What is your SeeLevel reading when fresh water tank is empty?

[rich.dev]

We always fill up the fresh water tank and use the water pump, even at campgrounds. I always have the front of the trailer slightly raised and still experiencing cavitation and it's always at approx. 13% per the SeeLevel monitor, same as @GarryandKristi POST  from HOW TO: Fresh water tank suction tube mod - NO SPIN WELDING REQUIRED. thread! I'm hoping it's the SeeLevel monitor that's not accurate, however, sounds like when Garry drained the fresh water tank with front raised, approx. 5gal drained, that's pretty close to 13% of 32gal! 

I have not checked the water tank level at 13% or done any tests by doing the bucket test, just wonderring what others are experiencing....what is your SeeLevel reading when fresh water tank is empty? 

[dewdev]

Mine reads zero when the water tank level is empty.

[ScubaRx]

If the sensor is installed correctly and the tank is empty it will read zero percent. 

[MAX Burner]

Our's never gets empty due to the suction tube being off the bottom of the tank - that said, the SeeLevel indicates around 10 -13% (depending on fore/aft angle) as others have mentioned when the water pump starts sucking air.  I can usually drain 4 - 5gal of trapped water under these conditions.

[Patriot]

Every picture tells a story….sitting dead level with an empty tank.

 

Edited Thursday at 12:08 AM by Patriot

[Rolind]

Mine usually reads zero at empty after draining the tank with the low point drain under the curbside  bed. The pump starts sucking air at about 13%. I’m not sure I could reach zero with the pump, never tried. My black reads zero easily, but I need to lift my nose at the dump station to get my gray to read zero at level. 

[Rivernerd]

Our Seelevel fresh water tank reads 0% even before it is empty; it reads 65% when it is full and the overflow drain is running--with the trailer dead level.  So, we have learned to fill it to overflowing, and when it reads 0, we know we still have as much as 35% remaining-- again with the trailer at dead level.

I considered asking Oliver to replace the fresh water tank gauge under warranty, but once we made the mental adjustment, we opted to just deal with it.

For what it's worth, neither our gray or black tank Seelevel gauges are accurate either.  We have learned to deal with it.

[rich.dev]

Thanks all, mine has never registered 0 using the water pump, like I said it will start slurping around 13% and I have had it perfectly level, and the front slightly raised. Only when I drain the tank will it drain to 0. So I’m thinking maybe the suction tube is off the bottom of the tank.  Next time (probably tomorrow/Thursday since it’s shower day) when it starts sucking air I’ll drain it and see how much water is left. 

[rich.dev]

2 hours ago, Rolind said:

Mine usually reads zero at empty after draining the tank with the low point drain under the curbside  bed. The pump starts sucking air at about 13%.

And another one sucking air at around 13%, I was thinking on some Ollies the suction tube is off the bottom of the tank, but then why the magic number of 13%, this has me thinking now! 

[John Dorrer]

I drain my fresh tank to 0. On the flip side the max reading is 88% full and that is after 30 seconds of water pouring out of the overflow valve. 

 

My gray tank shows 13% after draining. If there is slope at the dump I have gotten it down to 0.

 

As far as the fresh, I just add 12 to the fresh tank readout.

[srthomsen]

Mine reads "0"as do all the others when empty.

[rich.dev]

2 hours ago, John Dorrer said:

I drain my fresh tank to 0

John, is this when you use the water pump or when you drain it? Mine also drains to 0, but with the water pump it starts sucking air at 13%. 

My grey and black tanks show 0 after draining/dumping. 

Edited Thursday at 04:13 PM by rich.dev

[rich.dev]

17 minutes ago, srthomsen said:

 

Mine reads "0"as do all the others when empty.

 

Is this when you use the water pump or when you drain it? Mine also drains to 0, but with the water pump it starts sucking air at 13%. 

My grey and black tanks also show 0 after draining/dumping

 

[John Dorrer]

46 minutes ago, rich.dev said:

John, is this when you use the water pump or when you drain it? Mine also drains to 0, but with the water pump it starts sucking air at 13%. 

My grey and black tanks show 0 after draining/dumping. 

When I drain it .

 

[rich.dev]

13 minutes ago, John Dorrer said:

When I drain it .

…….and with the water pump? 

[John Dorrer]

26 minutes ago, rich.dev said:

…….and with the water pump? 

I'm confused on how the water pump figures in on this when draining the tanks.  I didn't understand that conversation.

[rich.dev]

1 hour ago, John Dorrer said:

I'm confused on how the water pump figures in on this when draining the tanks.  I didn't understand that conversation.

Sorry let me clarify John. I always fill up the freshwater tank and use the water pump for everyday use, even when at full hookup campsites. Why I do this is a discussion for another day! 😊 In this mode, when the water pump starts sucking air, the SeeLevel shows still 13% left in the tank. 

On the other hand, when I drain the freshwater tank by opening the valve like in THIS video, it drains 100%, ie SeeLevel shows “0”. This is obviously because the drain point is at the bottom of the tank.
 

So my thinking is the water pump suction tube is off the bottom of my water tank, ie when it starts sucking air there is still approx. 13% water sitting on the bottom, like a few others have noted as well. 
 

Hope this makes sense! 😊

[John Dorrer]

3 hours ago, rich.dev said:

Sorry let me clarify John. I always fill up the freshwater tank and use the water pump for everyday use, even when at full hookup campsites. Why I do this is a discussion for another day! 😊 In this mode, when the water pump starts sucking air, the SeeLevel shows still 13% left in the tank. 

On the other hand, when I drain the freshwater tank by opening the valve like in THIS video, it drains 100%, ie SeeLevel shows “0”. This is obviously because the drain point is at the bottom of the tank.
 

So my thinking is the water pump suction tube is off the bottom of my water tank, ie when it starts sucking air there is still approx. 13% water sitting on the bottom, like a few others have noted as well. 
 

Hope this makes sense! 😊

OK got it. We use our fresh tank 100%. I have never experienced what you stated. I will have to look at ours on our next trip👍

[jd1923]

On 1/29/2025 at 1:12 PM, rich.dev said:

We always fill up the fresh water tank and use the water pump, even at campgrounds.

We do the same. That's what the kool kids do! 🤣

Honestly, I stopped looking at SeaLevel gauges when they did not read correctly in a Class-A we had, in a Class-C, and again in the Oliver. The Oliver is so sensitive to level that you can bring up or down the front jack an inch and the reading may change 10-20%!

We stopped looking long ago, though given this thread I will study this during our trip to the Q this week. We fill the FWT when we hear the pump pulling air, we know our gray tank lasts 3-5 days and a good 10 days on the black, so we don't bother with readings that are more often inaccurate. 

Our hull has the suction tube defect. We pull air way sooner than 13%! (more like 44%) We have only 18 gallons usable in our FWT. Good thing we hold another 36-gal in the tank in our truck bed, having 3 x 18-gal for 54-gal total.

I know it's 18 gallons. Every time the water pump pulls air we refill the tank via the boondocking port (good thing I replaced the 1/4" ID brass turn-valves for 12mm ID motorized valves). I measure the refill and after 4-5 times measuring it has always been right at 18 gallons. BTW, measuring the amount it takes to refill, 'til the tank starts to overflow is the ONLY way to determine  the amount filled and the net amount remaining in the tank!

Filling both tanks tomorrow to head out to the Q this weekend. Warming up soon with highs of 80F in the SW valleys next week! 😂

Edited Friday at 08:22 AM by jd1923