The waste tank is listed at 17 gal, however it seems to fill up too frequently requiring us to pump out often, was told that it could be a buildup of uric acid that solidifies thus diminishing the holding capacity. A product called Sew Clean was recommended to dissolve the buildup. Anyone have any experience with this product?
Diminished Black Water holding tank capacity
- Thread starter Ted Pinelli
- Start date
I don't.
However, you may want to check the actual capacity.
If you are depending on a tank monitor for level, they notoriously can get inaccurate with age. Especially the ones that use strip sensors outside the tank.
If the tank is actually over flowing in a time perceived as too soon for 17 gallons, it may be that it cannot be fully emptied due to a common design issue with outlet being at the bottom and not having a pickup tube. This will leave a couple gallons at the bottom and is normal. Or, the vent may not be at the top, further diminishing capacity.
An easy way to test it is to go to the pump out and empty the tank, then use a 1 gallon water jug and fill it with the hose while timing the duration to fill with a stop watch like on your phone or use your watch.
Then with the minutes/seconds per gallon rate noted, and the rate preserved because you didn't turn the water off, fill the tank at pump out deck fitting while timing it. Then do the math.
Or you could just count how many jugs it will take.
Just fill it till you hear that telltale increase in gurgle frequency, then you know the tank is full before spilling over or coming out the vent.
However, you may want to check the actual capacity.
If you are depending on a tank monitor for level, they notoriously can get inaccurate with age. Especially the ones that use strip sensors outside the tank.
If the tank is actually over flowing in a time perceived as too soon for 17 gallons, it may be that it cannot be fully emptied due to a common design issue with outlet being at the bottom and not having a pickup tube. This will leave a couple gallons at the bottom and is normal. Or, the vent may not be at the top, further diminishing capacity.
An easy way to test it is to go to the pump out and empty the tank, then use a 1 gallon water jug and fill it with the hose while timing the duration to fill with a stop watch like on your phone or use your watch.
Then with the minutes/seconds per gallon rate noted, and the rate preserved because you didn't turn the water off, fill the tank at pump out deck fitting while timing it. Then do the math.
Or you could just count how many jugs it will take.
Just fill it till you hear that telltale increase in gurgle frequency, then you know the tank is full before spilling over or coming out the vent.
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I suspect it's just a matter of not knowing how many flushes it takes to fill it up. So here's the math: The average flush including waste is .6 gal. The average adult uses the toilet 5x/24 hrs. So that's about 3 gal/person/day. Multiply that by the number of people continuously aboard to find out how many days it should take to fill up your tank. 2 people using a 17 gal tank, will fill up a 17 gal tank in about 3 days.
Learning to use the dry mode to do more than just push the last of the water out of the bowl can add at least another day. I've posted information about how to do that many times in the 15 years I've been here...search this forum for my posts to find 'em. I've also included 'em in my book, along with a lot more useful information (see link in my signature).
Learning to use the dry mode to do more than just push the last of the water out of the bowl can add at least another day. I've posted information about how to do that many times in the 15 years I've been here...search this forum for my posts to find 'em. I've also included 'em in my book, along with a lot more useful information (see link in my signature).
Hi Peggie,
this may not be the right way to ask a question but not used to navigate the forum in detail yet, I try it this way.
I just ordered your book, but like to ask here if a Odor filter is worthwhile? I have one between waste tank and vent, which I found recently during installing an Autopilot. This thing is a couple of years old and recently during a pump out and backflush with freshwater, nasty small spur of brown water sipped out of the Vent. So Iplan to take it out and have the hose direct to the Vent. Any comments are Welcome.
Thanks, Peter
this may not be the right way to ask a question but not used to navigate the forum in detail yet, I try it this way.
I just ordered your book, but like to ask here if a Odor filter is worthwhile? I have one between waste tank and vent, which I found recently during installing an Autopilot. This thing is a couple of years old and recently during a pump out and backflush with freshwater, nasty small spur of brown water sipped out of the Vent. So Iplan to take it out and have the hose direct to the Vent. Any comments are Welcome.
Thanks, Peter
Get rid of the filter and run the vent line directly to the vent thru-hull in the shortest, straightest line possible. And as long as you're doing that, replace the vent thru-hull with an open "bulkhead" or "mushroom" thru-hull (see photo) that allows the air exchange needed to eliminate odor out the vent without a filter. When my book (see link in my signature) arrives, you'll find a detailed explanation in the Chapter "Holding Tank Odor--Odor Out The Tank Vent" beginning on page 46 . And I'm always glad to answer any questions that aren't answered in it.
