ro/di

rmw4547 · 03/19/2008, 12:51 PM

at what tds do change your membrain?

syded70 · 03/19/2008, 01:51 PM

THe membrane lasts for years unless you have extremely bad water. You want to change out your carbon filters out about every 6 months and the DI when you start getting 1 ppm.

aquaman67 · 03/19/2008, 02:18 PM

Take the line that goes from the RO membrane into the DI loose.

Test that water.

Now test your tap water.

You'll want at least 95% effeciency.

Let's say your tap water is 300 TDS.

The RO only (before DI) is 6 TDS

That's 98 % effecient.

300 - 6 = 294

294 / 300 = .98

.98 X 100 = 98

If you're getting less that 95% I'd get a new membrane.

As a side note, if you're using a e-bay RO/DI you might not get 95% from a new unit. If you do the math as I did above on the claims on their own site it says that with tap water of 300 you'll get RO only water of about 20. That's only 93% effecient from a new membrane. Kent and other name brands are at 98 - 99 % when new.

cathoai · 03/19/2008, 07:31 PM

A newbie question...can you use the kent membrane on the ebay unit?

aquaman67 · 03/20/2008, 03:06 PM

You can change membranes. If it's rated at the same gallons per day, then it's just a direct swap.

If you change to a different gallons per day then you have to replace the restrictor too. The restrictor is in a small rubbery thing in the waste line. If you talk with the RO/DI sponsors on Reef Central, they can help you get everything you need!

AZDesertRat · 03/20/2008, 08:36 PM

If you are going to spend money on a new membrane get the Spectrapure Select hand tested membrane. It is the only membrane on the market that is individually hand tested and guaranteed to be 98+% efficient. This is a significant savings when you consider for every 2% you increase the membranes efficiency you DOUBLE the life of your DI resin. It does not take long to recoup the cost difference.

cathoai · 03/20/2008, 10:56 PM

where can I get the membrane?

AZDesertRat · 03/20/2008, 11:07 PM

http://www.spectrapure.com/St_replac_p3.htm

aquaman67 · 03/21/2008, 08:10 AM

Quote:

Originally posted by AZDesertRat
the Spectrapure Select hand tested membrane. It is the only membrane on the market that is individually hand tested and guaranteed to be 98+% efficient.

I read somewhere (I can't find it) that the Kent Hi-S membranes are also "cherry picked" or tested too.

There was a list of specific ions and their rejection rate on that site too. I wish I'd bookmarked it.

03/19/2008, 12:51 PM	#1
rmw4547 Registered Member Join Date: Aug 2007 Location: ny Posts: 119	ro/di at what tds do change your membrain?

03/19/2008, 01:51 PM	#2
syded70 Registered Member Join Date: Sep 2005 Location: Outside of a glass box full of water Posts: 112	THe membrane lasts for years unless you have extremely bad water. You want to change out your carbon filters out about every 6 months and the DI when you start getting 1 ppm. __________________ 2 fish are swimming along. 1 of the fish runs into a stone wall and says "dam". Current Tank Info: 180 Gallon Drilled Tank with 55 Gallon Sump The Sump has 1/3 DSB w/ pleneum. I also have an old wet/dry sump used for a fuge where I house sps, lps, cheato. This is under a 96 Watt 20" PC, Coralife.

03/19/2008, 02:18 PM	#3
aquaman67 Registered Member Join Date: Feb 2002 Location: Tennessee Posts: 7,629	Take the line that goes from the RO membrane into the DI loose. Test that water. Now test your tap water. You'll want at least 95% effeciency. Let's say your tap water is 300 TDS. The RO only (before DI) is 6 TDS That's 98 % effecient. 300 - 6 = 294 294 / 300 = .98 .98 X 100 = 98 If you're getting less that 95% I'd get a new membrane. As a side note, if you're using a e-bay RO/DI you might not get 95% from a new unit. If you do the math as I did above on the claims on their own site it says that with tap water of 300 you'll get RO only water of about 20. That's only 93% effecient from a new membrane. Kent and other name brands are at 98 - 99 % when new.

03/19/2008, 07:31 PM	#4
cathoai Registered Member Join Date: Jul 2007 Location: Elk Grove Posts: 274	A newbie question...can you use the kent membrane on the ebay unit?

03/20/2008, 03:06 PM	#5
aquaman67 Registered Member Join Date: Feb 2002 Location: Tennessee Posts: 7,629	You can change membranes. If it's rated at the same gallons per day, then it's just a direct swap. If you change to a different gallons per day then you have to replace the restrictor too. The restrictor is in a small rubbery thing in the waste line. If you talk with the RO/DI sponsors on Reef Central, they can help you get everything you need!

03/20/2008, 08:36 PM	#6
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	If you are going to spend money on a new membrane get the Spectrapure Select hand tested membrane. It is the only membrane on the market that is individually hand tested and guaranteed to be 98+% efficient. This is a significant savings when you consider for every 2% you increase the membranes efficiency you DOUBLE the life of your DI resin. It does not take long to recoup the cost difference.

03/20/2008, 10:56 PM	#7
cathoai Registered Member Join Date: Jul 2007 Location: Elk Grove Posts: 274	where can I get the membrane?

03/20/2008, 11:07 PM	#8
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	http://www.spectrapure.com/St_replac_p3.htm