$160- 220+.... and I read that the diffuser is "a consumable item and will need replaced periodically. If you are using this product in accordance with the instruction manual, can be used for 9 months to 14 months"
I have no idea how much the diffuser costs.
They also have a Twinstar Shrimp that is supposedly just for shrimp and disease control. I *think* it is supposed to learn and adjust to your shrimp environment.
Never used it, but if I had one or a large tank it may be worth it.
As it is, I have too many tanks for it to be worth it.