Quote Originally Posted by Photo Engineer View Post
As I said, use distilled!!!!! It is less expensive and is perfectly fine.

Using DI water instead of DW is like using a cannon to shoot gnats.

The only thing worse (more expensive and uselessly so) would be to use DI DW. That is way overkill.

Use Distilled Water. Here it is less than $1 / gallon. You can even buy small stills to make it yourself.

PE
There are various grades of both distilled and deionized water. Simple, single distilled water is made in large quantities in many urban areas and is, indeed, cheap. Triple distilled water using tin condensers is used in some chemical and electronic processes and is very expensive. An elaborate deionization and filtration setup can produce water of about the same quality as triple distilled at a somewhat lower cost. A simple deionizing scheme can produce decently pure water at a cost only slightly higher than distillation and at a significantly lower hardware and setup cost. For very small scale water purification, deionization is usually the way to go.