Congratulations on your new skimmer and thank you for your inquiry. I will put your request in our lineup.
1) Skimmers are designed to sit in a certain water level to achieve a particular air to water draw from the pump. If the skimmer is placed in too deep of water their is less distance from the water level within the skimmer to the top of the neck and can cause the skimmer to overflow. Also running in higher water levels effects the amount of air that the pump is capable of drawing in. If the water level is lower, in most cases the user would then close off the output valve too much to obtain a collection and in doing so the added water volume above the sumps water level would place back pressure on the pump hampering its performance. Also the excessive water level height in the skimmer body would leave little to no buffer area if something changes the surface tension of the water which cause and instant overflow. Test have shows that the Regal 200 does best at about 7-8in of water.
2) After the initial break in period of 3-4 weeks you slowly close the output valve so that you retain pea size bubbles where the collection cup attaches to the skimmer body. You want to try to keep this level for about a week as this setting acclimates to your system. After this time you can fin tune the skimmer by opening or closing the valve in small increments every other day till you get your desired collection. Remember not to ever make adjustments after feeding, cleaning or messing with the aquarium.
3) Some users find that speed 3-4 they obtain better results. Not every system or users likes to run a super high air intake skimmer. I myself find that at speed level 4 I achieve a more rich collection of skimmate Vs speed 5. When you cut down the speed you are not only cutting the amount of air being drawn in but your also processing less water. So in essence you are capable of further fine tuning your skimmer to your overall system. I suggest for starters to either stick with power level 4 or 5.
4) Let your skimmer run. Microbubbles will slowly diminish the more it runs, usually becoming non existent after the break in period.
Hope this helps.