I like to use the IO 200 gal box. Only thing I hate with this is the bags are flimsy and often the seal is not good. When this happen, there are spill. But more important, moisture get into the salk and the salt cake up. When this happen, the salt will not completely dissolve. I really hate this. I am sure it is the CaCO3 that cystalize and then not redissolves.
I wish they use better bags for the 200 g boxes