Septic tank level monitoring

[signal15]

I saw a couple of old posts on this, but no actual comment on buying something and implementing it.  My septic tank filled today.  Luckily I caught it and only got about 3 gallons of poopy water in the basement.  However, I'd like to be able to monitor the level, or at the very least, simply alert on high level.  
 
I've got an Elk, and a Vera.  I figure a float switch or a water sensor hanging in the tank connected to the Elk will give me a high water alarm.  But maybe there's a depth sensor or a distance sensor that I can use with the vera.  
 
Any suggestions?

 

[RAL]

Here is a company that makes a septic tank alarm.  From the looks of it, the sensor doesn't seem much different than the floats that are used with sump pumps.
The unpleasant and perhaps dangerous part will be mounting it in the tank.  Not something I would want to tackle. Lack of oxygen inside the tank can kill you quickly.

 

[signal15]

Check these out:
http://www.maxbotix.com/documents/XL-MaxSonar-WR_Datasheet.pdf
 
I don't really want to open up my tank again, and I know just a whiff will make you pass out and fall face first into the tank.  I figure I'll get one of these, use a hole saw in the manhole cover and mount it, and then wire it into my vera to monitor the distance over IP (via my Wiznet 4-port serial->ip converter).
 
This sensor is $99.  Cheap compared to other stuff I've seen.

 

[RAL]

Those ultrasonic sensors look like a very nice way to sense the level.  And much safer to install through the manhole cover.  I suspect that the distance calibration will be off though, since the "air" space in the tank is not a normal air mix.  I think you will need to measure the initial level of the tank and compare that to the distance the sensor reports, and then adjust the readings from there.
 
Is the input pipe to your septic tank above the floor level in your basement, or is it below floor level?  If it's above floor level, I'm thinking you could put an ultrasonic sensor in a vertical extension off of the main horizontal pipe and use it to measure when liquid backs up into the vertical extension.  That would allow you to keep everything indoors.

 

[Desert_AIP]

Does your septic tank not have a float and alarm?

 

[signal15]

Those ultrasonic sensors look like a very nice way to sense the level.  And much safer to install through the manhole cover.  I suspect that the distance calibration will be off though, since the "air" space in the tank is not a normal air mix.  I think you will need to measure the initial level of the tank and compare that to the distance the sensor reports, and then adjust the readings from there.
 
Is the input pipe to your septic tank above the floor level in your basement, or is it below floor level?  If it's above floor level, I'm thinking you could put an ultrasonic sensor in a vertical extension off of the main horizontal pipe and use it to measure when liquid backs up into the vertical extension.  That would allow you to keep everything indoors.

 
It's above the floor, it comes in through the wall 7 feet above the floor.  However, there's no good place to put a sensor in the pipe in the house since any vertical stuff is at 45 degrees.  Plus, I definitely don't want to mess with the pipe at all.
 

Does your septic tank not have a float and alarm? 

 
 
Nope.  It's not required by code here, so pretty much no one has them.  In fact, I've never seen one here unless it was a community one.
 
I know that it's not normal air in there, and that the sensor probably will not be accurate.  However, I believe the atmosphere is denser than air, so it should read low, which is better than it reading high.

 

[kurtmccaslin]

I bought one of these, but have not installed it yet.   You should be able to install without getting too dirty!   :unsure:
 
http://www.amazon.com/gp/product/B00A9GDIQ8/ref=oh_details_o06_s00_i00?ie=UTF8&psc=1