i have this exact one. i just used teflon tape to fix all my leaks. i stripped the threads out of one but lucky i was able to take it off and use my die grinder and take some material off so i can get some good threads again. plastic is nothing i can heli-coil.
they sell all those quick disconnect fittings and a hardware store, i picked up a few extra and some more tubing. if the fitting leaks from where the tubing is inserted, take it out again and use a flashlight to look at the Oring inside and see if its out of place.