DIY rock Purple coloring?

[Tnconcept]

Hi guys I'm trying to see if any one got a recipes:wave::bounce3: for putting purple coloring in your DIY rocks?? Thanks.

[Tnconcept]

So there is no one that have tried to put any substance for getting the purple color in these DIY rocks??

[huig]

There is really no need to color rocks, all that is needed is a little patience and coralline algae will grow and fast for that matter. after about 3 months you' ll notice they start to appear.
After a while coraline algae growth will even be a PITA as it grows on the glass and you need a blade to get it off, eg. from my pump screens it' s only possible to remove it with vinegar.