Is de-ionised water better than nothing?

I am very new at making Colloidal Silver - I've made about 8 batches of 8oz Colloidal Silver , using a home made generator with four 9v batteries. I'm fascinated by it all and also not too sure if I'm doing it right.

My biggest problem is getting hold of distilled water. I live in England and you wouldn't believe how rare this stuff is now. I'm sure I can remember a time when we could buy distilled water easily. Now it's like gold-dust, LOL. So I'm thinking of buying a distiller. Only problem is finance. I am always totally skint - hence the four 9v batteries.

Could I make Colloidal Silver using de-ionised water, which can be bought at any garage? For the moment the choice for me is colloidal silver using de-ionised, or not make it at all. In other words, is de-ionised better than nothing? Or would it be detrimental?

Thanks in advance for any info or advice.