And that is exactly why I buy WYSIWYG corals. It’s pretty obvious if a corals plug is encrusted with coralline or not. No chance taken. It’s guaranteed. Good luck. If you happen to have a Reefing friend with coralline on their glass. Scrape it off with a razor blade and bottle it. That’s your best chance if you must have a product in a bottle. Lol!!!I am not looking to introduce anything new into the tank just to take a chance at them bringing in coralline algae.