RO or RO/DI?

[civitan.erichanson]

I am planning my 55g reef tank and developing my budget. I notice that there is a bit of a price difference between a straight RO unit and an RO/DI unit - what are the advantages of having the DI?

 

Thanks,

 

Eric.

[magnetic1]

I am planning my 55g reef tank and developing my budget. I notice that there is a bit of a price difference between a straight RO unit and an RO/DI unit - what are the advantages of having the DI?

 

Thanks,

 

Eric.

 

Filters out everything the RO didnt

[jnguyen4007]

Filters out everything the RO didnt

 

 

It filters out so much that if you taste RODI water, it will make you want to gag. What gives RO water that great taste to us is many of the elements in the water that the DI take out.

[ArtC]

'Everything the RO missed is an exageration', but say the RO takes out 90% (of whatever your water has to begin with, varies greatly) then the DI takes out 90% of what is left. Just using DI resin to take out everything is too expensive, which is why the units all put RO first. Also, RO works better at high water pressure and low pH, so YMMV on that part of the system.

 

Hard to say what the DI is taking out, but whatever it is, you don't need it in your tank. I had a cheap RO when I started, and I had algae everyplace. Finally got sick of spending my weekends scrubbing rocks and bought RO/DI. Haven't seen a strand of hair algae since.

 

Whenever you want to know more about tank chemistry than you really need, check out Randy Holmes-Farley articles and forum on reefcentral.com. Here's one for RO/DI:

 

http://reefkeeping.com/issues/2005-05/rhf/index.php