Thank you Lesley but here is my answer to the surface area of the Bio Ball vs your suggestions.
These are simple plastic pieces that are designed to maximize surface area, here are some examples of the surface area that they can contain.
For every cubic foot (12 X 12 X 12) of your average bio-balls there are 100 square feet of surface area. Some bio-balls now contain 200 square feet of surface area. And there are many in between this range. For instance. The 1.5” pronged ball, has 13.05 Square Feet of surface area per Gallon or 75 Bio balls per gallon or 160 sq. ft of surface area per cubic foot.
1" bio-ball. One gallon=approximately 225 bio-balls=surface area of approximately 21.5 sq. ft.
One gallon of Coralife Bio-Balls, (approximately 250 balls) has a surface area of approximately 21.5 sq. ft. This increased surface area supports between 45 and 60 gallons of marine life.
1000 of these bio balls can contain a surface area of aprox. 95.56 sq. ft.
There are other types to be sure like bio wheels, or elongated bio balls, some that look like an hour glass all with equal or sometimes better results.
There sure are tons of things that you can use instead of bio balls. Plastic golf balls, chopped up UGF, weed wacker string, toy army men, tons of plastic what ever you like. But they are not designed like the bio ball for MAXIMUM suface area.
Thomas