I'm not sure about that, but I will try and get you an answer ASAP!
More than 10 years
I'm just wondering why you'd want to use a ugf with live sand? The sand would get compacted in the filter plates and you're going to have a problem with all the accumulated debris that the UGF would pull through the sand which could give you a headache in the form of nitrAtes down the road... If you plan on using live rock (strongly urge you to) this would further complicate matters because of the lack of water flow through the filter plates under the rock.
Making it reverse flow (pushing up thru the sand using powerheads) may negate this but may make it difficult to keep some of the species that like to burrow in the sand.