I run a W in my sump with 2 catalyst and 12% H2O2. This is in a 220ish total water volume. In hindsight I should have purchased 2 smaller units, it would have been easier to get in and out of my sump. Depending on your sump set up, this may not be an issue.
Good luck with the new build.
Dave
Good luck with the new build.
Dave
