Mike ,I will zip tie the usj to the eggcrate then cover it up as much as possible with substrate.Dont worry about getting any gravel/sand in the jets as soon as you turn it on they will clear them selvs.The way I made my jets is cut 2 3/4" pieces put one end in boiling water for a few minuets and used a pair of channe locks to squeeze the end together.It dosent have to look perfect just work and they will not really be seen if placed stratiegicly.