Deep sand bed setup

[NubNub]

Hello

I am setting up a deep sand bed in my refugium, from what I have read I should have 1-2cm gap at the bottom with no sand. What I am stuck on is what to use to hold the sand above the gap?
Should I be using perspex held of the bottom with holes drilled in it and let some sand through but I feel this would slowly fill the gap at the bottom. Apart from that I'm not sure how to have a gap at the bottom.

Anyway any views would be welcome and examples of how people have set there deep sand beds up would be much appreciated.

Paul

 

[brandon429]

If you wanted to research some of the newest stuff people do with deep sand beds, research/search out using sponges at the bottom of the tank w sand on top. Its a big thing they're doing in Japan for reefing and some threads exist on it. its for creating the right aerobic zones to accomplish nitrate reduction...

what you are contemplating above is called a plenum setup and its been so long since Ive seen one I forgot what they use to separate the layers

its fun to experiment with sandbeds and what they can do. people run tanks without them, with them, or with sand that is totally cleaned occasionally or just partially cleaned occasionally, so many different ways to the same ends/coral growth

 

[NubNub]

Hello

Thanks I have a name to search for now. From what i have read it is meant to be one of the most important parts of a deep sand bed, but I could not find any examples of it. From what I see most people fill right to the bottom. Not sure if this means it make no difference of just fell out of fashion. I will carry on with the search with your new clue and hopefully find out what is use and how it's done.

Paul

 

[Eagle_Steve]

we used to use 1/2" pvc pipe as the base. Match it to the tank bottom use tees to make cross braces if it is a big tank drill holes throughout the pipe for air to escape. Place eggcrate light diffuser on top of that, fastened with zipties. We would then use the black colored "blackout" screen for screen doors or window screens. The holes in it are very small and the majority of sand will not fall through it.

Search this"Jaubert Plenum" and there should be a ton or articles on it. I believe Julian Sprung did an in depth one years ago for Advanced Aquarist.

 

[fish farmer]

I think the grain size for a plenum was 2mm. I believe they weren't that "deep" either like under 4 inches. A LFS I frequented in the early 2000's had a plenum in his display which he preferred over the deep oolitic sand bed talk of the time. It was probably the only thing we argued about at the time.

 

[NubNub]

What were your cons about it over a oolitic one.

 

[fish farmer]

I was caught up in the fine grained DSB trend at the time with my beginning reefing experiences and feeling that a natural ecosystem with all the bugs and critters and zero maintenance sounded the way to go. I never tried a plenum so I have no real experience with it long term, but it looked successful on paper.