Dow Chemical

100 GPD Reverse Osmosis Membrane - DOW Filmtec

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The DuPont (formerly Dow Chemical) Filmtec 100 GPD membrane features a 98% rejection rate at 50 PSI which makes it the most commonly used 100 GPD membrane used in the aquarium industry. If you require slightly faster water production and have good water pressure this is one of the better options.


TIP -Brand new membranes will have a slight coating on them to help preserve the membrane until it is ready for use.  It is recommended to discard all water that is produced by the new membrane for the first hour of operation. 


For Product Data Sheet Click Here


DuPont Filmtec 100 GPD TW30-1812-100HR Membrane Specs:

  • 100 Gallons Per Day
  • ANSI/NSF 58 listed for material safety.
  • Dimensions: 1.83" W X 11.75" L
  • Stabilized Salt Rejection (%): 98.0
  • Permeate Flow* gpd @ 50 psi: 100


*Permeate flow specifications are based on 250 mg/L NaCl solution at 50 psi (3.4 bar) inlet pressure, 77°F (25°C), 15% recovery after 24 hours. Individual element flux may vary ±20%.


Membrane Replacement Instructions

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Product Questions

How do you know when this needs replaced?
Question by: Roy Allen on Oct 14, 2023, 3:41 PM
Hey there,
Thank you for reaching out to us. We recommend replacement every 2 to 3 years. Please let me know if you need anything further.
Answer by: Thomas Wofle (BRS Staff) on Oct 25, 2023, 9:59 AM
will this membrane fit my mpdi 90 system
Question by: derrin chango on Jul 15, 2022, 10:28 AM
That is a great question. This RO membrane will fit any standard size RO membrane housing. Be sure to check out your flow restrictor sizing to be sure it will still match this RO membrane. 800ml/min is recommended for the 100 GPD membrane. We do sell flush valve flow restrictors to replace your stock one if they do not match for this membrane.


Answer by: Rick Pucciarella (BRS Staff) on Jul 15, 2022, 11:37 AM
What pressure should I set my booster pump at for this membrane? 50psi as stated in the above data? Or?
Question by: Dane Brillhart on Nov 2, 2019, 5:15 PM
Hey there-

Great question! Normally we recommend anywhere from 50-80 PSI is a good range, with my preferred PSI being around 60.

Take care! c:
Answer by: Brad Ohmann on Nov 3, 2019, 2:50 PM
How often do you change?
Question by: Arthur Rundle on Jan 6, 2019, 1:41 PM
Thank you for reaching out to Bulk Reef Supply! That is a great question. We recommend your membrane be changed once every 3-5 years or so in most cases. I hope this qas helpful!
Answer by: Ashley on Jan 7, 2019, 11:57 AM
Will the dow 100g membrane fit my aqua fx 100gpd unit
Question by: kurt rauber on Jan 29, 2018, 6:10 PM
Yes, it should be a direct replacement. Just as long as your membrane housing looking like the ones we use, the membranes should be interchangeable.
Answer by: Charlie on Jan 30, 2018, 4:50 AM
What modification/s (if any) to my system, 6 stage WS+, do I need to make if I replace both 75gpd memebranes with 100gpd.

My system holds a steady pressure of 58-60 psi. Incoming TDS is light at only 120-135.
Question by: Aaron Wasson on Sep 11, 2017, 6:29 PM
To change up to 100gpd membranes you would just need to replace both of the membranes and the flow restrictor. Other than that the modifications should be almost non-existent.
Answer by: Charlie on Sep 13, 2017, 2:43 PM
will this work in your 75gallon system
Question by: Corey Bodey on Nov 6, 2016, 7:23 PM
Hey there, thanks for reaching out to us! These membranes will work in our systems, however you would need to change the flow restrictor. Also, the 100 GPD membranes will not have the same 99%-98% rejection rates as the 75 GPD membranes. You may notice higher TDS after the RO membrane, which can result in faster DI Resin consumption rates.

Answer by: Randy on Nov 7, 2016, 5:37 PM
Can this 100 GPD membrane be used in other RO system? Such as the water general ro6100DINT? Thanks!
Question by: Montana Lynn on May 22, 2016, 8:24 PM
Great question! Our RO membranes our standard 10" membranes, and should work with most 3rd party units. That said, compatibility cannot be guaranteed.
Answer by: Carter on May 25, 2016, 2:53 PM
Your 100 GPD filter is listed as TW30-1812-100HP. Dows sight has it listed as TW30-1812-100HR. What is the difference between the two?
Question by: Henry Bosman on Feb 2, 2016, 12:40 PM
Great question!
There is no difference in the membrane. It appears as if the HR vs HP may be a typo on our side. Feel free to let us know if you have any further questions!
Answer by: Connor on Feb 24, 2016, 4:34 PM