sump review

[afreshoutlook]

Greetings,
I am into my 8th week of a new set-up in a 72gal. bowfront. Currently I have approx. 70-75 lbs.L/R some previoulsly cured, 3 peppermint shrimp, 1 brittle sea star, 1 red sea star, various crabs & snails, 2 percula clowns added in week 5, 1 moorish idol in week 6 and a potters angel week 7. Also colt coral, Kenya tree coral, mushroom rock, various frags zenias etc., all seem to be thriving.
Now for the sump, it's a 20 gal. with bio balls, also a sea clone hang-on in the sump with a Rio 2500 pump, which will be upgraded very soon, a few crabs which came along with the box of L/R in the pump side. All seems to be working well here also,

My question is: I have heard that I should not be using the bio balls any longer. If this is the case, what do I peplace the bio balls with?
As you can see from my descripition of hat is in the tank, I can only see adding a few more fish & possibly a few more soft corals to finish off the tank.
What's next????

Thanks for any assistance
Dwight