Imo tank aint a tank without sand. No sand makes easier cleaning though so thats a pro . About it holding more parasites they will mostlikely hide in rock before sand . It may help little but dont think to much. If u not gonna qt fish u taking a risk u will have to deal with if u get something . U can treat like my 90 but its even not fool proof things like flukes abd black ich yes black ich dont get killed by most stuff like copper. U need prazi to treat that kinda stuff and who keeps there tank dosed with prazi that chit aint cheap. I know u been buying angels left and right abd they r nortorius for flukes u could always fresh water dip and watch ti see if any fall off usually takes only few minutea if they have some to c one fall off. So any way since u going to be at school soon idk if u want to mess with tank what happens if something goes down when u gone . U parents know how to handle illnesses ?
Flukes, black ich, anything with worms, I can deal with easily now so that isn't a big problem anymore. I am doing round 1 of 3 with prazi right now.
Another big problem with the sand is that it stirs up so easily and becomes all piled up on either side of the tank making the center with about 1" sand bed and either side about 3-4". Any fish that decides to eat a pellet off the sand bed causes a little sand storm and the sand ends up falling all over the rocks. Gets kind of annoying after awhile....
What about swapping the sand or at least half of it with something a little heavier? Don't want crushed Coral though.
As for the parents and me going to school, I am trying to take care of as many things as I can now before starting so the tank requires as little maintenance as possible.
A shallow sand bed provides almost no purpose except aesthetics. It becomes a detritus sink if its not cleaned thoroughly with nassarius snails and others, but it is just for looks unless its 6+ inches deep, and DSBs have their own longevity dangers such as sulfur hydroxide releases and more. BB is easier to clean but all that poop just absorbs into the sand otherwise, hence the need for CUC, otherwise it would build up a LOT and then stir it once and there's an ammonia and nitrate explosion.
It really just becomes a preference in looks. And livestock choices, as some fish/inverts require sand.
So anything under 6" is useless to help with the nitrate? My fuge is currently 6"+ of sand but that is in a 29 gallon tank supporting a 125 with a 2-3" sand bed.