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Author Topic: Cleaning the holding tank:a disgusting story  (Read 3663 times)

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John Langford

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Cleaning the holding tank:a disgusting story
« on: November 27, 2015, 11:03:18 AM »

A warning: sensitive readers should move on the next topic on the message board!

I recently completed an in-the-boat clean out of my 15 year old holding tank. Very worthwhile but not much fun. I took this on as I noticed that the capacity of the holding tank seemed diminished and occasionally the macerator pump seemed to be labouring when I was pumping out the tank offshore. When I opened the tank access port I noticed two things beyond the obvious evidence of recent use. First, the side and especially the sloped surfaces of the tank were covered with a heavy layer of dense but brittle calcium deposit which broke into slabs and detached from the sides of the tank when prodded smartly but carefully with a large screwdriver. Second, there was a significant build up of sand-like sediment along the whole length of the bottom of the tank. This sediment was deep enough that it partially covered the outlet to the T leading to both the deck pump out fitting and the macerator pump.

I set about cleaning the tank. The key tool (beyond long rubber gloves) was a large powerful shop vac with a hose and end fitting that went into the tank access port and still allowed me to manoeuvre it inside the tank. I also needed to make up a prodding and scraping tools hose clamped to a strong but somewhat flexible metal handle that allowed me to first detach and break up the calcium deposits in the distant front end of the tank and pull those calcium chunks and sediment towards the aft end of the tank so I could further break the calcium chunks into smaller pieces and vacuum them and the sediment up. This was the most difficult and unpleasant part of a generally unpleasant chore. Along the way I had to keep pumping more water into the tank as the shop vac seemed to do a better job when the sediment etc. was wet. Several discrete trips to the marina heads on shore with the full shop vac in a wheelbarrow were required. Except for a scrupulous clean up, that's it. At my age, this is not a job I will have to do twice!

When I closed the system up and used the macerator for the first time with only water in the tank I noticed that the chopper made some strange noises as it dealt with smaller chunks of calcium and some sediment that had been inadvertently pushed into the exit lines during the cleaning process. From the sound of it, you would not want to expose the macerator to too much of that stuff.

I will entertain questions but will NOT provide photos:)
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John
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KWKloeber

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Re: Cleaning the holding tank:a disgusting story
« Reply #1 on: November 27, 2015, 12:35:14 PM »

If you rely on the offshore pumpout, from what you describe ITWMM, I'd stick a rebuild kit in it.

kk
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
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Bobg

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Re: Cleaning the holding tank:a disgusting story
« Reply #2 on: December 01, 2015, 10:23:25 AM »

I put a see thru 3" access port on my tank, every fall I do a pump out, and open this port and shop vac the remainder out, rinse it and shop vac it out again,  after reading your post it am glad I do this, also the see through port allows me to use a flashlight and determine how full it is getting.  I did rebuild my macerato,r not to big a job, also if your macerator stops due to something or other,  swap electrical leads and it will run backwards to clear it,  just my 2 cents  :)
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Bob Gatz, 1988 catalina 34, Hull#818, "Ghostrider" sail lake superior Apostle Islands

Ron Hill

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Re: Cleaning the holding tank:a disgusting story
« Reply #3 on: December 01, 2015, 02:05:58 PM »

John : If you've never checked - the hos from the head outlet (has the joker valve in it) has probably collected the same crud (sandy calcium) on the inside walls.
 
Mine was actually coated till the inside passage was down to the size smaller than your little finger!!  Just remove the hose and wack it on the dock a few times and it'll break loose and come out.

A thought

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John Langford

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Re: Cleaning the holding tank:a disgusting story
« Reply #4 on: December 02, 2015, 02:59:40 PM »

Very useful advice Bob; a little prevention as they say. Much better to do a bit each year than take on the job I described.

Ron, I am a a huge fan of regular maintenance of the head itself. I open up and lubricate the pump once or twice a year, change the joker valve regularly and even take off the hose between head outlet and the tank occasionally and smack it on a hard surface to break up the calcium buildup. But as my original post makes clear, my routine did not extend to tank cleaning.
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John
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KWKloeber

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Re: Cleaning the holding tank:a disgusting story
« Reply #5 on: December 02, 2015, 04:27:13 PM »

I open up and lubricate the pump once or twice a year,


A dallop of mineral oil (baby oil) pumped occasionally (monthly - depending on the use factor) will lube the seals and let everything run smoothly.

kk
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
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Roc

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Re: Cleaning the holding tank:a disgusting story
« Reply #6 on: December 03, 2015, 04:12:57 AM »

Be careful of pumping too much liquid oils in the head. Although they will lubricate, what ends up happening is you'll create an oil slick floating on the top of the tank contents, which could create an "anaerobic" condition in the tank (i.e. smelly tank).  You want a flow of oxygen to keep things with an aerobic state.  PH suggests lubricating the pump cylinder with Super Lube.
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KWKloeber

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Re: Cleaning the holding tank:a disgusting story
« Reply #7 on: December 03, 2015, 08:36:51 AM »

Be careful of pumping too much liquid oils in the head. Although they will lubricate, what ends up happening is you'll create an oil slick floating on the top of the tank contents, which could create an "anaerobic" condition in the tank (i.e. smelly tank).  You want a flow of oxygen to keep things with an aerobic state.  PH suggests lubricating the pump cylinder with Super Lube.

Naturally common sense should prevail, as well as keeping a perspective -- if needs uses a dallop during period "n" to keep things running smoothly, that also presumes that during "n" you're also needing to pump out several times -- ipso, no Exxon Valdez Bay oil slick.  Plus, the agitation of pumping tends to emulsify what doesn't stick to the pump guts.  If it's still a concern, douse while flushing the tank with fresh water while pumping out)!  :thumb:

Besides, with no oil slick and all that greenhouse gas escaping the vent....... pretty soon we won't be able to sail (perspective again.)  :D

kk
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Twenty years from now you'll be more disappointed by the things you didn't do, than by the ones you did.
So throw off the bowlines.  Sail away from the safe harbor.  Catch the tradewinds in your sails.
Explore.  Dream.  Discover.   -Mark Twain

mregan

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Re: Cleaning the holding tank:a disgusting story
« Reply #8 on: December 03, 2015, 02:18:26 PM »

I put a see thru 3" access port on my tank, every fall I do a pump out, and open this port and shop vac the remainder out, rinse it and shop vac it out again,  after reading your post it am glad I do this, also the see through port allows me to use a flashlight and determine how full it is getting.  I did rebuild my macerato,r not to big a job, also if your macerator stops due to something or other,  swap electrical leads and it will run backwards to clear it,  just my 2 cents  :)

Bob, what manufacture of access port did you use.  I've been thinking of adding an access port but I'm always afraid it won't seal 100% and I'll get odor escaping it.
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John Langford

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Re: Cleaning the holding tank:a disgusting story
« Reply #9 on: December 08, 2015, 12:06:41 PM »

My access point looks like it was part of the original construction of the tank. The frame of the port is glued into the tank body. The port itself is not see thru. It has over a half inch of thread and screws down very securely. It is not a source of odours.
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Bobg

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Re: Cleaning the holding tank:a disgusting story
« Reply #10 on: December 09, 2015, 11:10:17 PM »

I used a 3" see thru beckson port, bedded it with 5200 I believe, no odors at all, cover screws down on a o ring, really like it, nice to be able to look in tank with a flashlight.  after a pump out in the fall, I spray water in there and vacuum it dry, ya not too pleasant, but easy to do, probably wouldn't have to do any of that, but with the 3" hole, why not
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Bob Gatz, 1988 catalina 34, Hull#818, "Ghostrider" sail lake superior Apostle Islands

DaveBMusik

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Re: Cleaning the holding tank:a disgusting story
« Reply #11 on: February 01, 2016, 06:24:11 PM »

Having RV'd for many years as well, the key was to put a bowl full of water in the tank after pumping out. This kept solids from accumulating quite as much.
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Dave Burgess
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