How many days for wash to produce alcohol with turbo yeast?

[Flyakite]

Made a wash last friday with Triple distilled turbo yeast (I know its frowned upon here but came with still) sugar and liquid carbon.
Its been bubbling away at around 20 degrees since then.
Yesterday cusriosity was getting the better of me so I got the hydrometer out to check alcohol levels but its saying zero.
I thought by this stage (4 days ) it would be showing some alcohol content.
Is this normal?
I have had a good readd of the forum but cant see answer to that particular question.
Thanks,,