If there were, the
medical community would be all over it. But it's NOT uric acid that "eats" metal, it's the sodium chloride. 10 years is the average lifespan of any metal waste tank and it doesn't matter how often you
pump out and rinse out the tank. The first
leaks usually occur at weld--a seam or a fitting while urine is gradually turning the bottom of the tank into a colander. When it became necessary to use holding tanks in the mid-late '80s,
aluminum was the industry's choice because it was
cheap. But by the mid '90s, seamless rotomolded polyethylene had become the recommended material. There are a number of mfrs and quality varies. The best quality tanks have thicker walls to support the 8.333 lbs/gallon that sewage and
water weigh without flexing or bulging. Plastic tanks last as long as the
boat lasts so you'll only have to do it once.
So do yourself a favor and replace the tank with a plastic tank before it starts to leak. Ronco Plastics
Ronco Plastics marine Tanks is your best source. They make TOP quality thick-walled water and waste tanks for a very reasonable
price and have more than 400 shapes and sizes, over 100 of which are non-rectangular, and they install fittings in the sizes and locations specified by the customer when they make the tank. There are retailers who sell Ronco tanks, but Ronco sells direct for a much lower
price...and they're great to
work with.
When looking at drawings it's important to know that there is no top or bottom until the fittings go in, and YOU decide where they go. So rotate, flip in any orientation to find the tank that fits your space.
--Peggie