Pump out only removing about 1/2 the aft tank contents?

Gdindy

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Jul 11, 2007
44
Hunter 410 Washington Park Marina, Michigan City, Indiana
I have a 2001 410, I'm 3rd owner. Previous owner told me they usually used front head most of time and now I know why. When at pump out I can only remove about 1/2 of the contents. We do not put paper down bowl and in three years have only used for #1's.
When tank is 1/2 empty following pump outs we get absolutely no odors, when it becomes full of course we get some smell both outside and in. We have a Eco Vac electric toilet which appears to work very well. I have shot water into the vent from the outside and used a screwdriver to try and reach any blockage. I will try to remove the vent and as some have done on the forum drill a hole into the screen or soak in some lime away or white vinegar to eliminate any blockage. I notice when I pump the front head and flush with clean water for a rinse from the hose I actually hear a whistle sound from the vent due to the internal pressure from the water filling the tank . When I pump the back tank and flush until full I hear nothing and get barely a trickle if anything from the vent hole when the holding tanks becomes full with clean water to do a rinse? Any suggestions and thanks in advance.
 
Feb 2, 2006
470
Hunter Legend 35 Kingston
How do you know it's 1/2 empty/full? Do you have a gauge? or are you checking some other way?
 
Dec 2, 1997
8,966
- - LIttle Rock
For openers, I have the same question: how do you know that pumpout is only removing half the tank contents? If you have a tank level indicator, that your toilet is an Ecovac (compact version of a VacuFlush),it's most likely a SeaLand Tankwatch III...the senders are highly prone to becoming clogged with the animal fats in waste (yes, in urine too!). Which brings me to...There's absolutely NO reason to restrict the use of any marine toilet to urine-only...and even less reason not to flush toilet paper. Read and FOLLOW the toilet's instructions for use and maintenance and you won't have any problems.
When tank is 1/2 empty following pump outs we get absolutely no odors, when it becomes full of course we get some smell both outside and in
No...NOT "of course" you have odors. You have odors because the vent isn't allowing enough air exchange with the gasses in the tank to keep the tank aerobic--and therefore odor free--once the tank contents rise high enough in the tank to exhaust the air that's in it.

I have shot water into the vent from the outside and used a screwdriver to try and reach any blockage. I will try to remove the vent and as some have done on the forum drill a hole into the screen or soak in some lime away or white vinegar to eliminate any blockage.
None of which, with the possible exception of using a screwdriver to scrape out the vent THRU-HULL will accomplish anything at all. You've joined this forum 9 years ago...if I've posted instructions for clearing a blocked tank vent once in the last 9 years, I've posted 'em a dozen times....and I've written two books that include those instructions. ...yet you don't have a clue about how to clear a holding tank vent???? Your toilet has an owners manual...if the PO didn't leave it onboard, it's readily available from the mfr...yet you've never bothered to learn how to use your toilet as it's designed to be used either.

Both your holding tank vents are at least partially blocked. Find the instructions for clearing holding tank vents...follow them exactly. If you find filters in the vent lines, remove them. Call SeaLand (they now answer the phone "Dometic") 800-321-9886 and ask them for the owners manual for your toilet....and read it!

And after you've done that much, if you still have questions, I'll be glad to answer 'em.
 
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Jan 12, 2011
930
Hunter 410 full time cruiser
On my 410 the forward head always says it is 3/4 full by the gauge (and it's always empty because we don't use it)and the aft head is always empty not matter how much is in it. If you think is is 1/2 full after pump out just put the mattress out of the way, take the over over the tank off, and shine a light along the side and if it is 1/2 full you will be able to see it.

The level system doesn't work worth crap!

BTW - the forward head discharge hose hold over 1/2 gal because it goes to the top of the tank. It's a bad design and if you use it a lot the cheap hose if going to get bad because there is no way really to flush that out each time. Just something to think about since it took me 6 hours to change the hose when mine went bad and I didn't normally even use that head..
 
Dec 2, 1997
8,966
- - LIttle Rock
Waste has to enter the tank on--or at--the top of the tank. However, the toilet discharge line can be run to make it a downhill run all but the first 2-4 feet. That should be an easy modification that doesn't require replacing the entire hose. Meanwhile, it's not necessary to leave waste sitting in that hose...follow the flush with clean fresh water to rinse out the hose behind the flush....leave CLEAN water sitting it. However, if two toilets at opposite ends of the boat are connected to the same tank, one of 'em is waaaaaaaaaay too far from the tank. The BEST solution is a second tank for that one.

As for your tank level indicator...it's not the device that's a piece of crap...the sender is coated with it. Internal senders have to be removed every couple years to clean 'em. A better solution: replace it with one with a sender that goes on the outside of the tank. Profile Tank Monitors The "Solo" is a single tank monitor. If yours is a SeaLand Tankwatch, the same wiring will work with it.
 
Jan 12, 2011
930
Hunter 410 full time cruiser
Waste has to enter the tank on--or at--the top of the tank. However, the toilet discharge line can be run to make it a downhill run all but the first 2-4 feet. That should be an easy modification that doesn't require replacing the entire hose. .
Not if the top of the holding is 3 feet higher that the head.

I don't question your experience and knowledge in the general area of these systems, wondering about specific boat models and their construction.
 
Dec 2, 1997
8,966
- - LIttle Rock
Not if the top of the holding is 3 feet higher that the head.

I don't question your experience and knowledge in the general area of these systems. Please do the same for specific boat models and their construction
You actually think that after 25 years in marine sanitation I wouldn't have any experience with specific models and what passes for system design (mostly awful) in most of 'em? 3' IS doable...but may be more trouble than it's worth to you.
 
Feb 26, 2004
23,085
Catalina 34 224 Maple Bay, BC, Canada
I don't question your experience and knowledge in the general area of these systems. Please do the same for specific boat models and their construction.
Whoosh.

Bad form to question the person who knows everything there is to know about these things, as well as the bumblers who designed specific boats.
 
Jan 12, 2011
930
Hunter 410 full time cruiser
since I said that I assume this is just another internet case the need to "win"
 
Feb 26, 2004
23,085
Catalina 34 224 Maple Bay, BC, Canada
But if you think she doesn't go off on people in her replies sometimes you haven't read enough.
Gentlemen, it appears that there may be a misunderstanding here. I commented on the difference between system knowledge and specific boat awareness and installation details. I would never use your own phrase Don, about learning to read. What I would offer is to go back and reread what has been typed. Like this:

as well as the bumblers who designed specific boats.
She points out, in many cases, that the original boat builders didn't have a clue when it came to plumbing systems. I don't find that the least bit untrue.

I'm not and have never claimed to be an "expert", Don, I just try to share what I know and the information I've "collected" from many reputable sources, and as many know, I share those very often with links.

You may also note the term RTFM. F stands for Funny. It is altogether true that many folks don't do that. In many of her replies, Peggie simply explains that many problems that are reported could well have been avoided by doing just that. I also find that not unreasonable.
 

Gdindy

.
Jul 11, 2007
44
Hunter 410 Washington Park Marina, Michigan City, Indiana
Sorry everyone did not mean to start Poop War 3 only needed some advice on what might be happening. Thank you all for your assistance, I will contact mfg I do have the online manual but nothing I have found in it about clearing the vent.
 
Dec 28, 2010
462
Catalina 380 san pedro
Peggy, The best money we have spent on the new to us boat is the money we spent buying your book. I'm in the process of procuring the new fittings and hose to replace the inadequate 1/2" vent hose with a larger hose and new fitting. Of course the fitting is a right angle fuel vent. I read the portions of your book out loud to the admiral and she simply stated " ok, just do it then." We also are planning to clean out the holding tank. I bought two gallons of tide this morning and already have the ice getting nice and cold in the freezer. I'm pretty sure that is why the gauge ( a tank monitor system) always indicates 1/2 full even after a pump out. We have eliminated all of the odors in the boat except those due to the small vent and are looking forward to keeping it the boat odor free. Thanks for sharing your expertise.:thumbup:
 
Dec 2, 1997
8,966
- - LIttle Rock
We also are planning to clean out the holding tank. I bought two gallons of tide this morning and already have the ice getting nice and cold in the freezer. I'm pretty sure that is why the gauge ( a tank monitor system) always indicates 1/2 full even after a pump out.
That may not be enough to clean the gunk off the tank sender...you'll prob'ly have to remove it to clean it. Before I'd do that, I 'd replace it with one that has senders on the outside of the tank.

We have eliminated all of the odors in the boat except those due to the small vent and are looking forward to keeping it the boat odor free
If you still have any odor inside your boat, replacing the vent thru-hull to increase ventilation to the tank won't solve it. Page 53 in my new book: ....the tank is rarely if ever the source of odor INSIDE the boat. Why? Because unless the tank is leaking, odor from inside the tank has only one place to go: out the tank vent! So while frequent pumpouts, increased ventilation, various tank products may or may not have any impact at all on odor out the tank vent, using any or all of them to try to eliminate odor inside the boat is only chasing your tail …you’ll never catch it. So you need to find the real source and eliminate it.
 
Dec 28, 2010
462
Catalina 380 san pedro
I should have clarified what I meant about the last of the odors. it's only happening when we flush and the odor seeps out of the vent. Our poor dock neighbors thought it was their boat that was so odorific. I'm trying to do everything possible to not have to pull the sender out of the tank and also not have to remove the tank for cleaning, but am prepared that if I have to .....I will. We started using KO in the tank when we bought the boat a couple of months ago. I still want to give the tank a cleaning with the tide and ice cube treatment. Then at least I will have tried everything short of tank removal and heavy duty cleaning. I'm quite sure if all else fails I can get a new tank easily enough. The whole working on the waste tank reminds me of Bill Murray cleaning the pool in Caddy Shack. I'll get myself all dressed up in a white protective suit. Thanks again Peggy.:waycool:
 
Dec 2, 1997
8,966
- - LIttle Rock
Until you improve the ventilation to the tank, K.O. prob'ly isn't getting enough oxygen to work aerobically, which is essential in eliminating odor. But you shouldn't have to replace the tank to accomplish everything you NEED to accomplish. I'll be glad to help you do that.
 
Dec 28, 2010
462
Catalina 380 san pedro
That's why I want to put a bigger 1" vent hose on the tank. Of course in all fairness to Catalina, the previous owner was a live aboard and did not take care of the tank. I even found "DRANO" in the head. I have made great strides thanks to your help in eliminating odor inside the boat and I think with a few more days of work I'll be home free. As I said, the book is an amazing reference.
 
May 21, 2013
45
Hunter 410 Stuart
Hi,
I own an 1999, H410 with very likely the same installation. We had the problem, that we could empty only about 1/2 of the aft holding tank. There were two reasons for tat:
1. The vent hose was clogged. I replaced the whole hose. If you continue with a clogged vent hose, you might collapse the holding tank from a too high underpreasure during the pumpout process. Since all the covers underneath the bed were already removed, I decided to replace the 1 1/2" sanitation hose for the pumpout as well. It caused me only about one additional hour of work.

2. There was a lot of hard residual in the tank. We tried to break it down with different chemicals. It did not work out properly. So I opened up the cover with the sensor unit, and sucked out the whole crap by connecting a hose on the suction side of the nearby macerator. While running the macerator, I flushed a lot of water in the tank to help washing things away. At the same time, I cleaned the sensorhousing. Now I understand, why these internal sensors do not work for long... Finally, I whent wit an external foil sensor.

Now, the punpout works just fine and we have no odors anymore.
The job is pretty messy, but it's worth to go through it and spend the half day of work on it. The last thing you wanna have, is a toilet / holding tank which is destroxing your precious time on the water.
Good luck
Marco
 
Dec 2, 1997
8,966
- - LIttle Rock
2. There was a lot of hard residual in the tank. We tried to break it down with different chemicals. It did not work out properly. So I opened up the cover with the sensor unit, and sucked out the whole crap by connecting a hose on the suction side of the nearby macerator. While running the macerator, I flushed a lot of water in the tank to help washing things away.
I do wish you'd asked questions before you did this, 'cuz there wasn't any need to open the tank to clean it out...you just didn't try the right chemicals dissolve the sludge. Or that putting water into the tank via the deck pumpout fitting sends the water to the bottom of the tank to stir up sludge and hold it in suspension so it can be pumped out or pulled out with the macerator pump.

You can make sure your vent never becomes blocked again by replacing the vent thru-hull with an open bulkhead thru-hull that you can stick a hose nozzle up against to backflush the vent line every time you wash the boat.