"robgraham" wrote in message
ups.com...
I can back up what Chris says about (a) smell and (b) the inlet being
some 18 to 24 inches down. I've a two chamber brick tank about 5 ft
square but not 20 ft deep, 6 or 8 ft I seem to remember. The inlet is
a vented trap constructed from porcelain pipes. The water passes over
a weir from one tank to the other and then goes out to a local burn via
a field drain - again this outlet can be clearly seen on the side of
the secondary tank.

It is worth noting that the first tank builds up a semi-solid cap where
the 'crap' breakdown action occurs - I'm tempted to think that if your
'tank' doesn't have this, it's not the primary one. And rather than
flush the loo, I would fill the bath with cold water and let that run
out as it may take you some time to hear the water flow. I would also
look for the vent to the trap into the primary tank.

Thank you all for your replies. I had a look at this the weekend and can
report a little more detail. It is large.

There is a second chamber which I couldnt see when I first posted because
the baffle(?) between the two chambers was under the water level ( and it
was dark and I couldnt quite see it!)

The inlet pipe is quite low down the tank side - or whatever it is - and
that was also on the water line at the time I posted.
The following morning when I investigated further it was visable ( water
level having dropped somewhat).

It is a bloody large tank! Much biger than I envisaged but it two chambers
apparently.

I am not sure what a crust is supposed to look like - will I see it or is it
under the water level? Does it circulate on top somehow? I may in facty have
one I am not sure since I am not sure what I am looking at ( that makes me
sound really thick I am sure but frankly septic tan ks and sewers have
never been high on my agenda previously.

I have , I think, now cleared the blocked drain and all the crap sailed into
the chamber through the hole followed b y much water that I flushed down to
clear it away.

I have for the moment put the man hole back and am waiting to see how it
goes.

I am unsure whether I need to get it pumped - maybe I should anyway in case
in neds re starting for decomposing since I have been stamping about (
metaphorically) in there.

My new worry is why my drain blocked. I am not sure b ut I may have a
dropped drain . I rodded down into I thought was about six inches of the
outlet into the tank and hit a block. I rodded back from the tank into the
drain and went back about 18 ins before hitting a block.

Short of escavating I am not sure how to establish if I have any problem....
or was it just a hard blockage and have shifted it?

A mucky septic tank story - at my second child's christening, the 3/4
year olds came up from the bottom of the garde saying there were
jobbies down there - a nappy liner had gone down the loo and blocked
the trap to the septic tank with a corresponding outflow from the vent
- just what you want when grannies, great aunts and all the rest are
there.
Rob

Rob

Rob