I think the right algorithm for something you put a lot of effort in (like I did for Shadergif):
1. Post on HN.
2. If upvotes <= 3:
Post the next day.
Maybe you did not get the attention you deserved. Try tweaking the landing page a bit. Maybe you can change the title, add more screenshots of your UI on the landing page.
3. Iterate on your product or work on a new one, but don't post a similar thing again for 6 months.