Do I need a DI unit?

[Russ]

Hi,
My RO unit has product water around 12ppm TDS, from what I read most RO units have around 2 or 3ppm. Do I need a DI unit for my system, my goal is to breed.

[Carol_Roberts]

What is GH of your tap water? You want tds between 50 - 100 for breeding, GH 3 - 6.

[Russ]

The GH is 6 the last time I checked.

Russ

[raglanroad]

Russ, I see no reason possible, that anyone should need DI for freshwater fish. RO water is plenty better than tap, and low enough in TDS to be made into any GH you want.
As for DI, one test of DI water showed 120,000 bacterial count per ml. The resins appear to foster the growth of bacteria. This is one person's experience, lab tested.
For marine, the salt will kill the germs.

[Russ]

Thanks, that saves me some $$.