Bio bizz question

Hi! I think pH pen is very important tool! It is not needed necessarily if you really know what you are doing but with pH pen you can always check if everything is going like it should be. If you don't have it and you face some kind of problem there is no way to see if it is pH related and it might give you really bad headache in the long run and worst case scenario it might be the reason your plants die... About the chlorine, here is something I found on the net: Plants need some chloride, which is a micronutrient, to grow, but too much of it — what’s called “chlorine toxicity” — can build up in a plant and result in browning, yellowing, or scorched-looking leaves. It can even cause leaves to fall off the plant entirely, which, in the case of a budding cannabis, of course, sort of destroys the point of growing it at all