[underseaworld]

I am looking into buying a ro unit. What are the best out there? and where to purchase.
Thanks ed

[Reefland]

I think most of the available units are built relatively well and have good performance. They all accept the same cartridges and that is where your performance lies. I like a good 4 stage unit that produces at least 70 gallons per day and personally use an AquaFX model which is a sponsor of our site. This does not mean they are the cheapest but they provide great service if/when needed.

[WHOSYOURDADDY]

I agree with Reefland the technology is the same so it really comes down to how much you want to spend.

For my 55 gallon I went with a 5 stage Mako RO/DI system that was large enough to make double the size aquarium I had, the 100 gpd unit is what I settled for (along with the 40 gallon storage tank with replacement filters) the size of your aquarium (135gal) would suggest at least a 100 gal per day system.

[Samper]

I was very impressed with the service and quality I got from buckeyefieldsupply.com
He spent hours with me explaining every little thing that I wanted to know and didn't seem to mind my endless and sometimes idiotic questions. Customer service is key in my book.

[underseaworld]

What is the purpose of DI on the Ro unit?
I need to buy large enough to handle a 300gl tank.
So keep the suggestions coming. Thanks again

[AquaFx]

Underseaworld,

The water that evaporates is free from Dissolved Solids (Total Dissolved Solids) Salt being an excellent example of a dissolved solid.

Example: If the original TDS of the water is 100 after evaporating off pure water and adding water with a dissolved solids concentration of it's own. you will create a "thicker and thicker" water.

In other words, you want to add back only what has been removed. Also things like fluoride are removed (which is a dissolved solid also)

Marianne
www.AquaFX.net

[dougc]

The RO membrane should remove most of the solids from the water. The DI cartridge is there to remove anything that gets past the RO membrane. The DI cartridge is the last step because it is expensive and has a limited capacity to absorb contaminants. In the long run, you can save money by purchasing a TDS meter and not getting the color-changing DI cartridges. The TDS meter is the best way to determine when the DI cartridge needs replacement and to check the health of the RO membrane. The carbon cartridge should be replaced every few months because it removes things that can damage the RO membrane.

[Steven Pro]

If you want the best, buy a SpectraPure.

[#99]

I agree with STEVEN PRO,that is all I used,and being from phoenix like I am,they are in Tempe and you will get excellent cust. service.The water is so bad here(Phoenix area),about 600 on the TDS meter out of the tap.In order to get it down to close to zero,you might need 2 DI cartridges.Also I used the non-color changing DI resin because it leetches dyes into the the tank.So I used a TDS meter to tell me when it was time to change the cartridges.I ran a store,so when it got to be 20% of the total TDS I changed all but the membrane which I changed every 3 months.Also the more gpd the membrane puts out the more often you will have to change it.
Matt