I'm wondering if I really need a protein skimmer. I hear a lot of people use them and that they work really well and get all kinds of crap out of the water and stuff. But I only have a 10g tank and all I'm going to have in there is some live rock and a mantis shrimp. About three inches of sand substrate and I have an HOB filter rated for 100 gallons an hour, along with a 100 watt heater. I currently have a damsel fish in there but as soon as I get the shrimp is there, the damsel is just food. So do I really need a skimmer? I can't imagine that one animal could produce enough waste throughout the whole tank to need one. Advice, tips? Thanks