If you could put some legs so as to raise it up maybe 2-3 feet you will get more longevity out of the reef as it will settle at least a foot more than likely. I have built structures like that and you want as much vertical relief as you can get. The floats {Fad-fish attracting device} you are talking about putting on top of it will really make it more productive. Try a bunch of floats and hang about a 6 foot long piece of scrap shrimp net on the fad. That attracts the bait fish real well.
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