ro/di hook up

[SCROLL][/SCROLL]This has probably been beat to death but I wanted some clarification. Should I hook my ro/di up before my water softener or after. I picked up a ro/di filter off a guy I work with and came with no directions and he didnt know the answer either. Thanks in advance.

 

After,as advised by AZdesertrat

 

I called Bulk Reef Supply when I installed mine. They also said after.

 

Agreed.

IIRC, water softeners work by adding/exchanging ions. For the most precise and stable representation of seawater, you need to start with purified water (zero TDS) from your RO/DI filter.

 

RODI goes after the softener.

The RO membrane can clean the salty water better than the hard water which is why you soften water first then run it through RODI. You will also get a lower TDS this way.

 

ALL RO membrane manufacturers recommend softened water, they will not consider any warranty claims if you do not do so.

 

How soft? My tap is ~145ppm TDS

 

Thanks for the reply. Tds reads 450 out of tap after water softener. So after the ro filter I should read 0 correct? Sorry but im very new to all this.

 

What is the calcium carbonate hardness of that 145 TDS water? It could be all calcium and magnesium which means the water is still moderately hard.

Yes, well sort of. The RO membrane does 90-98% of the TDS removal so it will usually be around 96% lower than the tap water TDS after RO only and 0 TDS after the final DI stage. Take 3 TDS readings, your tap or softened water, the RO only water before the DI filter and then final RO/DI TDS. You need to know the first two to calculate how well the RO membrane is performing, its called the rejection rate or removal efficiency. The final RO/DI TDS tells you the condition of the DI resin or cartridge.