Would not recommend ozone unless you really know what your doing. It can be quite dangerous at the doseage needed to be effective for your sized water volume. It's very effective as oxidiser (steriliser) and has a short half life so can't travel far under water but out of water is a different story as it's hard to detect. And becomes more dangerous if there are children or unsuspecting visitors unless you secure and signage.
UV is much easier but 2 x 55W may not be sufficient unless you only want to remove green water algae. Look towards amalgam UV tubes (high intensity) .
UV is much easier but 2 x 55W may not be sufficient unless you only want to remove green water algae. Look towards amalgam UV tubes (high intensity) .