RO Unit

[kruger1980]

Hello All

 

Sorry I am not very technical so I will do my best here, I have an RO unit, I belive a 4 stage, its has one filter membrane across the top and the other three below, I have had the unit for a year and not been using it too much so I thought I would replace the filters. I have just changed the sediment filter and the carbon prefilter

but not sure about the membrane on top and the last filter which from what I have read online its a color changing filter to show when it needs replacing, right now the top and bottom have changed to a light color, does this mean I need to change it out? Also how often do I need to change out the top membrane?

 

Many thanks

 

Stuart

[bdare]

Hello All

 

Sorry I am not very technical so I will do my best here, I have an RO unit, I belive a 4 stage, its has one filter membrane across the top and the other three below, I have had the unit for a year and not been using it too much so I thought I would replace the filters. I have just changed the sediment filter and the carbon prefilter

but not sure about the membrane on top and the last filter which from what I have read online its a color changing filter to show when it needs replacing, right now the top and bottom have changed to a light color, does this mean I need to change it out? Also how often do I need to change out the top membrane?

 

Many thanks

 

Stuart

 

Hey Stuart,

 

I'd reccomend picking up a dual TDS monitor for your RO/DI unit. It comes with 2 monitors. I use mine to measure the water after the RO and after the DI. This will allow you to monitor the effectiveness of your RO membrane as well as let you know when your DI resin is exhausted. The monitor will cost you about $35 (including shipping), but save you in the long run both from replacing your filters too soon or too late which could cause you problems with your tank.

 

This is the one I use:

http://www.bulkreefsupply.com/RO/DI-Filter...oduct_info.html

 

Ben

[nanoty]

I use the same one.

[kruger1980]

Thanks guys, thats great, funny enough I do actually have that dual TDS monitor on my RO Unit, so best advice is to watch that meter and change filters when the ppm raises.

 

Currently my PPM are about 5ppm, what sort of numbers are high and should replace the filters?

 

Thank you

 

Stuart

[bdare]

Thanks guys, thats great, funny enough I do actually have that dual TDS monitor on my RO Unit, so best advice is to watch that meter and change filters when the ppm raises.

 

Currently my PPM are about 5ppm, what sort of numbers are high and should replace the filters?

 

Thank you

 

Stuart

 

5ppm is too high for me. I only put 0 TDS water in my tank. More than likely you only need to replace your DI resin. The RO membrane should last for a long time. I get my DI from www.bulkreefsupply.com. You can buy a refillable cartrige and it will be much cheaper in the long run.

 

Ben

[Acerone]

Here's the one that I have

 

http://www.bulkreefsupply.com/p594/TDS-3-H...oduct_info.html

[HecticDialectics]

5ppm is too high for me. I only put 0 TDS water in my tank. More than likely you only need to replace your DI resin. The RO membrane should last for a long time. I get my DI from www.bulkreefsupply.com. You can buy a refillable cartrige and it will be much cheaper in the long run.

 

Ben

 

 

+1

 

Sounds like your DI needs to be changed out.

[dtfleming]

+1. Im on well water that Is hard so I change out my filter more frequently. DI resin will get used pretty quick. Remember the RO membrane and DI lower the TDS. The prefilters help to filter out the sediment before it reaches the RO membrane.

[AZDesertRat]

If you have a dual inline TDS meter, what are the readings?

Generally speaking prefilters and carbons should be changed every 6 months like clockwork. The purpose of these two filters is to protect the more expensive RO membrane which is the workhorse of the system. The RO membrane itself should last 3+ years provided you keep up with the replacements above and you disinfect the system when changing filters.

The DI resin life is entirely dependent on your membranes efficiency, your tap water quality and how much water you make. It may last 100 gallons or it could last 800 gallons. Your TDS meter is the best tool to determine the condition. Fresh DI resin packed properly in a vertical 20 oz cartridge should give you 0 TDS water. When you very first start to see anything other than 0 on a consistent basis, change the DI immediately. DI releases weakly ionized substances even before it is exhausted and a few of these are nitrates, silicates and phosphates, none of which you want in your tanks.

[bdare]

If you have a dual inline TDS meter, what are the readings?

Generally speaking prefilters and carbons should be changed every 6 months like clockwork. The purpose of these two filters is to protect the more expensive RO membrane which is the workhorse of the system. The RO membrane itself should last 3+ years provided you keep up with the replacements above and you disinfect the system when changing filters.

The DI resin life is entirely dependent on your membranes efficiency, your tap water quality and how much water you make. It may last 100 gallons or it could last 800 gallons. Your TDS meter is the best tool to determine the condition. Fresh DI resin packed properly in a vertical 20 oz cartridge should give you 0 TDS water. When you very first start to see anything other than 0 on a consistent basis, change the DI immediately. DI releases weakly ionized substances even before it is exhausted and a few of these are nitrates, silicates and phosphates, none of which you want in your tanks.

 

Very well stated.

[kruger1980]

Thanks very much guys, lots of great information.

 

I have now changed out the DI resin and have 0ppm from my unit, going in is around 120ppm. I will definitly refill my own DI from now on, great idea!

 

I am interested in how to disinfect the system after changing filters, how would one go about doing that?

 

Thank you all once again

 

Stuart

[bdare]

Thanks very much guys, lots of great information.

 

I have now changed out the DI resin and have 0ppm from my unit, going in is around 120ppm. I will definitly refill my own DI from now on, great idea!

 

I am interested in how to disinfect the system after changing filters, how would one go about doing that?

 

Thank you all once again

 

Stuart

 

The 120 in... is that before the RO or after?

[AZDesertRat]

Hopefully the 120 is tap water TDs and not RO TDS .....

To disinfect the system, do so at 6 month intervals when changing the prefilter and carbon block.

1. Shut off the water supply and unscrew the prefilter and carbon housings

2. VERY IMPORTANT- disconnect the 1/4" line that leads from the carbon block up to the RO membrane at the membrane housing end. Stick the end of the line in a bucket or sink.

3. Remove and toss the old filters. Add 3 spoon fulls of regular unscented bleach to the prefilter housing, no more no less. Bleach is a very powerful disinfectant at 50,000 mg/L or parts per million when fresh so more is not better in this situation!

4. Screw the empty housings back on and open the water supply. Fill the housings until you get flow out the disconected line and shut it off for a few minutes. Let the housings si=oak in the bleach solution. An interesting fact here, the Centers for Disease Control (CDC) in Atlanta has determined a free chlorine residual of only 0.5 mg/L or ppm wil kill just about any bacteria or virus known to man with a contact time of 5 minutes. Just a little Tidbit.

5. Run the solution through until the smell has passed, empty the housings, install the new filters and reinstall the housings hand tight plus just a bit. If leaks are a concern a very light coating of food grade silicone grease from the hardware will help lubricate the O-rings.

6. With the 1/4" line still disconnected turn the supply back on and flush all air and nay carbon dust out of the system. Once air and dust have passed hook it back up and you are in business for another 6 months.

 

This process takes maybe 10 minutes total and could save your life. I have personally witnessed people going to the hospital on more than one occasion due to a contaminated RO drinking water system which had not been serviced as recommended.

[kruger1980]

Thank you so much for that break down, I will be doing this from now on, does this need to be done for marine life too or just if Humans drink the RO water? I use my RO Unit for the tank only!

 

The 120 out is the waste water out not the RO water.

 

Going back to the length of time replacing filters does that work for all types of filter? Reason I ask is that I have a filter in my shower head that I bought from Lowes and it works great and I change the filter each 6 months but can't say at the point of changing it that I see any difference in performance, I am throwing good filters away for nothing? Or should I keep them unless I notice a blockage or quality of water changing? In my area there is a strong clorine smell from the water.

 

Thank you again

 

Stuart

[AZDesertRat]

You need to kep up with filter changes regardless if its for humans of fish, you both need good water. Neglecting changes can lead to slime bacteria as well as other visus and bacteria growth inside the housings and on the membrane. This is especially true with low quality high micron rated prefilters and carbons. Prefilters protect the carbon block which is made up of billions of microscopic pores. If the prefilter is rated at a higher micron size than the carbon block (which is the case with most uninformed vendors) then the solids pass through the inexpensive prefilter and plug the pores of the more expensive carbon block and render it useless. The pores adsorb the volatile organics and chlorine.

Once the carbon is fouled it passes chlorine on to the membrane ruining it in a hurry.

 

Do you mean 120 TDS from the waste line or from the tap water IN line? If its from the waste I would venture a guess your tap water TDS is right at 95-100 if your system is set up properly.

 

Shower filters are usually granular activated carbon and probably do little after a few hundred gallons. I'll bet money you can take a chlorine test kit and find evidence of chlorine after just a few showers. They may also another media for radon but again it probably does not have much of an effect after a short time.

RO prefilters get changed for two main reasons, one is when you see evidence of a pressure drop and two is to reduce the possibility of bacteria and virus growth. The carbon gets changed at 6 monthgs since it has a specified useful life depending on how good it is. Granular activated carbon lasts about 300 total gallons (thats 60 good RO/DI gallons and 240 waste gallons since ALL water passes through the carbon on its way to the membrane). Low quality 10 micron carbon blocks may go 1,000 to 1,500 total gallons (again thats 200-300 good RO/DI gallons and 800-1200 waste gallons). High quality 0.5 or 0.6 micron chlorine guzzler carbon blocks can go 20,000 total gallons or 4,000 good gallons and 16,000 waste gallons before being exhausted, that is provided you use a high quality low micron prefilter in front of it so the pores do not plug or foul.

Think about how much water you have made with the filters you have in place now and what condition they might be in. Thats why the 6 month interval, so with quality filters yes there may still be some life left in them but not enough to worry about so just toss them.