another "ghetto" solution i did was to simply tie fishing line around the group of lettuce and anchor it around a rock sitting at the bottom of the pond.
all plants are gone now because they kept clogging up my intakes and filter floss... along with the plants i found out that there were fancy goldfish eggs and snail eggs on the plants so now i have fancy goldfish and snails in my pond but they wont last long... plus with the drip filter hanging above the pond finally completely seeded the water is crystal clear and at perfect params