I Dont know if anyone is looking to do or has been done but i just made my self a sandbag. Its a 4 ft sandbag and can weigh whatever you want. Mine right now is about 55 pds which i dont need but whatever lol i can lower it if need be but parts are a water bag for holding a pool liner and sand/gravel (I used gravel just incase i get a hole sand wont leak out). Thats it thats all you need. Total cost was $10.50
The 4 ft bag comes in 2 colors one black one blue. I used the black because its thicker. the black one was $6.00 and the 60pd bag of gravel was $4.50. I bought 2 black bags so i might make them 30pd bags.
This is it my pool store only had a 4 ft and 10 ft bag and nothing smaller. Some places sell smaller ones and square bags.