Water Tanks in the Northwest take a beating. From constant rain for 6 months of the year to heavy UV exposure the other 6 months.  This can really put a strain on standard polyurethanes causing early chalking and excessive mildew, both of which can shorten typical life cycles.

Rick Gilbreath, Consultant for TNW knows this and has been pushing the extended life cycle benefits of Hydroflon, Series 701.  "Many times tank owners are required to wash mildew from tanks every 2-3 years so they can avoid early failure zones, especially on tanks without gutters". Mildew can act like "immersion" for coatings that are not designed to be under water.  This can cause softening and peeling in polyurethanes. Hydroflon, Series 701 delays the growth of mildew, but also carries a 97% cleaning efficiency when considering military standard MIL-PRF-85285D Section 4.6.13.

"On many local tanks, we are at year 25 in service with Hydroflon, and they still look like the day it was installed.  That could result in 30-40 year service prior to recoating.  What a difference compared to standard polyurethane and polysiloxane life cycles," says Gilbreath.