Anybody know of any kind of tank monitor that will work on aluminum waste holding tank without having to insert a probe inside the tank. Is there any way to chec k the waste level by tapping on the outside. Any suggestions will be greatly appreciated.

There are some ultra sonic tank level moniters that are used in industry that will do it Omega makes some kinda pricey. Depending on location a simple magnetic float switch will do well they can be set to detect getting full and really full if you use two they caost about $15 each and simple to install through a 1 inch hole. They are absolutely immune to sewerage.

I am having a houseboat built and the manufactuer was telling me that it would have holding tank gauges. From what I had heard in the past, this wasn't the ting to do, due to the sludge eventually makes them stick, however to make a long story short they had gauges that have _meta_l sensors that attach to the outside of the tank. Well low and behold I was at West Marine the other day in Fort Lauderdale, and they had those exact same gauges. Can't remember what they were exactly called, but they are LCD guages measures in 1/4, 1/2, 3/4 increments and are manufactured by some company out in the midwest. All I remember is they had work "snake" somewhere in the name. Either company name or City ???? Call west marine, and I'm sure they can tell you exactly what it is. Good Luck

I am having a houseboat built and the manufactuer was telling me that it would have holding tank gauges. From what I had heard in the past, this wasn't the thing to do, due to the sludge eventually makes them stick, however to make a long story short they had gauges that have _meta_l sensors that attach to the outside of the tank. Well low and behold I was at West Marine the other day in Fort Lauderdale, and they had those exact same gauges. Can't remember what they were exactly called, but they are LCD guages measures in 1/4, 1/2, 3/4 increments and are manufactured by some company out in the midwest. All I remember is they had word "snake" somewhere in the name. Either company name or City ???? Call west marine, and I'm sure they can tell you exactly what it is. Good Luck

Accu-Gage from Snake River makes a holding tank monitor.

Click here for article

I believe Raritan Engineering makes one as well.

That's it. Saw this in action on another houseboat, looks pretty sweet and since everything is on the outside, should keep working over time. I was told thogh that they need to be calibrated once installed Good Luck

The gauges you're describing are the Snake River Electronics AcuGage--and they are excellent tank level monitors. However, the sender can only go out the outside of plastic tanks...they have internal sensors for _meta_l tanks. You'll find some details on the Snake River website at http://www.snake-river.org but they've changed the site recently and it doesn't show much. You'll find a lot more information on this vendor's site (whose prices are also a LOT better than WM's): http://www.boatfix.com/elec/acugage.asp

Since this thread started with a post way last October, I don't know whether the holding tank in the boat you're having built is _meta_l or plastic. If the builder HAS spec'd _meta_l, I strongly recommend that you tell him to use plastic instead. _meta_l is ok for water and fuel, but is not recommended for waste holding because urine is SO corrosive that it typically eats through a weld at seam or fitting within 2-5 years...and turns the tank into a collander in about 10 years. The ONLY material recommended for waste holding is thick-walled--at least 3/8" polyethylene.

If your builder doesn't have a source, send him to Ronco Plastics (you can see their catalog at http://www.ronco-plastics. com)...they make TOP quality tanks for a very reasonable price...OEM price is prob'ly less than he's paying for aluminum.

I bought the Snake River gauges for my boat last year, thanks to a suggestion from Peg. It has worked out great for me, but I also have plastic tanks. I can now monitor both holding tank and freshwater tank. Calibration is very simple - and documentation and instructions were adequate to get the system installed with very little difficulty.