Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to lower salt levels in a pool [title] Look at your pool's control panel for a quick salt level readout. [step] Most modern saltwater pools come with high-tech control panels that, among other things, allow you to check the water's overall salt levels. Control panels give this number in parts per million, or ppm, meaning you won't need to convert it.

Ending1: [substeps] Though convenient, control panels do not always function properly, making them more prone to inaccurate readouts. [title] Dip a test strip in your pool water for a more accurate salt level readout. Ending2: [substeps] At any time of day, check to see if the power outlet ports are open or to see if it fills up completely. Replace large ports with smaller ones if necessary. Ending3: Some systems produce a rate of ppm that can be changed to 75 ppm, while others only give you the same data. You can consult your net when you need it. Ending4: [title] Look for a submersible (r-1). [step] You want water to be less likely to come into contact with a submersible when you enter your pool or any other underwater place.

Answer format: ending1/ending2/ending3/ending4