Recommended Micron Ratings

[FirstContact]

Hi,

I'm running a double RO membrane on my unit and have about 60 psi. I typically use a 1.0 micron sediment and 0.5 micron carbon filter from MD. Is that still what you recommend, or should I be using 0.5 sediment and 0.5 carbon? I typically would use 2 75 gpd membranes, but right now my first is a 100gpd Puratek and the second is 75gpd DOW. My combined TDS membrane output is about 15, so I think one of the membranes is blown. My state water service does not use chloramines, so I am confused why one of the membranes would have blown so prematurely. I just set up new filters and membranes and switched to double membranes last August or so. I change pre-filters every six months and my system is 220g plus 70g in 2 QT tanks.

Also, I need a new in line TDS meter. I was thinking about using a triple and putting one after each membrane output and one after my first DI stage.

Appreciate any advice or suggestions.
Thoughts? Advice?

 

[MarineDepot]

Hi,

I'm running a double RO membrane on my unit and have about 60 psi. I typically use a 1.0 micron sediment and 0.5 micron carbon filter from MD. Is that still what you recommend, or should I be using 0.5 sediment and 0.5 carbon? I typically would use 2 75 gpd membranes, but right now my first is a 100gpd Puratek and the second is 75gpd DOW. My combined TDS membrane output is about 15, so I think one of the membranes is blown. My state water service does not use chloramines, so I am confused why one of the membranes would have blown so prematurely. I just set up new filters and membranes and switched to double membranes last August or so. I change pre-filters every six months and my system is 220g plus 70g in 2 QT tanks.

Also, I need a new in line TDS meter. I was thinking about using a triple and putting one after each membrane output and one after my first DI stage.

Appreciate any advice or suggestions.
Thoughts? Advice?

You may not be getting the purest water possible because of the input water pressure. The 60 PSI is sufficient for the membranes to function but they will function best with consistently higher pressure not to exceed 90 PSI based on my understanding. Because you have dual membranes, consistent pressure is all that more important to ensure optimal performance of the membranes.

I suggest you look into a booster pump for your system, this is the best way to operate a dual membrane unit because a booster pump will provide your membranes with optimal pressure each and every time ensuring your membranes are always producing filtered water at the best possible rate. The AquaticLife Smart Buddie pump is a great choice and is super easy to install. Plus, it features an automatic flush system which will further extend the life of your membranes and ensure the best possible performance at all times. I installed one on my personal RO/DI system and wish I would have done it years ago. I get filtered RO/DI water faster than ever before and I get a far better ratio of waste to product water.

AquaticLife Smart Buddie Booster Pump: http://mdshop.us/BoosterBuddy

A membrane can quickly become exhausted for various reasons and here are some common reasons why this might happen; pre-filters not replaced correctly/on-time, accidental warm water feed into membrane, lack of proper flushing before and after each use, letting the membrane dry out in between uses, and/or chloramines getting through the pre-filters and into the membrane.

I usually consider replacing my membrane when the product water hits 10 ppm with the TDS meter. I always monitor input water, RO water and then finally the DI water so the triple inline TDS meter is a great choice for quick on-demand monitoring of your RO filters. Using a TDS meter on each of the membranes individually will help you to determine exactly which one is not performing.

For the micron ratings on your sediment and carbon; personally I use the 0.5 micron sediment and then a 0.5 or 1 micron carbon block filter. The sediment stage micron rating should always be equal too or smaller than the next filter immediately inline. In situations were the feed water may contain higher sediments than normal, dual sediment filters can be employed by adding an additional canister to your system. In situations in which chloramines are always a threat, using dual carbon filters is recommended.

Feel free to ping us anytime if you need further assistance.

-Robert @ MD

 

[FirstContact]

Thanks Robert this is exactly the information I was looking for and it will help me greatly with my purchases!

Looking forward to an Easter sale!

 

[FirstContact]

Hi Robert!

Okay! Did some testing. Tap water is 175 ppm. First membrane a 100gpd Puratek is producing 2 ppm and the second membrane a 75gpd dow is producing 35 ppm. So, I'm getting a better than 98% rejection rate on the first membrane and a n 80% rejection rate on the second membrane. The second membrane is definitely blown. Not sure if it's because of the membrane age, or if it was in my single set up and I ran the pre-filters too long, or if it's just the tandem set up that wore it out. I'll be taking your advice above when I make my purchases.

Thanks again!

 

[MarineDepot]

Hi Robert!

Okay! Did some testing. Tap water is 175 ppm. First membrane a 100gpd Puratek is producing 2 ppm and the second membrane a 75gpd dow is producing 35 ppm. So, I'm getting a better than 98% rejection rate on the first membrane and a n 80% rejection rate on the second membrane. The second membrane is definitely blown. Not sure if it's because of the membrane age, or if it was in my single set up and I ran the pre-filters too long, or if it's just the tandem set up that wore it out. I'll be taking your advice above when I make my purchases.

Thanks again!

Always happy to help @FirstContact and thanks for choosing Marine Depot. Feel free to ping me anytime if you need help with products or have questions. [email protected].

-Robert @ MD

 

[FirstContact]

Hi Robert,

No Easter sale, but I bought my RO supplies anyway! I notice when the product water from my RO membranes is diverted away from the DI resin the TDS drops significantly than when it flows in-line towards the DI resin. I can’t explain this, can you?

Thank you,
FirstContact
Gary