Leadmasters makes a 1 pound weight that is moulded to fit the outer hoop and it has a couple of holes at each end for the zip-ties to attach it.
I usually add two pounds when I'm hooping deep in S.M. Bay but you may want to add 3 or 4 pounds if the water is really flowing in the bay during a big tide change.
Some guys go to Lowes or Home Depot and buy some lengths of galvanized chain that fits the circumference of the hoop and then zip tie that to the inside of the outer hoop.
If it's shallow enough and the conditions allow, I give the net a quick lift and drop after it's hit the bottom, to make sure it's sitting flat down there.
Good Luck Hoopin'