We also get concrete block seconds meaning blocks that are defective and can't be used for anything else. I get a pallet of blocks at a time in my old pickup. I will form a reef by throwing 4-6 pallets of blocks into the lake. The reef starts at the bank and goes out in the lake as far as I can throw the blocks. Occassionally I will carry blocks out with a boat to extend the reef.
There are many advantages to these concrete reefs. Of course, they attract a lot of bait fish. It is easy to fish along the sides of the reef. Also, we tend to not get snagged on these blocks. And, certainly, they last forever.