WTB: In sump protein skimmer

[dnizzle]

looking for an in-sump protein skimmer in Edmonton. The sump is only about 10-15 gallons so the skimmer must be able to operate at 5-6 inches of water depth. It is for a 30 gallon tank. I was looking to get a tunze nano or hydor nano slim but i am not even sure if 5-6 inches of water is tall enough for these skimmers.

Please let me know what you have, thanks!