I built one just like that. I might lower mine a little bit. Right now the skimmer is sitting in 6" of water. That's around 15.25 cm. The recommended range is at least 15 but not more than 20cm with 17 being ideal. I want to get to that ideal range which is a little over 6.5 inches. So, I need to lower my stand about 1/2".
Also, I'm experimenting with different settings on the white pump dial/inlet thing. I had mine screwed in way too much and since I've un-screwed it to the recommended 2 turns, it works a lot better now.