question about RODI

[neemo]

I s it really necessary to process tap water through a DI cartridge?
I know the water will be more 'polished", but does anyone know if there are contaminants in the GTA's water supply that would require using a DI cartridge in addition to having it filtered through a regular RO unit?

Thanks
NMo

[Reef Mike]

You can use just standard RO (this is what I do) and it brings my TDS from 140 to 3. If on the other hand your TDS was initially high >300 I would think that it would be beneficial to use DI as will.

The DI cartridge would bring most water TDS to 0 along with removing a lot more of the silicates which can fuel a diatom bloom.

Its nice to have but not at all necessary. (IMO)

Mike

Oh ya.. Just get a TDS meter to see where you are in terms of input (city water) and post RO, and then make your decision if you are happy with what you are getting. If you are close to me you can drop by with a water sample and I can to a TDS reading for you.

BTW TDS = Total Dissolved Solids

[ajx22]

Originally posted by neemo
I s it really necessary to process tap water through a DI cartridge?
I know the water will be more 'polished", but does anyone know if there are contaminants in the GTA's water supply that would require using a DI cartridge in addition to having it filtered through a regular RO unit?

Thanks
NMo

Toronto water is run through a lot of old pipes. Problem with this is that there can be many mineral deposits (calcium, magnesium, iron and like charged minerals) in these pipes. RO will not fully remove these minerals - and this is where the DI section comes into play.

Detailled info on the process can be found in the following links:

http://www.aquariumpros.ca/rodi_info.html ~ How RO/DI works

http://www.aquariumpros.ca/TFC-Removal_Characteristics.pdf ~ What the RO membrane removes

http://www.aquariumpros.ca/tds_info.html ~ Info on TDS

http://www.aquariumpros.ca/chloramine_info.html ~ Removal of Chloramine - as Toronto uses this and NOT Chlorine


While DI in not necessary - it does remove the minerals and metals that can polute a tank over time. There have been many tank crashes that were unexplained for a long time. Recent studies have shown that RTN and other coral issues can be traced directly back to metal deposits in the water column building over time. DI would help assist in the removal of these potentially deadly levels in your water supply.

HTH,

[Reef Mike]

AJ

Just so we don't confuse things. An RO membrane on its own will remove >95% of all the things you mentioned and even 85-90% of silicates (this I just found out). The DI being a charge removal (removes anything with a charge) will finish the rest and remove all trace ions in the water.

It will mostly remove hydrogen and hydroxide molecules as those are the predominent charged particles in the water. In a more scientific term you will have pure H2O, as unpurified H2O exists with some ions (H2O<--->(H+) + (OH-))

Mike3

[neemo]

Thanks guys for your info.