Go Back   Aquarium Advice - Aquarium Forum Community > Saltwater and Reef > Saltwater Reef Aquaria
Click Here to Login

Join Aquarium Advice Today
Thread Tools Search this Thread Display Modes
Please support our sponsors and let them know you heard about them on AquariumAdvice.com
Old 11-19-2005, 11:19 AM   #1
Aquarium Advice Activist
Join Date: Oct 2005
Location: Victoria, BC
Posts: 113
Understanding RO/DI systems

This got started on another thread but needed a new subject to attract more input...

I'm just turning around to getting a RO/DI unit and don't know an awful lot about them, which makes selecting one rather difficult. What do I look for? I don't know anything about necessary add ons, PSI readings, TDS readings, resin, membranes...you get the idea. Can someone point me in the right direction for information I can sift through? Any or all advice is greatly appreciated.

If I unit states it is 110GPD, does that mean it's "gallons per day"?

I have a 60 gallon that I was going to set up with tap water this weekend, but will put off a few more weeks until I get the RO/DI system all sorted out. It's been a major let down to say the least, but will be worth it to get it right.

Nøjo is offline   Reply With Quote
Old 11-19-2005, 01:07 PM   #2
Posts: n/a
Yes, GPD means gallons per day. The type of unit you need will have alot to do with the quality of your source water and indeed it's pressure through the "house". Higher TDS from the tap will mean a lower GPD rated RO membrane could be more advantageous as it will have a higher rejection rate and cleaner output before heading to the DI stage. Low TDS can allow you to get away with the higher (sometimes cheaper) GPD units.

See if this article helps with some of your questions...

  Reply With Quote
Old 11-19-2005, 06:16 PM   #3
Aquarium Advice Activist
Join Date: Oct 2005
Location: Victoria, BC
Posts: 113
Yes it does, thank you very much.
Nøjo is offline   Reply With Quote
Old 11-20-2005, 04:13 AM   #4
Aquarium Advice Freak
Join Date: Sep 2004
Location: Davis, CA
Posts: 429
TDS is your total disolved solids (in parts-per-million). After a trip through your RO+DI system, you should be at 0. Tap water is around 150-200 (or if you're me, 450-570 ). You have to use a TDS meter to get a reading. It may be a good investment to see that the system is operating.

Normal RO+DI systems have several stages:
1. a simple fibrous sediment filter
2. a carbon filter to remove chlorine
3. another carbon filter to remove more chlorine (chlorine destroys organic (the better kind) of RO membrane, so needs to be removed).
4. The RO membrane. This is the slowest part of the system. It takes in water and slowly pushes it through tiny holes to pass through only water. It also generates reject water (at a higher rate than clean water). Either pipe it to the drain, or some systems can feed it back into your hot-water line (more exotic, saves water).
5. The DI resin. Its a special ion-exchange resin that captures hard ions (calcium, magnesium, etc) in your water which may make it through the RO membrane. This is the part that generaly gets eaten up the fastest if you have hard water. While carbon filters can last 6-months to a year, the resin is usualy have that.

Higher input pressure leads to better filtered water at a higher rate.
55g reef, 2x250W 10k MH + 2x96W PC actninc, 10g sump, AquaC Urchin skimmer, 65lbs LR

xenia, mushrooms, wels. open brain, fungia radiata (orange), green eyed zoos

flame angel, mated pair of false perc, 6-line, firefish

20gH electric yellow cichlid
theatrus is offline   Reply With Quote
Old 11-20-2005, 06:02 AM   #5
Aquarium Advice Addict
Join Date: May 2005
Location: Central Kentucky
Posts: 6,015
Send a message via AIM to greenmaji
too high water preasure (around 80psi+) results in more rejection water/per filtered water and that is depenant on the flow rating of the membrane from the charts Ive seen..
greenmaji is offline   Reply With Quote

ro/di, stem, tan

Please support our sponsors and let them know you heard about them on AquariumAdvice.com

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
parameters i'm just not understanding. FastFly67 Freshwater & Brackish - General Discussion 7 02-18-2009 07:10 PM
need help understanding WaterIsWet89 Saltwater Reef Aquaria 10 01-06-2009 03:11 AM
Readings help understanding them Drewbie Freshwater & Brackish - Planted Tanks 7 11-03-2008 12:41 PM
An understanding of filtration Toker95 General Hardware/Equipment Discussion 9 04-04-2005 01:33 PM
Not understanding why... Hara Saltwater & Reef - Getting Started 3 08-31-2002 11:49 PM

» Photo Contest Winners

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -4. The time now is 05:10 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.