The same thing happened to me when I got my pair of ocelleris clowns they were digging for about 2 to 3 weeks and it stopped. I wouldn't worrier about it to much. Another reason he might be digging is to "mark" his territory as mine did. My to little guys were digging like i said for about 2-3 weeks and they are always in That spot and don't seem to go into mt anemone

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10g softie and LPS tank(SPS soon

) coralife 28w 50/50 rio nano skimmer
Live stock
-1 Pulsing xinia
- Green candy cane
- green zoas
- GSP
- Fake percula clown
- Diadem dottyback

adding a 70w MH with 8 LED