RO or RO+DI

[dberrong]

I'm looking into purchasing an RO unit, but I'm a bit confused as I often am when trying something new with my tank. Should I simply get an RO unit or do I need the RO/DI unit? What exactly is the difference?

Thanks.

[Grue]

Ditto, But I have a ro unit do I really need a DI?
And as I have come to learn Ask MELEV!!!:D I did find this on his site http://www.melevsreef.com/ro_di.html
Grue

[dberrong]

I had read that article from Melev. It still doesn't explain the difference between straight RO and the RO/DI. I'm sure that we should get the +DI, but I'm a cheapo and try to save money on everything I do.

[Reptoreef]

Well... look at it like this: lets say your water source has a TDS of 100-150 or so. You add an RO only and that drops the TDS to around 2 to 7.5(95 to 98% pure water)... that's a great range IMO. Now, lets say your water source has a TDS of 300 and you add the RO only and that drop your TDS down to around 6 to 15(still safe IMO, but border line). Above any levels 300, I strongly suggest the use of a DI resin following the RO process. I have a municipal water source of 250-300 and use RO and DI to filter my water.

[greg97527]

www.airwaterice.com

good but inexpesive ro/di units

[dberrong]

Well... look at it like this: lets say your water source has a TDS of 100-150 or so. You add an RO only and that drops the TDS to around 2 to 7.5(95 to 98% pure water)... that's a great range IMO. Now, lets say your water source has a TDS of 300 and you add the RO only and that drop your TDS down to around 6 to 15(still safe IMO, but border line). Above any levels 300, I strongly suggest the use of a DI resin following the RO process. I have a municipal water source of 250-300 and use RO and DI to filter my water.

What do I use to test my waters TDS?

[greg97527]

a tds meter, i happen to have one left for 20 shipped. you can get them on ebay or airwaterice etc as well.

[dberrong]

Does the one you have test anything other than tds? What is the brand?

[melev]

RO/DI water is the purest water you can put in your tank. RO water is good, and many people purchase that water from the LFS and lug it home in jugs, but RO/DI is even more pure. The best water we can put in our tanks reduces the nuisance algaes some people suffer / endure.

The system I offer is cheaper than the same one sold by Air Water & Ice. I just had to point that out.

A TDS meter only tests TDS (Total Dissolved Solids). A handheld meter is much more useful compared to one that is "in-line." I've used Hanna in the past, as well as HM Digital.

[spookey]

good info ty melev