I bought a tank from craigslist and it came with this skimmer, I cant identify the brand. Also it doesnt have a control valve, just a plastic tube and the people who connected it left it under water and the skimmer remained powered on like this for a day without working and making a lot of splashing noises... Did this break it? Is it the type of skimmer thats not adjustable? It seems to be working now as I removed the tube out of the water.