the yellow leaves could be root lock or temp problems , but if your having ph level problems then that is probably it, it is not absorbing nutes as they should. I just saw this now, so if you can give us a update. do you have a ph tester the little drops and such? caseu you cant uses those to test drain age, those are only for clear water no nutes and pot drainage. but tap water should work as long as you get the ph down caseu our taps are heavily chlorinated. That is another thing leave your 5 gallon jug uncovered for a good 24 hours then use it in your room, the chlorine is allot for cannabis, buy letting it sit you are letting the chlorine evaporate. for germinating our water should be ok but I always tell people to use distilled and same for clones. this water also has to be ph ballanced of coars.