To combat the ugly bio-film and the white line on my glass I bought a lily pipe that claimed to stop bio-film forming. It doesn't work as advertise! I started looking into surface skimmers, but they are all bulky and ugly. After some hours of google-fu I came up with the solution.
An add-on that you can barely feel it! And it's adjustable according to your performance need!
1. you'll first need a tube that can be cut. I found the cheapest tube from Linens and things, they have different sizes so order it according to "your size"
2. The idea is to use some of the sucking power from the intake lily pipe, so you need to redirect some of the holes to use water from the surface. I first tried to use an o-ring washer, but it's only available in an ugly orange color and it's not that adjustable in application. So I decided to use this:
1. I cut out many straight lines on one side of the tube, it will be where the water is coming from
2. I cut a hole in the finger cot, put it onto the tube, then I put the tube onto the lily pipe intake. Da Da, now you have a skimmer!
I changed to use finger cot instead of O-ring washer was because the flexibility. It is highly stretchable and will fit both the intake and the tube. Also you can pull it up and down to increase/decrease the suction power.
You can also attach some floating material to the top of the tube, so that it will self-adjust according to the water level. You just have to keep the finger cot longer when you cut it and tube can move up and down freely with the water level.
After running it for an hour now the bio-film is gone!