nobody has really come up with a method to really make sand work correctly. the undergravel filter idea is not that horrible, the problem is that it is really hard to pull all of the detritus through the sand bed then back up through the tubes to be collected somewhere else to be removed. the plenum system comes pretty close, but it is a bit difficult to do right and it really takes up a lot of space in the tank. leaving very little room for the stuff we really want to see and keep.
as long as regularly clean your sand bed very well you can keep phosphates under control. it is just very difficult to do this without disturbing the LR. some people use PVC pipes cut into sections to rest their LR on and some have acrylic stands. they all accomplish the same thing raise the LR up off the sand to keep the phosphates from wicking up into the LR and to allow you to more easily clean the entire bed of bacterial flock.
we can get into more sand bed husbandry if we want, just let me know. i am going to focus on phosphates for now.
i chose the epoxy bottom
on my system. i will also do this again when i start on my new system. this allowed me to have as much flow as i wanted. the detritus did not have a chance to accumulate anywhere in my display. in fact i would only have to siphon out a few places of sand every few months. the sand was formed by the bacterial turgor breaking off little bits of the LR structure. i did not have any sand in the tank at all. all of the flow allowed the detritus to either be removed by the skimmer or accumulate in my sump, which i vacuumed out every week when i did water changes.
ok, next food for thought. what make you pick out a piece of LR?