Summary for stainless steel sewage tank Discussion
stainless steel sewage tank owners should not use sulfuric acid to try to dissolve toilet paper or flushable wipes. Ken Yada, asking about a 400-gallon vented stainless tank on a fishing vessel headed to Alaska, said the bottom outlet kept plugging and he needed a safe way to gravity-drain the waste because the pump had failed and no vacuum service was available locally. Ted Mooney replied that sulfuric acid is not safe for stainless steel because it is too corrosive. He instead pointed toward caustic soda as a possible alternative, though the excerpt does not include detailed instructions or confirmation that it would solve the clog. The practical takeaway is that the proposed acid treatment risks damaging the tank, so a different approach is needed for clearing the blockage and emptying the tank safely.
Q. I am on a fishing vessel headed to Alaska. We have a stainless steel vented tank approximately 400 gallons. The tank holds the waste from our toilet including toilet paper and flushable baby wipes. The pump to empty the tank broke and we are trying to empty the tank though gravity out a fitting on the bottom. Is it safe to introduce sulfuric acid to dissolve the paper products in order to let the liquid flow freely out the bottom. Presently the 2″ pipe fitting just plugs up with the paper products mainly the flushable wipes. Can anyone help with this mess? We checked for businesses that suck out portable toilets and there are none that we know of as it is a fairly remote town. Thanks for any help. Just want to be safe in whatever we do.
Ken Yada
– Newport, Oregon, USA
January 18, 2022
A. Hi Ken. sulfuric acid is not safe to use on stainless steel; it is too corrosive. caustic soda ⇦liquid caustic soda in bulk on
Amazon [affil link]
(Draino, Liquid Plumber, Red Devil Lye) will be as effective or more effective at dissolving everything, while not endangering the stainless steel. Never mix acid and caustic, and wear gloves and eye protection. Safe travels and happy hunting.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
January 2022
Just want to thank you for your reply to my question. You have set up a great website. Thanks so much Ted. Simple, honest, accurate information and being able to hear it straight from a human seems rare these days. Thank you again for the information.
Ken Yada
Fisherman – Portland, Oregon
January 31, 2022