I have a cottage with a grey water pit for the shower. The pit is clean, it is about 5 feet by 5 feet by 5 feet deep filled with 2 -3 inch stone and landscaping fabric to stop the leaves and grass but there are roots that get in there and plug off the effluent pipe. I am OK for a year of two but then I have to dig it up and pull out the root ball that has accumulated at the outlet and then everything is fine.

I am thinking of putting a soil sterilant or blue stone down the drain once a month to keep it clean... will it work?

Call around to garden supply stores and ask for fine grain Copper Sulphate. Put a 1/2 pound in your pit and repeat in six months. Good luck, Tom

Copper Sulphate is blue stone for those that don't know.

"blue stone" Copper(II) sulfate - Wikipedia, the free encyclopedia

Not "bluestone" Bluestone - Wikipedia, the free encyclopedia

Thank you for the information. I guess you're never too old to learn. Tom