It works on Chrome for me, but on Firefox it just shows the background color

Thanks for checking. Apparently firefox does not let you use an internal svg image as a filter - https://bugzilla.mozilla.org/show_bug.cgi?id=1538554. Trying to see how to work around this.

Using an external url fixed the issue.

Awesome, thanks for fixing it!

If you want the repetition to be even less distinct, you can use multiple layers with different tile sizes (which ideally aren't multiples of each other).

Thanks! Will give it a try