Artyomka,
Welcome to the Nexus. I think tap water is fine for extraction purposes. But if you seek more pure and cannot find distilled, maybe just run your water through a filter first.
You know I must confess I did not even click on the link yours. Sorry to say it but there are so many half-arsed, incomplete "video" guides out there, it does not surprise me that folks have trouble getting results.
The Wiki link at the top of this page leads to our tried and true extraction TEK's. These TEK's have been used for years to decades to successfully produce freebase DMT crystals. Personally, I recommend Noman's Straight to Base:
Noman's DMT for the Masses TEK
Extraction is chemistry and requires time, sobriety and respect. Extraction is alchemical magic and shows you another world simply for working hard with plant matter. Given these facts, it is really worth taking time to not only extract correctly but to read and research.
Read over the instructions several times before attempting anything. Make sure questions are answered in advance.
When you do attempt the work take some notes on what you did and when. That way if anything goes wrong folks here can help trouble shoot.
I do hope you will have success in the future. Extracting medicine/drugs/sacrament at home is a great hobby.