Question About Deep Sand Beds

[grimreefer]

I am going to make a deep sand bed with Mangroves growing in it. My question is how to allow water to enter and exit the container. Will it work as efficient with the water coming in on the top side and exiting on the opposite top side, or will it work better if I make a couple of baffles that would make the water enter on the high side but have to filter down through the sand bed in order to exit on the low side. In short, will it work the same if the water travels across the top of the sand bed or have to filter through it? I can slow the water flow down to a trickle if need be.

 

[skriz]

The water will not filter through the sandbed. If done correctly, the dsb will have an anaerobic zone. My bottom layer was dry; and you know how much water I had pushing on the sandbed!

 

[grouper therapy]

A plenum(raised sand bed)would probably be more efficient in nitrate removal.

 

[grimreefer]

Thanks guys. I'm thinking about a container 24"x18" and have the sand bed between 8" and 10" deep. I am going to have the water maybe 1/2" to 1" above the sand and plant as many Mangroves in the sand as I have room for. Does this sound like it would do a good job?

 

[weaglereefer]

Last I heard mangroves weren't near as efficient at nitrate removal as chaeto or other macros. Seems like a better use would be a RDSB with no lighting, or a regular fuge.

 

[hackman72]

I wouldn't add the mangroves to the dsb itself. Once the DSB has it's established zones of aerobic and anaerobic bacteria, you don't want to disturb more than the upper 1". Slow flow is optimal and moving the water in from the top and out through the bottom would not serve the same purpose.

 

[cr500_af]

Is a RDSB a case where larger (as in container size) is better? When I put up the big tank I have a 29g that isn't doing anything.

 

[hackman72]

cr500_af;461927 wrote: Is a RDSB a case where larger (as in container size) is better? When I put up the big tank I have a 29g that isn't doing anything.

my understanding is no. Larger isn't always better. I forget the reasonings for it but I found it on wetwebmedia.

I'm mobile and get the link posted right now but go to http://www.wetwebmedia.com">www.wetwebmedia.com</a>

the filtration section under Marine has info on a DSB. I'll try and get you better info when I get a chance.