Is there a significant difference between brands of 3" chlorine tabs? It seems like prices vary greatly between brands and pound of containers. I'm interested in a tab that takes a long time to dissolve (slow release). I don't have a swimming pool, but rather a 12ft long by 6ft wide pond that's only 1ft deep. I presently keep the pond clean by rinsing out the cartridge filter regularly, brushing the bottom of the pond to agitate the dirt and then adding bleach and muriatic acid every few days. I know chlorine tablets would be more convenient but I wonder if it's worth the extra $. If anyone has used both methods (bleach vs chlorine tabs) and has any feedback, I'm interested in reading it. Again, this is not a swimming pool, but a very small backyard decorative pond.