Hi allanflowers
Your prayers have been answered. I too suffered with the Sullivan type tanks you refer to. One day at my hobby store they had no more Sullivan tanks so I tried another type. It is the Hayes tank. As soon as I installed it I saw it as a superior tank to anything I have ever seen in our hobby (28 years flying R/C). After a few flights I purchased enough new Hayes tanks for my small fleet and discarded the Sullivan tanks before they gave me any problems. The best part of the Hayes tank is that it uses a very small O-ring seal. By being small the seal and the hole it engages with is extremely strong. Some of my Hayes tanks are over 6 years old and seem to last forever. I don't have to bend any tubing.