If you run the water through the UV at a high flow rate you will kill off less of the beneficial but you have to remember you cant always assure the water is 100 percent clean.
Better safe then sorry.
The farther you go out into the ocean the more diluted the water is because its farther away from the shore.
Better safe then sorry.
The farther you go out into the ocean the more diluted the water is because its farther away from the shore.