Poeple have been having trouble with fiberglass tanks used with ethenol gas.
The ethenol dissolves the resin, releasing fiberglass strands enough to clog fuel filters. The ultralight and boating communities have mostly stopped using them. Some have had satisfactory results using a good tank sealer.
Now they're talking about bumping up ethenol in gas to 15%. Tank sealer might not work well with that mix.