Backyard Aquaponics
A place to discuss aquaponics

No never drilled holes in them (too much work) just stirred them around with my hand.

Had it going about 1 year the only part that had a tendency to go anaerobic was at the bottom where all the crap collected if I didn't empty it regularly.

One of the problems with calculating surface area is that even if you work out the surface area of a bottlecap because of their shape they can partially fit inside each other.

Edit

BTW they have a SG of about .95 - .96 so they just float.

Thanks