Re: Suthdown - tropical sand - ammonia/nitrites

"RicSeyler" <ricseyler@xxxxxxxxxxxx> wrote in message news:isvDf.16891$3m4.9553@xxxxxxxxxxxxxxxxxxxxxxxxx
But you DO want that oxygen-free area at the bottom of the DSB. 

I have done some more reading about freshwater heating cables
and now I know what you were talking about: freshwater folks want
to encourage convection water currents using heaters. Warmer
water circulates to the upper layers of the substrate inviting colder
water to the bottom layers... This way they avoid oxygen-free areas.

Thanks for mentioning this, Ric! Now I need to do more thinking ;-)
.