Tank capacities

I'm sure there are any number of answers to this but for me, knowing the size of the holding tanks absolutely had something to do with purchasing our 5.0TA, had they been much smaller I would have passed on it.
 
I have received quite a few comments on my post about tank volume, some positive, some negative. Thank you all for your opinions. This morning I measured my tank; it measures the same as Mark B1's and correlates to a 28 US gallon capacity. HOWEVER, I redid the test, this time using a different water container, one with a stated capacity of 2.5 US gallons ( to a measure mark). At 20 US gallons I had water backflowing from the floor drain in the bathroom. Anyone got any ideas of why a 28gallon tank will only hold 20 gallons?? The trailer was dead level, and the tank was dead empty!
 
I have received quite a few comments on my post about tank volume, some positive, some negative. Thank you all for your opinions. This morning I measured my tank; it measures the same as Mark B1's and correlates to a 28 US gallon capacity. HOWEVER, I redid the test, this time using a different water container, one with a stated capacity of 2.5 US gallons ( to a measure mark). At 20 US gallons I had water backflowing from the floor drain in the bathroom. Anyone got any ideas of why a 28gallon tank will only hold 20 gallons?? The trailer was dead level, and the tank was dead empty!

How did you ensure it was 'dead empty'?

Where are you pouring the water in?
 
I have received quite a few comments on my post about tank volume, some positive, some negative. Thank you all for your opinions. This morning I measured my tank; it measures the same as Mark B1's and correlates to a 28 US gallon capacity. HOWEVER, I redid the test, this time using a different water container, one with a stated capacity of 2.5 US gallons ( to a measure mark). At 20 US gallons I had water backflowing from the floor drain in the bathroom. Anyone got any ideas of why a 28gallon tank will only hold 20 gallons?? The trailer was dead level, and the tank was dead empty!

Does the floor drain stick down into the tank or is it flush to the surface? What I am getting at is, could there be any air trapped at the top of the tank when it is "full"?
 
There appears to be something strange going on here. The grey tank on my 5.0TA is also listed at 28 gallons. At the end of my last trip (last summer), all tanks were emptied. The readout on my tank sensors showed the fresh and black tank empty, but the grey tank full. Thinking that there was grease on my grey water sensors (they are Horst, sent to ETI before ETI was installing them as standard), I filled the grey water tank bu using 4-1gallon jugs and added 2 cups of Dawn dish detergent. I put 26 full gallon jugs down the sink without having any flow up into the shower. I connected the trailer to the truck and hauled it somewhere around 60 miles (100 km) and then drained the grey tank. The readout still showed it to be full. Then I read that you should let the detergent sit overnight. So I repeated the process again, filling and dumping 26 gallons down the sink and added another 2 cups of dawn, again without overflow. I let it sit for 4 days before draining. Once again, the sensor panel indicated it was full. I finally gave up and called ETI and spoke with Dustin in parts. He said that they would have attempted to clean the sensors the same way, and given the results, he was certain it was the sensor panel itself. Unfortunately, ETI had switched panels, but I called the company and a company rep told me the circuit boards do not fail often, but it does happen. I paid $15 for a new board, installed it, and with my fingers crossed, pressed the test button and voila, the grey tank now indicated empty. So glad it was not a wiring problem with the tank probes. However, I am sure that the advertised capacity of my grey tank is accurate at @ 28 US gallons. Can’t say the same for the black and fresh tanks because I haven’t had any reason to check them.
 
Yes, the number of people who think you never have a need for math or science after high school worries me too.

What worries me more is the number of people who apparently didn’t learn very much math or science when they were in high school!
 
I can say with absolute undeniable certainty - my grey tank is not as large as I would like - no matter how you measure it!
--
Alan
 
2018 19' tank sizes

Our 2018 19' advertised and measured water tank sizes are:

advertised measured
28gal 25.7gal fresh
26gal 20.5gal gray
19gal 13.0gal black

At 13 gallons, the black tank will overflow into the gray tank. I posted on this here and here

I measured with a 1-gallon milk container, adding until the fresh overflowed out the fill tube and gray overflowed into the bath floor. Trailer was level.

Bill R
 
I can say with absolute undeniable certainty - my grey tank is not as large as I would like - no matter how you measure it!
--
Alan

Agreed. One way we manage our grey water is by dumping our used dishwasher down the toilet. Less water going into the grey tank & soapy water in the black tank to keep it “clean”. :whistling:
 
WE have had numerous aux fuel tanks on our trucks over the years and not one has held the claimed amount of fuel. Most are off by about 5%
 
From how it was explained to me , the tank is mounted between the frame cross braces and the top of the tank is flush with the bottom side of the floor
The drain piping is run below the frame and enters the tank on the side so not all of the tank volume is useable..
Secondly the drain piping from the grey tank to the drain valve enters the grey tank on the side (slightly up from the bottom) so even when you drain the tank completely there is still water trapped in the tank
I really don’t understand why this is such a big issue ?
If one or two gallons is the straw that broke the camels back then I have no answer !
 
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From how it was explained to me , the tank is mounted between the frame cross braces and the top of the tank is flush with the bottom side of the floor
The drain piping is run below the frame and enters the tank on the side so not all of the tank volume is useable..
Secondly the drain piping from the grey tank to the drain valve enters the grey tank on the side (slightly up from the bottom) so even when you drain the tank completely there is still water trapped in the tank
I really don’t understand why this is such a big issue ?
If one or two gallons is the straw that broke the camels back then I have no answer !

Exactly!, Fish are not biting, cotton is down and now I have to be worried about capacity. ?
 

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