How do I know when holding tank is full?

[Dupree]

That's probably a total newbie question, but then I AM a total newbie with this stuff. I've never had a boat with a holding tank before and there's no gauge and you can't see through the walls of the tank (thank goodness!).

So how can I tell when it's getting full and needs pumping out? Will the head just be too difficult to pump (grocco)? What happens? I don't even want to imagine overfilling and blowing something up! I don't know if there's an overflow or what (and where would an overflow go anyway?).

Help!

Dupree

 

[BobM]

If you can't see through your tank I suggest you get a gauge...otherwise the first time you find out will be after a crewmember can't flush the toilet properly perhaps screwing things up good. Now imagine having to fix things afterwards.

 

[Jalepeno]

Install a simple tank full level switch and idiot light such as the "TANKWATCH-1"

http://ecatalog.westmarine.com/full.asp?page=343

 

[Peggie Hall HeadMistress]

Yep..you do need help!

That's probably a total newbie question, but then I AM a total newbie with this stuff. I've never had a boat with a holding tank before and there's no gauge and you can't see through the walls of the tank (thank goodness!).

So how can I tell when it's getting full and needs pumping out? Will the head just be too difficult to pump (grocco)? What happens? I don't even want to imagine overfilling and blowing something up! I don't know if there's an overflow or what (and where would an overflow go anyway?).Help! Dupree

If you cannot determine the level in the tank visually, CG regs require a gauge. You can buy a cheap one that only lets you know when the tank is full...or spend a bit more for one that tells how much is actually in the tank. I recommend that approach.

This one is your best choice...http://ferriellosales.com/ A number of people here have 'em and will agree that it's an excellent product and that Dennis Fierello provides the best customer service and installation assistance on the planet. The price is very reasonable, and the product is reliable.

Yes, holding tanks do have a vent...a line coming off the top of the tank to a thru-hull fitting on the hull, prob'ly very close to the toe rail. It is an AIR vent line, NOT an overflow...allowing waste to overflow out the vent will cause it to become blocked, which can indeed result in a burst tank. Your first that the vent is blocked is a toilet that's becoming harder to pump, 'cuz that means the tank is becoming pressurized...so you want to cease using the toilet until the vent is clear again.

The link in my signature here will take you to a comprehensive "marine toilets and holding tanks 101" manual that should help you understand how to use and maintain your system to keep it trouble free. You'll also find a lot of info in the previous threads in this forum. And I'm here to answer questions too.

Btw...if I were you, I'd have the tank pumped out and also thoroughly rinse out the tank before you use the toilet again. Then, if you know how many gallons the tank holds, while you're waiting for the gauge to arrive via UPS, you can get a rough estimate of how many flushes using the following math:

On average, an adult uses the toilet 5x/24 hours...average flush volume: .6 gal. So each person continuously aboard will put approx. 3 gal./day into the tank..a couple will put 6 gals/day into it. So a 20 gal. tank should easily last 3 days without overflowing...a 12 gal tank barely a one-overnight weekend.

So it becomes obvious that you really do need to know how much is in the tank before you leave the marina...are you just one flush away from full, or only half a tank? A gauge that only tells you when the tank is full is legal, but otherwise useless.l.

 

[Guest]

Holding tank

Hi Dupree, our 1991 model boat came equipped with two electric raw water toilets and a 26 gallon SS holding tank; all remain original equipment. As with yours, ours has no way to measure remaining level status. I estimate each toilet consumes about one gallon of raw water per flush and about four flushes per adult per day. During the cruising season with two adults on board I usually empty the tank every other day or so and once a week if solo. The only signal our tank offers as it reaches full is a noticeable thump as the top of the tank expands upward and then the macerator pump will not evacuate the toilet bowl contents to the tank; it just swirls around the bowl.

So far this has worked out well since we purchased the boat in 2002. I suppose a level indicator gauge would help, but alas remains very low on my list of things to add. Likewise an electric anchor wash down pump to replace my bucket with a lanyard, a bow thruster to place less emphasis on my boat maneuvering skills, dinghy davits, electric halyard winch, etc., etc., etc.

Terry Cox

 

[Ron20324]

I was replacing my sink faucet and drain when that balled-lever that pushes the drain stopper up and down came to mind. If I can find a way to install that ball/lever in a tank, it would operate like a railroad semaphore signal.

A friends tank monitoring sytem died when he got to the islands this winter. I suggested a wall stud finder to read tank levels, and he reports it works great.

 

[Guest]

Holding tank

Hi Ron, good idea. Might work for some, but our tank is in a fully enclosed compartment, with access only by removing a large section of sole, a major job.

Terry Cox

 

[sailingdog]

Another option is to install an inspection plate in the top of the tank, if it is accessible. Beckson makes some that have a clear inspection plate, which allows you to check the level of the tank visually. It also gives you a way to clean out the tank if that ever becomes necessary.

 

[RobG]

This looks interesting

Non intrusive install and the sensors are isolated from the contents of the tank. I may go for it since my tank is black with no way to see how full it is either.
http://www.scadtech.com/tank_monitors
The Solo...

 

[Peggie Hall HeadMistress]

Those are the Profile gauges.

Non intrusive install and the sensors are isolated from the contents of the tank. I may go for it since my tank is black with no way to see how full it is either. http://www.scadtech.com/tank_monitors The Solo...

Scad Tech sells 'em under their own private label brand name. They even use the Profile name too. Scad just does the marketing...Dennis provides all the their customer service and tech support.

 

[Dupree]

Wow, thanks! And ...

Thank you all for the help.

I think I will go with Peggy's advice. Now, about rinsing out the tank ... I was thinking that when I pump it out (next time, actually the first time), I could just then put fresh water in the head and pump it through.

Is that a good idea?

Thanks again,

Dupree

 

[Ron20324]

Rinsing the tank

Pumping extra water through the head during, or after, pumping out is always a good idea- especially if the boat will sit before next use. I fill the bowl, adding some tank additive, then have a crew pump while I'm doing the pumpout hose.

Rinsing the tank by hand pump is alot of pumping. You could, after a pumpout, just fill the tank again by hose via the deck pumpout fitting, then pump out again. Before I upped my vent size to 1.25", I'd reverse-flush the vent line by putting the hose over the outside vent. This has the effect of the vent acting as a showerhead at the top of the tank. Now with the 1.25" thruhull, I can just stick the hose (having cut off the metal end) into the vent line a couple inches to reverse-flush.

 

[Scott B]

Thank you all for the help.

I think I will go with Peggy's advice. Now, about rinsing out the tank ... I was thinking that when I pump it out (next time, actually the first time), I could just then put fresh water in the head and pump it through.

Is that a good idea?

Thanks again,

Dupree

Check here for Peggie's "recipe" for cleaning holding tanks

 

[Peggie Hall HeadMistress]

How to rinse out a tank

Now, about rinsing out the tank ... I was thinking that when I pump it out (next time, actually the first time), I could just then put fresh water in the head and pump it through. Is that a good idea?

That's doing it the hard way--and so is your way, Ron...and neither of your methods work all that well. The easiest way..which still requires a little effort:

You don't have to fill the tank to rinse it out. After you've pumped out, put enough water into the tank to cover the bottom to a depth of 3-4"--NOT through the toilet, but via the deck pumpout fitting--'cuz that sends the water into the tank at the bottom to stir up any sludge...water down the toilet comes into the tank at the top and just falls into the tank without stirring up anything.

Pump that out...repeat...repeat...till you're pumping clean water. Then one last time, but this time turn on the macerator or pump a manual diapgragm pump to rinse it out.

If you have a sea water washdown pump, you can rinse the tank at sea, use it to supply rinse water to the tank...put about 4" of water down the deck fitting...turn on the macerator or start pumping the manual pump...keep up both till you're dumping clean water.

This should be done at least 2-3x/season, especially in preparation for winter layup. Backflush the vent EVERY time you pumpout and/or wash the boat.

 

[Ron20324]

Lighten up, Peggy

That's doing it the hard way--and so is your way, Ron...and neither of your methods work all that well.

Peggy, it's a little gutsy and pretty crusty to badmouth someone's offerings just because you don't do it or believe in them. I presented my post because it DOES WORK, and it is EASIER to me than your 3-times pumping. How about just posting your methods and not criticize those you don't agree with, please.

 

[Peggie Hall HeadMistress]

Ron, I'm a crusty gutsy old lady...deal with it. :dance:

 

[catsailor]

Temperature differences are a clear tell in most seasons.

The air above the liquid is generally warmer than the liquid. I even know a fellow that has temperature indicating tape on the the side of the tank. It works amazingly well, for a few-dollar solution.
​

 

[sailingdog]

Ron, I'm a crusty gutsy old lady...deal with it. :dance:

LOL... blunt and to the point... and funny.

 

[Roy10289]

I have used the wall stud finder with good results on my new plastic holding tank. The best gauge for me is as follows. If you think the tank may be full,it probably is, so have it pumped out.

 

[butchrobbins]

That's probably a total newbie question, but then I AM a total newbie with this stuff. I've never had a boat with a holding tank before and there's no gauge and you can't see through the walls of the tank (thank goodness!).

So how can I tell when it's getting full and needs pumping out? Will the head just be too difficult to pump (grocco)? What happens? I don't even want to imagine overfilling and blowing something up! I don't know if there's an overflow or what (and where would an overflow go anyway?).

Help!

Dupree

Normally, it would probably pump out the vent, but in my case the vent was clogged and it forced its way out at the end of the hose at the vent and into my bilge. YUCK! Thank God I only use it for number 1. I now have it pumped out ever couple of weeks and anytime I get fuel-I pump it out.