dsb and filter?

[Jonnyacrofeed]

Hi I was reading in a saltwater handbook the other day and it said that if you have a dsb you should have an undergravel filter installed. It said that if you dont have one you should not go deeper than 1/2 an inch with your substrate or you could get anaerobic conditions producing toxic gases like methane and hydrogen sulfide. Is this true, do most people with a dsb have an undergravel filter installed? Thanks.

[Saltz Creep]

No, an undergravel filter defeats the purpose of a DSB. A DSB does produce anaerobic conditions which is desired for nitrate conversion to nitrogen gas. Methane and hydrogen sulfide are also produced but they stay confined in the deepest layers. This is why the sandbed should not be disturbed.

[Jonnyacrofeed]

I have about a 1 inch to 1 and 1/2 inch deep bed of reef sand from caribsea. Could these harmful conditions happen in my substrate?

[Saltz Creep]

At that shallow depth the sand should remain aerobic.

[B Pierce]

IMO undergravel filters are crap. You don't need them to have a DSB.

[Jonnyacrofeed]

So does a ssb like mine offer any advantages?

[romunov]

See here for a list of DSB articles (http://gutfeeling.mine.nu/my/dsb.html). I've linked to the latest Toonen article where he compares 24 experimental tanks with different sands and depths. Interesting. :D