We use chlorine feed pumps at the three 500,000 L. commercial pools we take care of and have had no problems to speak of at all in the few years we've been using them. I have a call in to Pool Pilot Canada about whether they have experience with SWC's in otter pools. If they tell me it's a good idea, that's the route I'll be taking.
We are going to be custom building some type of cage to cover the entire floor and any skimmer openings. Sadly, a few months ago they lost an otter to suction entrapment, so we will be taking many precautions to prevent this from happening ever again.
We are also thinking that since otters fur is so oily that Natural Chemistry's Pool Perfect would be great to reduce the oils.

I'll definitly post some pics when I'm finished.

Brad