Holding tank plumbing

[Omatako]

OK so I'm getting really tired of the odour that keeps permeating my boat after what I reckon is a short time.

I have re-plumbed my holding tanks with what the chandlers around here assure me is the highest grade of sanitary flexible pipe they can supply. For a while, say a year and a bit, the smells are gone and I can invite family and friends aboard without being embarrassed. But then it comes back.

So now I'm thinking of using normal rigid PVC tubing with the associated elbows, bends and other fittings that would normally make up a domestic system. Simply stated, I don't have odours in my home, why should they happen in my boat?

Has anyone any experience with this? Because at the end of it all, a holding tank is somewhat different to a domestic system inasmuch as a domestic system doesn't store the nasties. Is the normal PVC eventually also permeated by the nasties?

Any comments out there?

[RichH]

When was the first time you replaced the duck-bill vent valves in the anti-siphon loop? These small 'rubber' valves ultimately deform enough to allow the free passage of 'gas' instead of fully closing .... many times a bit of crud will form on the face of the 'duck-bill' and hold it partly 'open', easily cleaned.

[erps]

There was a fellow who posted pictures of his PVC pipe job a week or two ago. He thought that it did a good job at reducing odors. It was pointed out by some others that a completely rigid installation might create another batch of problems. I'm considering a partial PVC installation with the softer hose connectors here and there so the whole thing can move a little bit.

[ereiss]

You might want to post your question over at expert forum that Peggie Hall provides at The Head Mistress - SailboatOwners.com

She is the expert on all things "head".

I apologize to Sailnet for sending you to another site, but you need to go to where the expertise is.

regards,

[erps]

http://www.sailnet.com/forums/gear-m...tml#post681348

[Omatako]

Thanks for the link Ray, that post had slipped back three pages since I last had a chance to look at the board and I don't normally bother going that far back. Thanks also to Cotemar for sharing his experience, gives confidence.

That sort of does it for me, I'm going to convert mine to rigid pipes. I don't have to worry about ABYC

[CaptainForce]

There is an added technique to reduce odors. Aerobic bacteria produce far less obnoxious smells than anaerobic bacteria. There are two steps to encourage the growth of aerobic bacteria in your holding tank. Add a second vent line to the tank if a fitting is available and preferably on the opposing side of the boat. Make sure these vents are keep clear and open. Second, do not put anything in your tank such as chlorine or other toxic chemicals that would kill the bacteria population. With a heathy aerobic microbe population producing mostly carbon-dioxide and water from your wastes, you may not find a need for any other plumbing changes. Take care and joy, Aythya crew

[Minnewaska]

If you think about it, adding hard pipe to a system that continues to smell, is only intending to hold the smell back, not correct what is causing the smell. That has to eventually fail as well, may take longer.

If you know you are starting with clean lines (including the discharge and vent lines), then there are only two things you need to do to fix this. Keep bacteria killing stuff out of your tank and maximize the vent line. Even the standard idea of putting oil in your head to lubricate the pump, will kill the good bacteria in your holding tank. Google up Peggy Hall, she explains it all.

[sailingdog]

Are you sure it is the hoses that are causing the odor? You might be doing a lot of work to fix the wrong part of the system. Have you checked the hoses using the rag soaked in hot water to see if they're permeated? If they aren't then the odor cause is probably something else.

I'd highly recommend getting Peggie Hall's book, which talks about the most common causes of odors on a boat and how to solve them.

[Ramin]

the boatbuilding.community - Marine Sanitation: Fact vs. Folklore

I know I'm a newbie, but I have also been looking into this. I cam across this info that might help. You will notice that part way down they explain that solid PVC is possibly one of the worst mistakes you can make.

Hope it helps you make a good informed decision.