this result is less waste water? (perhaps at a slight loss in DI capacity if the product water from the 2nd membrane is slightly higher TDS?)
I don't really need the higher production rate (I viewed it as a bonus) If there is no decrease in wasted water, I may not bother with the upgrade.
Yes at 100 psi on the first, the second membrane should be operatiing quite well, provided you keep it flushed.
If you increase the overall GPD to 150 GPD, then you change the flow restrictor to reflect that 150 GPD so would waste 4:1 or 4x150= 600 GPD.
The waste from the first goes into the second so tere is only one restrictor on the outlet of the second that needs to account for both.
Here is a diagram of how you configure the system:
http://www.spectrapure.com/huds/DUAL.pdf
Note how the black concentrate or waste line connects from the first to the second without a restrictor installed.
A dual membrane system is only a way to increase production, never a way to save water and they were never intended to do so.
If you increase the overall GPD to 150 GPD, then you change the flow restrictor to reflect that 150 GPD so would waste 4:1 or 4x150= 600 GPD.
The waste from the first goes into the second so tere is only one restrictor on the outlet of the second that needs to account for both.
Here is a diagram of how you configure the system:
http://www.spectrapure.com/huds/DUAL.pdf
Note how the black concentrate or waste line connects from the first to the second without a restrictor installed.
A dual membrane system is only a way to increase production, never a way to save water and they were never intended to do so.
