RO/DI Overhaul

ellisz · 06/01/2007, 08:35 AM

I am in process of upgrading my RO/DI unit. It is over 3 years old. I recently bought clear canisters and a dual DI unit. The RO unit uses a 5 micron sediment filter, activated carbon filter and a 1 micron coconut carbon block. The membrane is a 100 gpd unit.

I plan to get a 75 GPD Filmtec membrane as the current one is getting older and I would like something with a better rejection rate as I have to make a lot more water now. Do I just need to replace the membrane and the flow restrictor to make this work?

I have seen some sites that use different filters for different stages. Anything wrong with what I am using?

Also, what does everyone do to make sure there water is pure? I have the color changing DI, clear canisters to watch the sediment filter, dual TDS meter to monitor incoming and outgoing water and I test for PO4 on the output water on occasion. Anything else?

For all intensive purposes, the unit I have has done well. I have upgraded a few things here and there. I have a 300 gal system now so I want to make sure the water is not feeding any algae!

Thanks

ellisz · 06/01/2007, 01:44 PM

Going home bump

ellisz · 06/04/2007, 07:54 AM

Monday bump

blmeier7 · 06/04/2007, 08:35 AM

Yes, you should be good going to a 75gpd membrane as long as you match with the correct flow restrictor.

Your prefilter selection should be just fine unless you have really bad tapwater (700+ tds, very high chlorine, etc)

Your testing should be adequate. Some people test for chlorine after the pre's/before the membrane.

1SickReefer · 06/04/2007, 08:46 AM

I have done the same to my ebay unit, I replaced all the guts with Specrapure 1m sediment, 2x 1m carbon and a 75 dow membrane with a 75gpd fr.

I ditch the hollow DI tub and added a spectrapure MaxCap DI and could never be happier.

ellisz · 06/04/2007, 09:10 AM

Great. Just wanted to make sure I am making the right move.

Thanks

AZDesertRat · 06/04/2007, 09:34 AM

Scrap the granular carbon, it will grind to dust and plug the carbon block downstream. You really only need one carbon block if you stick with a 0.5 to 1.0 micron size. I prefer the 0.5 as its rated for 20,000 gallons of normally chlorinated water.
To check for water purity the best thing you can buy is the HM Digital COM-100 handheld TDS meter, it is easily 10x more accurate on the low end than any other hobbyist grade TDS meter on the market. I have two of the dual inline meters but only use them as a guide since they are not temperature compensated and can be off quite a bit if your water temp and air temp are not exactly the same (which they never are).

ellisz · 06/14/2007, 05:24 AM

So you are saying to scrap the activated carbon filter? Any recommendation on a different type of filter?

BTW, I pulled my old membrane last night and replaced it with a 75 gpd Filmtec membrane. The 100 gpd unit I had been suing was an applied membrane. These are supposed to be good to, right? The flow restrictor I had was a little different than the new one I got with my order. I ended up removing the old one and the new one was an inline so it all worked out in the end.

AZDesertRat · 06/14/2007, 08:14 AM

You can go with graduated prefilter sizes as in a 10 or 5 micron up front followed by a 1.0 or 0.5 second then a single 0.5 micron carbon block. Or you can stick with two carbon blocks for grater chlorine capacity, so something like a 1.0 or 0.5 micron prefilter, a 1.0 micron carbon block, a 0.5 micron carbon block then the membrane?
Its up to you. Most areas don't need multiple carbons since a single 0.5 micron block is good for 20,000 gallons of normally chlorinated water. Granular carbon can be shot in as little as 300 to 1,000 gallons.
The Applied and the Dow are very similar, the Dow probably gets the nod though as it is a little bit more efficient.

06/01/2007, 08:35 AM	#1
ellisz Premium Member Join Date: May 2004 Location: Indiana Posts: 568	RO/DI Overhaul I am in process of upgrading my RO/DI unit. It is over 3 years old. I recently bought clear canisters and a dual DI unit. The RO unit uses a 5 micron sediment filter, activated carbon filter and a 1 micron coconut carbon block. The membrane is a 100 gpd unit. I plan to get a 75 GPD Filmtec membrane as the current one is getting older and I would like something with a better rejection rate as I have to make a lot more water now. Do I just need to replace the membrane and the flow restrictor to make this work? I have seen some sites that use different filters for different stages. Anything wrong with what I am using? Also, what does everyone do to make sure there water is pure? I have the color changing DI, clear canisters to watch the sediment filter, dual TDS meter to monitor incoming and outgoing water and I test for PO4 on the output water on occasion. Anything else? For all intensive purposes, the unit I have has done well. I have upgraded a few things here and there. I have a 300 gal system now so I want to make sure the water is not feeding any algae! Thanks

06/01/2007, 01:44 PM	#2
ellisz Premium Member Join Date: May 2004 Location: Indiana Posts: 568	Going home bump __________________ If you are in S. Indiana or Louisville Check out LMAS.org Current Tank Info: 180 Reef, 100 Frag

06/04/2007, 07:54 AM	#3
ellisz Premium Member Join Date: May 2004 Location: Indiana Posts: 568	Monday bump __________________ If you are in S. Indiana or Louisville Check out LMAS.org Current Tank Info: 180 Reef, 100 Frag

06/04/2007, 09:10 AM	#6
ellisz Premium Member Join Date: May 2004 Location: Indiana Posts: 568	Great. Just wanted to make sure I am making the right move. Thanks __________________ If you are in S. Indiana or Louisville Check out LMAS.org Current Tank Info: 180 Reef, 100 Frag

06/14/2007, 05:24 AM	#8
ellisz Premium Member Join Date: May 2004 Location: Indiana Posts: 568	So you are saying to scrap the activated carbon filter? Any recommendation on a different type of filter? BTW, I pulled my old membrane last night and replaced it with a 75 gpd Filmtec membrane. The 100 gpd unit I had been suing was an applied membrane. These are supposed to be good to, right? The flow restrictor I had was a little different than the new one I got with my order. I ended up removing the old one and the new one was an inline so it all worked out in the end. __________________ If you are in S. Indiana or Louisville Check out LMAS.org Current Tank Info: 180 Reef, 100 Frag

06/04/2007, 08:35 AM	#4
blmeier7 Registered Member Join Date: Feb 2005 Location: Amarillo, TX Posts: 433	Yes, you should be good going to a 75gpd membrane as long as you match with the correct flow restrictor. Your prefilter selection should be just fine unless you have really bad tapwater (700+ tds, very high chlorine, etc) Your testing should be adequate. Some people test for chlorine after the pre's/before the membrane.

06/04/2007, 08:46 AM	#5
1SickReefer Registered Member Join Date: Aug 2005 Location: Perryville, MD Posts: 1,048	I have done the same to my ebay unit, I replaced all the guts with Specrapure 1m sediment, 2x 1m carbon and a 75 dow membrane with a 75gpd fr. I ditch the hollow DI tub and added a spectrapure MaxCap DI and could never be happier.

06/04/2007, 09:34 AM	#7
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Scrap the granular carbon, it will grind to dust and plug the carbon block downstream. You really only need one carbon block if you stick with a 0.5 to 1.0 micron size. I prefer the 0.5 as its rated for 20,000 gallons of normally chlorinated water. To check for water purity the best thing you can buy is the HM Digital COM-100 handheld TDS meter, it is easily 10x more accurate on the low end than any other hobbyist grade TDS meter on the market. I have two of the dual inline meters but only use them as a guide since they are not temperature compensated and can be off quite a bit if your water temp and air temp are not exactly the same (which they never are).

06/14/2007, 08:14 AM	#9
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	You can go with graduated prefilter sizes as in a 10 or 5 micron up front followed by a 1.0 or 0.5 second then a single 0.5 micron carbon block. Or you can stick with two carbon blocks for grater chlorine capacity, so something like a 1.0 or 0.5 micron prefilter, a 1.0 micron carbon block, a 0.5 micron carbon block then the membrane? Its up to you. Most areas don't need multiple carbons since a single 0.5 micron block is good for 20,000 gallons of normally chlorinated water. Granular carbon can be shot in as little as 300 to 1,000 gallons. The Applied and the Dow are very similar, the Dow probably gets the nod though as it is a little bit more efficient.