Sand beds: What do you need and why.

[midgetwaiter]

There's no questioning that a deep sand bed or plenum does a really good job at removing nitrates, the science behind it is pretty well understood. Where people run into problem is actually getting the thing to work right, too many people end up with it turning into a nutrient slough.

I'm not sure there is an easy answer answer to getting it working either. You have to have the right amount of critters working to keep it clean but you can have too much of them as well. Sometimes putting something like a cucumber or sand star in there just results in having all the bacteria you are trying to keep going eaten and you end up with a crash eventually. It's a delicate balancing act.