sandsifting stars

[wildthings44]

I have heard that if the bed isn't stirred that dangerous gasses build up (on of the main reasons for trying a horseshoe) and I can see these bubbles in the sand (well they are bubbles of something anyway) I have wondered if this is really all that bad as this seems to be where the creepies are.
Also, looking to set up a 20 gal as a refugium under my 60. I plan to take out half the sand in there and add mud. Do you think it best to just go with mud or keep some of the sand?
Thanks
kim

[cyberchef]

Originally posted by Sylock
Jen,
My thought process comes from a few places.

Obviously I'm relying on Ron's information being the most 'expert-wise' in the DSB realm.

[MontanaRocknReefer]

I have a Tiger Tail cuke in my reef tank for over a year and it divided one time. Here is a pic of the little one: