I've used nipples from day one, have never had a problem but it's only been 3 1/2 months. I was planning on installing some cups as well, to see what the chickens preferred but never got around to it. I presently have a five gallon water cooler as a supply, cooling it with frozen bottles of water, water level is checked once or twice a day. I use acv and currently wash the cooler, flush the lines & change the water once a week. Should I be changing the water more often?