You can siphon it off. Use the toothbrush attached to the end of your siphon hose and scrub as you siphon. If you can reach it, carefully remove it from the LR
with your finger tips. It's kinda slimy, especially after you get it out of the tank.
Speaking from current experience here.
29gal BB | 42+ lbs LR
| 143watts PC
| Asst. Leathers, Frogspawn, Hammer, XLG Open Brain, Zoanthids, Mushrooms, Diploastrea heliopora | Blue Mandarin | Atrosalarias Fuscus | Pair Captive Bred Ocellaris Clowns | Peppermint Shrimp | 6 Astrea's |