perhaps a stupid question.....surely a stupid question....

we all know disturbing the sand bed is taboo because it may release trapped toxins in it, but then why do we get sand shifter fish, snails and or shrimp?


......and starfish


http://cdn.memegenerator.net/instances/300x300/38526213.jpg

 

Quite a valid question actually.

Sand sifters stir the sand, keeping it clean and aerated, thereby helping prevent the build-up of toxic gases.

 

but arent the anaerobic bacteria present in the sand bed suppose to take care of said buildup?

interesting signature article btw Mr.B

 

Nitrogen gas is the end result of anaerobic bacterias conversion of Nitrates.Most sb's are not deep enough to allow this bacteria to grow.Using ss fish/inverts clean small areas at a time so there is not as much danger of them oxygenating the bed and killing that bacteria. I never disturb my sb but there are many who vacuum it regularly.Either way seems to work however If cleaning the sand is not your regular maintenance or you have a dsb doing so may cause a cycle.

 

merci les gars, good to know. no way in may am i ever going to vacuum my sb major pita, its about 5-7 cm deep

 

And this is why i have no substrate in my reef tank.

 

One also needs to consider that sandsifting critters generally stir small amounts of the substrate at a time, and if they tend to only work in their "home" area, the repeated action in that spot will end up keeping it pretty clean in terms of toxic buildup.

Additionally, many "sifters", esp. sifter stars don't actually stir the upper substrate, but gently turn it over, which tends to keep contaminants out of the water column.