instrance
New member
http://cgi.ebay.com/New-Reef-6st-10...1QQihZ002QQcategoryZ20684QQrdZ1QQcmdZViewItem
What do you think of this one?
What do you think of this one?
Ro/Di System
- Thread starter instrance
- Start date
instrance
New member
http://cgi.ebay.com/125-GPD-Reverse...emZ160070224283QQcategoryZ20684QQcmdZViewItem
This one looks a lot better. What do you think?
This one looks a lot better. What do you think?
jeffbrig
Premium Member
On the first one:
That tiny DI cartridge will be used up VERY quickly, especially with a 100gpd membrane that's probably only 90% effective. The carbon post-filter is also unnecessary, and possibly undesirable for the reef tank.
On the 2nd:
What's different here, an extra DI cartridge? And what's the rejection ratio on a "125gpd" membrane (see below)? The pressure tank may come in handy if you want to use it for drinking water.
Regarding DI: a full size vertical DI cartridge can soak up ~5-6000 grains of tds. If your RO membrane puts out 1ppm water, that's good for 5-6000 gallons. At 10ppm, that's 5-600g. At 20ppm, that's only 250-300g. This is why RO rejection ratio is so important. With a good membrane that produces low tds, you signficiantly extend your DI life. My typhoonIII unit spits out 0-1ppm water from the RO stage, and I have yet to change my DI cartridge - after 2 years and probably 3000g+ of water produced.
The tiny DI cartridges on these units are MUCH lower in capacity, and I'd bet money that even two is still smaller than a full size vertical DI. You would probably be replacing DI resin regularly. I'd also be wary of the brand-name-not-given RO membranes. The rejection ratio of the membrane is extremely important to know. I would generally recommend a Dow Filmtec 75gpd membrane, because it gives a higher rejection ratio, approaching 98%. The difference between 90% and 98% is 5X the DI life. The cost of replacing DI resin can quickly eat up the savings of buying a "bargain" unit.
Also, more expensive units offer pressure gauges, bypass valves, tds meters, etc., all of which can be very useful to have. Also, whatever you get, make sure you have an auto-shutoff valve, and get a float valve to mount in whatever container you plan to fill when you make water.
Hope that helps, it's kind of rambling....
That tiny DI cartridge will be used up VERY quickly, especially with a 100gpd membrane that's probably only 90% effective. The carbon post-filter is also unnecessary, and possibly undesirable for the reef tank.
On the 2nd:
What's different here, an extra DI cartridge? And what's the rejection ratio on a "125gpd" membrane (see below)? The pressure tank may come in handy if you want to use it for drinking water.
Regarding DI: a full size vertical DI cartridge can soak up ~5-6000 grains of tds. If your RO membrane puts out 1ppm water, that's good for 5-6000 gallons. At 10ppm, that's 5-600g. At 20ppm, that's only 250-300g. This is why RO rejection ratio is so important. With a good membrane that produces low tds, you signficiantly extend your DI life. My typhoonIII unit spits out 0-1ppm water from the RO stage, and I have yet to change my DI cartridge - after 2 years and probably 3000g+ of water produced.
The tiny DI cartridges on these units are MUCH lower in capacity, and I'd bet money that even two is still smaller than a full size vertical DI. You would probably be replacing DI resin regularly. I'd also be wary of the brand-name-not-given RO membranes. The rejection ratio of the membrane is extremely important to know. I would generally recommend a Dow Filmtec 75gpd membrane, because it gives a higher rejection ratio, approaching 98%. The difference between 90% and 98% is 5X the DI life. The cost of replacing DI resin can quickly eat up the savings of buying a "bargain" unit.
Also, more expensive units offer pressure gauges, bypass valves, tds meters, etc., all of which can be very useful to have. Also, whatever you get, make sure you have an auto-shutoff valve, and get a float valve to mount in whatever container you plan to fill when you make water.
Hope that helps, it's kind of rambling....
instrance
New member
Just bought this unit. http://cgi.ebay.com/WaterGeneral-RO...0756QQtcZphotoQQcmdZViewItem#ebayphotohosting
Had them change the membrane to Dow Filmtec 75gpd membrane. Thanks for all the help.
Had them change the membrane to Dow Filmtec 75gpd membrane. Thanks for all the help.
loyalrogue
New member
I read thru his stats, and it states that they normally use a GE Desal membrane which they claim is even better than the Dow Filmtec.
Anyone have any info to back this up or shoot it down?
I'm thinking of getting this same RO/DI unit.
