C27 Holding Tank

[John]

The prior owner of my C27 replaced the original holding tank with a stainless steel holding tank fabricated by a local shop. It is difficult to determine when it is time to pump out. Is stainless steel appropriate for this application? Should I replace? If so, with what? What is the most reasonable method of monitoring tank level? Lastly, should my tank vent line have a "dip" or trap in it where waste can collect? It seems to me that the vent line should have a continous fall from the vent fitting at the stern down to the tank.

 

[Peggie Hall/HeadMistress]

Metal is not a good choice for waste holding

Urine is so corrosive that it typically eats through a weld in a seam or fitting within 2-5 years, and will turn even a stainless tank into a collander within about 10 years. But--That's what you have...and it's not leaking now, so I see no reason to replace it till it does. When it starts to leak, replace it with a good quality thick-walled plastic tank. Meanwhile, add a gauge (the Snake River AcuGage would be my choice...you'll need the internal sensor for a metal tank) so you'll know how much is in the tank and when to pump out. When you do have to replace the tank, just move the sender to the new one.The tank vent line should NOT have any traps in it (nor should the tank ever overflow into it, either!)...it should be as short (5' or shorter) and as straight as an arrow.