Holding Tank Pumpout -- "Rinse" Port?

[jeepbluetj]

I own both a Motorhome (caravan with an engine, whatever you non 'mericans call that) and the boat.

Both have holding tanks. I typically do the rinse back down the deck fill thing on the boat. On the motorhome I have one of these:
http://www.amazon.com/Camco-40126-To.../dp/B000BUU5TU

I just had to be up to my elbows in waste moving the macerator on the boat. That was indeed a shtty job. I have already replaced all the hoses.

The motorhome has FAR less smell than the boat. I attrubute that to:
1. I use the rinser every time I dump, and leave 2-5 gal or so of fresh water in it when I store it.
2. It has a much bigger vent (1.5 inch vs .75 inch for the boat)

[Dockhead]

Originally Posted by jeepbluetj

I own both a Motorhome (caravan with an engine, whatever you non 'mericans call that) and the boat.

Both have holding tanks. I typically do the rinse back down the deck fill thing on the boat. On the motorhome I have one of these:
http://www.amazon.com/Camco-40126-To.../dp/B000BUU5TU

I just had to be up to my elbows in waste moving the macerator on the boat. That was indeed a shtty job. I have already replaced all the hoses.

The motorhome has FAR less smell than the boat. I attrubute that to:
1. I use the rinser every time I dump, and leave 2-5 gal or so of fresh water in it when I store it.
2. It has a much bigger vent (1.5 inch vs .75 inch for the boat)

I have, thank God, and touch wood, never had the slightest smell from my sanitation system, other than when I've got it apart working on it.

I think it's because the system is rather well designed. The vent is 1 1/2", and it goes through the topsides not far from the waterline. I don't think it has filter on it. All the hoses are quality sanitation hose, and double-clamped.

[Stu Jackson]

The critical key is the size of the vent line.

All discussed in Peggies' excellent book.

[Kalinowski]

I've been told that murcuric acid is great to clean out the sludge and salt buildup in the waste system. Any comments?

[Dockhead]

Originally Posted by Kalinowski

I've been told that murcuric acid is great to clean out the sludge and salt buildup in the waste system. Any comments?

I believe you mean muriatic acid, which is hydrochoric acid. Potent stuff. I'm not sure what parts of your sanitation system this would dissolve, probably many.

[Hudson Force]

In addition to the size of the vent, dual vents can improve the aerobic population of microbes in the holding tank. It's anaerobic digestion that is responsible for more obnoxious odors and forming a "cross" ventilation over the greater surface of your holding tank promotes aerobic digestion.

I don't find the rinsing as needed to prevent a "sludge" accumulation in the tank. There's enough agitation from the activity of my boat to keep solids suspended when emptying my tank.

Some consideration for the benefit of the rinse can be related to the design of the system. I don't use a Y-valve, but draw from an open T-fitting to the deck pump out or the macerator.






This rough sketch does not show the two separate vents as I described and the "T" spliting to the Macerator and deck plate draws from the bottom of the tank, but exits at the top above the level of the macerator and below the deck plate. I usually flush a brief fresh water rinse down my deck pump out plate after pumping out so I'm left with fresh water in the macerator. I find that uric acid in the macerator can corrode the stainless steel bolts within the macerator housing and shorten it "lifetime".

I see the muratic acid comment added while I was writing this post. I'm quite sure that this stronger acid would be just as harmfull, if not more so, if it was left sitting in a macerator pump.

[Dockhead]

Originally Posted by Stu Jackson

The critical key is the size of the vent line.

All discussed in Peggies' excellent book.

I bet the length of it plays a role, too. Mine is less than 2 meters long.

[boeing1]

after I pump out I flush tank with fresh water and also the head. them pump out again, has worked well for me so far.
any extra hoses or fittings me end up being a problem.....

[brownoarsman]

Any tips for getting everything out? Pumpout always seem to leave me with a couple inches left where the pumpout hose fits at the bottom of the tank.
I believe it may be because it is losing vacuum to the head with the three way switch drawing from the head to the holding tank, but after reading CF, I've been too terrified of Florida FWC to try switching the three way to overboard discharge when pumping out!


Sent from my iPhone using Cruisers Sailing Forum

[Hudson Force]

Originally Posted by brownoarsman

Any tips for getting everything out? Pumpout always seem to leave me with a couple inches left where the pumpout hose fits at the bottom of the tank. ............

As someone else posted earlier, I don't see any reason to remove everything from the tank. It's most common to continue using the tank following a pump out. In the case where there's an expectation to open the system in order to change hoses and fittings I can understand where someone would partially fill and rinse a couple times at the pump out station.

[rwidman]

Originally Posted by brownoarsman

Any tips for getting everything out? Pumpout always seem to leave me with a couple inches left where the pumpout hose fits at the bottom of the tank.
I believe it may be because it is losing vacuum to the head with the three way switch drawing from the head to the holding tank, but after reading CF, I've been too terrified of Florida FWC to try switching the three way to overboard discharge when pumping out!


Sent from my iPhone using Cruisers Sailing Forum

If you imagine a 1 1/2" outlet on the side of the tank at the bottom, you should realize that once the contents reach that level, the pumpout machine or your macerator begins sucking air. There's nothing you can do about it really unless you somehow raise the other end of the tank.

If you listen carefully, you should hear it begin to gurgle when it reaches this point. If the pumpout has a clear sight tube, you will see the intermittent flow at this point.

[brownoarsman]

Makes sense. I was hoping it could create enough of a vacuum that it could get everything out. What I really need is a pumpout hose with a straw!Or to install a holding tank discharge. Two reasons why I want it all out: one, the holding tank pumpout hose has two barbs exposed on its fitting which I'm a wee bit uncomfortable with, two, it's a small holding tank, so that last bit represents about 10% of capacity and an extra couple days before finding a pumpout.


Sent from my iPhone using Cruisers Sailing Forum

[brownoarsman]

One last question, and not to be gross, but is there any way to ensure there's no last dribble around the pumpout hole (besides installing a holding tank drain)? I've been waiting to see the sight tube get frothy, hear the intermittent pumping, then I wait a little more, then I slowly release pressure on the vacuum, but I still always get a little foul-smelling effluent on my deck. It's nasty, how do I avoid it?

[rwidman]

Originally Posted by brownoarsman

One last question, and not to be gross, but is there any way to ensure there's no last dribble around the pumpout hole (besides installing a holding tank drain)? I've been waiting to see the sight tube get frothy, hear the intermittent pumping, then I wait a little more, then I slowly release pressure on the vacuum, but I still always get a little foul-smelling effluent on my deck. It's nasty, how do I avoid it?

The hose is sucking the sewage out just like you might suck on a straw in a glass of iced tea. Turn off the suction and the sewage stops flowing and any remaining in the hose should drain back into the tank. Give it a few seconds after shutting off the suction, then remove the hose.

[brownoarsman]

All the things they don't explain in the YouTube how-to videos! Thanks very much!


Sent from my iPhone using Cruisers Sailing Forum