Tapwater TDS is Around 10 Can I use just DI or just RO?

[liam2317]

I am slowly gathering equipment for my first reef tank and oh man the cost of these things adds up fast!

 

I live in Vancouver Canada and we have some of the cleanest tap water in the world, our TDS from the tap is usually 10 or less. Some people have said they have seen it go up to 15 after heavy rains but I have not seen more than 10.

 

Can I skip the RO-DI unit? Probably not. Can I just use an RO unit or just a DI unit? I will test the TDS of the tap water before processing and if we are having a high TDS period I can always buy water for a while.

 

If I can use just one or the other which would you recommend?

 

Thanks!!

[SushiYum]

I would still buy a rodi unit. It just means u can use the filter for a long time before needing replacement.

 

But u can always try...see if u crazy algae growth still

[AZDesertRat]

I would use DI only if your tap is only 10. I say DI only but I would still add a 0.5 or 0.6 micron carbon block in front of the DI to act as both a particulate filter and to remove the chlorine so the DI lasts longer. You should be able to get 300-400 gallons out of a single full size 20 oz vertical DI cartridge and you will not have the waste of a RO.

[kush.]

listen to that guy^ lol

[liam2317]

Great, thanks for the advice! I'll give the DI + carbon block a try.

[seabass]

In the long run, a RO/DI unit will save you money. Even at 10 TDS, you'll be burning through DI resin. You will have paid for the unit by the fourth replacement DI cartridge (after that it's all savings). AZ will be the first to tell you that a higher rejection rate (lower TDS entering the DI stage) means saving lots of money on DI resin. The great thing about such clean water is that by using a RO membrane first, TDS entering the DI stage will be around 0.2 and your DI resin will last a very long time. It's almost like running a dual DI system.