sand bed maint.

in case you need more info on the tank. http://www.3reef.com/forums/say-hello/swiming-not-drowning-73599.html
i need some input and sugestions. just worried about a CRASH, it has been in this tank for about 5 yrs and i dont think anything has been done other than some siphoning SOME of the crap off the top, (and yes in it also, i didnt know what i was doing and why, see post listed above)

1--- how do you maintain a sand bed (3-4 inches)

options--- make it deeper, make it shallower, get rid of it all, leave it the same? what are the risks and benifits of all (in your opinion)

2--- if making it deeper, how would you go about it?
if makeing it shallower, how?
if getting rid of it all, how?
if leaving it the same, what is the maint?

 

Seeing as the tank is new to you and the sand bed very old I would either replace it or not touch it. Get a sand sifting star fish and let it do the dirty work for you. If you stir it yourself it may cause more problems than it fixes.