Aluminum Holding Tanks

[Peter Milne]

Peggy,Our 96 Hunter still has its aluminum holding tanks. While I recognize they will have to be replaced, I have been putting off the inevitable (so that I can get on with more pleasant tasks)with the following routines:1. Instructing all aboard to flush with lots of water;2. Emptying the tanks daily (except when in harbour);3. When we will be away from the boat, both tanks are thoroughly flushed with fresh water, then 1/2 filled with water (fresh)and treated with a generous dose of ODORLOSS; and4. Close inspection of the tanks on a regular basis.Plus, because the water up here in the Pacific NW is so cold, I rationize that any chenical reaction with be much slower.Am I kidding myself or can I reasonably expect to get a few more years out of my tanks?Many thanks for your counsel on this and so many other sensitive issues.Peter MilneS/V Blue Heron

 

[Peggie Hall/HeadMistress]

You're living on borrowed time

But you are extending it a bit. Although cold does retard biological processes, I'm not sure that it has any effect on corrosion. Thoroughly rinsing out the tank every weekend (which is a major PITA) so that no urine can sit in it is doing the most to slow it down. The only thing that Odorlos accomplishes is odor prevention...neither it, nor any other holding tank product, neutralizes urine. The best thing you're doing is regular inspections, especially the welds at seams and fittings...'cuz that's where the first leaks are most likely to happen. You might want to add an annual pressure test to your inspections. Easiest way to do that: Fill the tank with clean water...block the vent, pump the toilet till you feel significant resistance from backpressure, then go away overnight. Next day, unblock the vent and check the tank and surrounding area for any dampness. The time to replace the tank is when you find any...till then, it ain't broke yet, so it doesn't need fixing.

 

[Jim Rushing]

Leaks

It always leaks under the tank at a weld. The weld will look good, but will develope a pin hole. The leak will be so slow that it will take weeks before it reaches an area where it will be noticed. Also, if you have a wet bilge, you will never know until the bottom drops out. I have a dry bilge and keep it that way because if there is water, I want to where it is coming from. It took me two weeks to realise that I had a problem somewhere. And there was no smell until I removed the aft cabin panel and reached the tank. I had planed on replacing the tank someday, but someday is this week.

 

[Brian Leney]

1995 holding tank failed

Peter,The aluminum tank on my 1995 H37.5 failed last summer, sailing area the Chesapeake Bay. I too did plenty of preventive maintenance knowing of inevitable failure. I routinely pumped out after each weekend of use and followed it with a fresh water flush.My advice is to shop for replacement tanks now, assuming you will have the boat a while, since you will need the tanks eventually.