Note: if you're using one of those stinky blue treatments that contain formaldehyde or other disinfectants, this post isn't about you. But you would be better served by different treatment, practically anything.
Raritan Engineering markets CP as a no-scrub bowl cleaner that is compatible with KO and other biologically active holding tank treatments. In my limited experience, it seems to be a good product. Sure enough, all home toilet products contain some manner of disinfectants (bleach or quaternary amines), which are exactly the wrong thing for holding tank. We are trying to to encourage a healthy aerobic culture, not bomb it with biocides. They are what the home market requests. In fact, you'll be hard pressed to find a cleaning product that doesn't contain some biocide in the formulation, other than borax or washing soda.
However, I've been playing with regular use of other products in the bowl (ODORLOS, Camco TST, CAMCO Enzyme) to control raw water stink and reduced staining, and they all seem to work quite well. They do not contain surfactants or cleaners per se, but they seem to get the job done. I've also done some side-by-side testing in holding tanks that suggests that adding all of the tank treatment at once doesn't give the best long-term odor control, not for sailors that only pump out a few times a year. The active ingredients (nitrate or enzymes) simply don't last that long; they are consumed or biodegraded, and the tank begins to stink again. Yes, I understand that more frequent pump-outs and treatment are recommended, but in the real world that's a fiction. Judging from the light traffic at the pump-out stations in my harbor, it ain't happening. There are several thousand docked in Deale, one of the Chesapeake Bay's few zero discharge zones.
It seems more reasonable for those that rarely pump-out to add a fresh dose, just a small amount, each time the boat is used. The easiest way to do that, and a way to get double value, is to keep a squirt bottle near the head and give her the small dose each time, perhaps just before leaving, so that it can control saltwater bowl stink as well. I would still add 30 to 50% of the recommended dose with the first use of the head after pumping out.
Since the hoses will see the treatment more often, perhaps permeation risk is somewhat reduced. Probably this is irrelevant.
Boats with vent filters don't typically use holding tank treatment chemicals. Using a bowl cleaner that reduces sulfide generation in the holding tank would have the potential to extend that filter life.
Any downside?
* It's one more thing to remember, but not if you clean the bowl once in a while anyway.
* I can't see how any of these treatments would do any harm, left sitting in the bowl for extended periods. I'm assuming that there is some water left in the bowl.
* If you buy a powdered treatment (the ones I described are available both as powder and liquid) you might dissolve it in water first for convenience. Wouldn't have to; a teaspoon would give a reasonable weekly dose.
* You'll end up using more treatment chemical than recommended, but if you're pump out interval is months, you won't be using any more than you need.
I renovated the 14-year old system on my boat this summer; it's as pristine as my house and I'd like to keep it that way. This seems to be working.
Raritan Engineering markets CP as a no-scrub bowl cleaner that is compatible with KO and other biologically active holding tank treatments. In my limited experience, it seems to be a good product. Sure enough, all home toilet products contain some manner of disinfectants (bleach or quaternary amines), which are exactly the wrong thing for holding tank. We are trying to to encourage a healthy aerobic culture, not bomb it with biocides. They are what the home market requests. In fact, you'll be hard pressed to find a cleaning product that doesn't contain some biocide in the formulation, other than borax or washing soda.
However, I've been playing with regular use of other products in the bowl (ODORLOS, Camco TST, CAMCO Enzyme) to control raw water stink and reduced staining, and they all seem to work quite well. They do not contain surfactants or cleaners per se, but they seem to get the job done. I've also done some side-by-side testing in holding tanks that suggests that adding all of the tank treatment at once doesn't give the best long-term odor control, not for sailors that only pump out a few times a year. The active ingredients (nitrate or enzymes) simply don't last that long; they are consumed or biodegraded, and the tank begins to stink again. Yes, I understand that more frequent pump-outs and treatment are recommended, but in the real world that's a fiction. Judging from the light traffic at the pump-out stations in my harbor, it ain't happening. There are several thousand docked in Deale, one of the Chesapeake Bay's few zero discharge zones.
It seems more reasonable for those that rarely pump-out to add a fresh dose, just a small amount, each time the boat is used. The easiest way to do that, and a way to get double value, is to keep a squirt bottle near the head and give her the small dose each time, perhaps just before leaving, so that it can control saltwater bowl stink as well. I would still add 30 to 50% of the recommended dose with the first use of the head after pumping out.
Since the hoses will see the treatment more often, perhaps permeation risk is somewhat reduced. Probably this is irrelevant.
Boats with vent filters don't typically use holding tank treatment chemicals. Using a bowl cleaner that reduces sulfide generation in the holding tank would have the potential to extend that filter life.
Any downside?
* It's one more thing to remember, but not if you clean the bowl once in a while anyway.
* I can't see how any of these treatments would do any harm, left sitting in the bowl for extended periods. I'm assuming that there is some water left in the bowl.
* If you buy a powdered treatment (the ones I described are available both as powder and liquid) you might dissolve it in water first for convenience. Wouldn't have to; a teaspoon would give a reasonable weekly dose.
* You'll end up using more treatment chemical than recommended, but if you're pump out interval is months, you won't be using any more than you need.
I renovated the 14-year old system on my boat this summer; it's as pristine as my house and I'd like to keep it that way. This seems to be working.