Dear Peg and all-

I'm FINALLY getting around to installing the LectraSan EC you all helped me with a few months back. It tests perfectly in my garage.

Here's the question- Do I need a vented loop for O2 purposes, if not for anti syphon purposes, with the LectraSan?

The situation is: The toilet out let is about 24" above the water line, and the LectraSan will mount about 8-10" above the waterline, and the discharge seacock is about 4" below the waterline, so I'm not worried about raw water flowing back uphill into my system.

Do I need a vented loop, and if so, where in the system?

Thanks in advance!

Don

If foth the toilet and the L/S are well above the waterline, no vented loops are needed on a houseboat.  

Wouldn't hurt to add a vented loop between the toilet and the Lectra/San, with the top of the vented loop the highest point between the two.  this will help to hold water in the bottom of the toilet bowl between flushes, like at home.  Otherwise, it'll either drain or siphon out betwen flushes, and the bowl will be dry.