I've been reading through this thread and it seems like just about everyone is hooking up the pump so that the cleaning solution runs in the same direction as the beer. This leads to potential problems with making sure you have the right threaded fitting to attach a ball lock post so that you can connect the liquid ball lock QD to the cleaning line.
My questions is: why not run the cleaning solution in the opposite direction? Then all you have to do is fit the tubing coming out the pump over the faucet. That way, you don't have to worry about getting the right threaded fitting.
If you have MFL connections, you can just unscrew the line from the liquid ball lock post and let it dump the cleaning solution back into the reservoir.
If you don't have MFL connections, you can use one of these:
https://www.brewhardware.com/product_p/ball_lock_jumperpost.htm
It is a fitting that can accept a ball lock on each end and it depresses the poppet so that liquid can flow freely. You just put this in the liquid ball lock QD and that will let the cleaning solution flow back into the reservoir.
Or better yet, you could hook up 2 ball lock QDs to it and clean 2 beer lines at once without the need of a T fitting.
I was originally trying to figure out what fittings I would need to run the solution in the same direction as the beer and they started adding up. If you run the solution into the tap first, all you have to do is fit the tube over the faucet. Seems easier to me. Just a thought.