Water wetter causes buildup?

Will be putting my first water cooling setup together in the next few weeks an while reading the "infamous" tapeworm thread, a few people mentioned that water wetter may cause buildup like that. What's the scoop on this? Is purple ice any better? I don't want corrosion or algea but also don't want to be cleaning strings of buildup from my tubes. Any comments?

Ive used water wetter and Distilled water for several months and the water is still crystal clear .. as well as the Tygon tubing ...

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