Constant stream method, I feel it works well once dialed in. Does not require a pricey feed pump and has less chance of the line being effluent line getting clogged. It might be harder on the regulator, but I feel it's worth it.
Why would you not want to glue it? PVC is relatively cheap and, if you dont glue it together you run the risk of it popping at the worst time possible.
I'd say it looks like new growth. Have you recently moved it or, turned it? Does it look like it has little peaks forming? I'm going to call in watchguy123 for his opinion.