Newbie RO/DI question

[cobra617]

Hi folks,
I am new to RO/DI. I bought a Coralife Pure-Flo II (50gpd).
One thing that isn't clear to me.....does it also remove chlorine? I am not sure if I should be using chlorine/chloramine remover.

Thanks.

[Aquarist007]

Originally Posted by cobra617

Hi folks,
I am new to RO/DI. I bought a Coralife Pure-Flo II (50gpd).
One thing that isn't clear to me.....does it also remove chlorine? I am not sure if I should be using chlorine/chloramine remover.

Thanks.

yes it removes chlorine

[cobra617]

Originally Posted by capn_hylinur

yes it removes chlorine

Thanks!

[Aquarist007]

Six Filtration Stages:
1st Stage is a 10" 5 micron PP sediment Pre-Filter removes dirt, sediment, rust and sand particles

2nd Stage GAC (Granular activated carbon) Pre-Filter - removes chlorine, chloramine, odor and chemicals.

3rd Stage is a 10" 1 micron coconut carbon block filter to remove remaining chemicals, pesticides and protect your membrane.

4th Stage is a 100 GPD RO Membrane removes 98% to 99.99% of all chemical and harmful dissolved elements and 99% of all bacteria

5th Stage is a color changing DI (De-Ionized) filter to remove hard water minerals.

6th Stage is a post in-line granular activated carbon filter for final odor and taste.
Note: As installed the filter only has 5 stages. The last 2 stages have been separated. The DI is to produce aquarium water and the post carbon filter is installed to provide drinking water. A t has been installed to provide separate feeds from the RO stage for each application.
Once the initial tank setup is complete. A recommended second DI stage will be added to insure the lowest TDS (Total Dissolved Solids) for makeup water is produced

http://home.comcast.net/~daves-reef/ro_di.htm

[reef_keeper]

Hey cobra, i just bought the same unit as you did, the 4 stage right? do you have any recommendations on setting up the unit or using and servicing the filter?

[Fishamatank]

Get a TDS meter and monitor the water. When you start getting TDS in the water it's time to replace the pre filters and the DI resin.

[reef_keeper]

will i need to replace some more often than others?

[Fishamatank]

When the DI wears out replace the pre filter and carbon block.
If that does not bring the TDS back to zero replace the membrane.
DI resin should last 6 months or so, membrane should last 2 years +/-

[reef_keeper]

thanks i appreciate your help

[Buckeye Hydro]

A good rule of thumb is to replace your sediment filter and carbon block after six months. A more precise way to maximize the useable life of these two filters is to use a pressure gauge to identify when pressure reaching the membrane starts to decline. This is your indication one or both of the filters is beginning to clog.

Also be cognizant of the chlorine capacity of the carbon block. A good 0.5 micron carbon block for example will remove 99% of chlorine from 20,000 gallons of tap water presented at 1 gpm. Some original equipment suppliers commonly provide carbon cartridges rated at 2,000 to 6,000 gallons.

Regarding your RO membrane and DI resin, use your TDS meter to measure, record, and track the TDS (expressed in parts per million) in three places:
1. Tap water
2. After the RO but before the DI
3. After the DI.

The TDS in your tap water will likely range from about 50 ppm to upwards of 1000 parts per million (ppm). Common readings are 100 to 400 ppm. So for sake of discussion, let's say your tap water reads 400 ppm. That means that for every million parts of water, you have 400 parts of dissolved solids. How do we go about getting that TDS reading down to somewhere near zero?

If you do some experimenting with your TDS meter, you'll note that your sediment filter and carbon block filter (collectively called “prefilters”) do very little to remove dissolved solids. So with your tap water at 400 ppm, you can measure the water at the “in” port on your RO housing and you'll see it is still approximately 400 ppm.

The RO membrane is really the workhorse of the system. It removes most of the TDS, some membranes to a greater extent than others. For instance, 100 gpd Filmtec membranes have a rejection rate of 90% (i.e., they reject 90% of the dissolved solids in feed water). So the purified water coming from your 100 gpd membrane would be about 40 ppm (a 90% reduction). Filmtec 75 gpd (and below) membranes produce less purified water (aka “permeate”), but have a higher rejection rate (96 to 98%). The life span of a RO membrane is dependant upon how much water you run through it, and how dirty the water is. Membranes can function well for a year, two years, or more. To test the membrane, measure the total dissolved solids (TDS) in the water coming in to the membrane, and in the purified water (permeate) produced by the membrane. Compare that to the membrane’s advertised rejection rate, and to the same reading you recorded when the membrane was new. Membranes also commonly produce less water as their function declines.

After the RO membrane, water will flow to your DI housing. DI resin in good condition will reduce the 40 ppm water down to 0 or 1 ppm. When the DI output starts creeping up from 0 or 1 ppm, you know that your resin needs to be replaced. Sometimes people complain that their DI resin didn't last very long. Often the culprit is a malfunctioning RO membrane sending the DI resin “dirty” water. This will exhaust the resin quicker than would otherwise have been the case. Sometimes the problem is poor quality resin – remember that all resins are not created equal!

Russ