Newbie with MAJOR problem...

[Laguna Joe]

Buy an 8' long piece of angle or channel iron, or all-thread rod. Have someone position and hold the end against the concrete, while a second person uses a small sledge hammer on the end that juts out above the water level to drive the iron rod into the concrete chunk.

Pre-arrange a method to signal the top-side person so you can control or stop the hammering in the event of a problem or the need to reposition the iron rod.

And keep your fingers clear.

[roxy]

How about an electric plumber's snake? These electric augers can be rented from any rental store, and are usually at least 100 feet long. You can have someone above operating the motor as you feed the auger into the drain. I would again reverse the water flow to blow out any debris that may break up. Not very familiar with the construction of the main drain, so this is a shot in the dark! Good luck!
P.S. If you use anything electric be sure to plug it into a GFCI protected outlet and make sure the operator is familiar with the tool....those snake can easily get away from you!!

[waste]

Dog, welcome to the forum You say you have air bubbles in the pump, is there a chance that the pipe itself was breached allowing the concrete in, in the first place? If so, have care removing the obstruction as you might cause a fatal leak in the pipe (using power equipment or excessive force is also not a good idea as the pvc pipe will probably give before the concrete). If the crete was just a glob that ended up in the pipe a good poke should have freed it, I fear the pipe was compromised before the crete was poured/ shot (pvc & crete don't bond very well).
I would suggest keep doing what you have been (I know, pain in the @$%& and all those trips to the dive shop to refill). If you want to get a hammer and 1/2" cold chisel involved, have someone topside hold you down with your wallbrush, but be careful about the pipe. Once you get it down to ~ 1/4" mix up some 2 part epoxy (any plumbing store will have some) and generously coat the entire area, making sure that you have a good layer over the remaining concrete and adjacent pipe. Wish I could offer a better solution, but I believe this will take care of the problem. GOOD LUCK! - Waste

[duraleigh]

Dog,

Listen to "Waste"!

Bangin' on that PVC with power equipment or a sledge is an invitation to a much larger problem.

As an aside, it doesn't seem to me this is the source of a suction side air leak. It's not clear to me how air could be entering the system that far underground

[CarlD]

Dog,

Listen to "Waste"!

Bangin' on that PVC with power equipment or a sledge is an invitation to a much larger problem.

Hey! I was gonna suggest dynamite next! Are you saying that might not be a good idea?

[MyBlueDog]

Thanks.

Question for the engineers/scientists: Wouldn't a main drain suction blockage at 6' underwater, and a pump surface side 2' above cause the pump to pull oxygen from the water.

My thinking is since water contains O2, that any blockage in the main drain would restrict flow, causing the pump to work at the same rate, yet pull O2 from the water at a faster rate than it actually sucks the water.

Make sense?

[JJ in Tx]

How about a air chisel like on this page,used very carefully of course.

[South_Texas_Sun]

How about using an air drill with a masonry bit, putting a bit of electrical (waterproof) tape at a fixed depth on the bit (to avoid drilling through the bottom of the chunk and through the PVC) and drilling a hole for a concrete fastener?

Best case, you drill a pilot hole for a concrete screw (don't know the right name for them, but they have 'em at Lowes, etc) Then you use a wratchet/socket and install the screw. Grab screw with vise-grips and gently tug it out.

Worst case: Drilling and tapping breaks chunk in half and comes out in pieces.

CYA disclaimer: Be sure to unplug the air compressor before starting to drill, just in case the air hose has metal sheathing all the way down to the coupling!