H.O.T skimmer for 20G tank

[ocellaris06]

I am planning to buy a H.O.T protein skimmer for my 20G tank which is still under cycling. I know I should buy one 40G or more. Any suggestions. I read about Aquac Nano Remora. It is very compact. But what is the different when using Maxi-Jet 900 pump or 1200 pump? What is the function of the pre-skimmer for this product? Any parts need to replace regularly. I hate to replace parts regulary like the air stone in some kind of skimmer. Someone let me know that protein skimmer can act as a mechanical filter too.Can these Nano Remora do it and how? Actually, my tank has two turbo snails now (the only livestock). I found that their poop lay on the sand. How can they be removed? Is it practical to use power head to stir them up and then removed by mechanical filter? Does the water return to the tank (from skimmer) like a power head?

[papagimp]

difference in pump size just determines how much is pushing throught he skimmer. They usually don't have parts to replace regularly, just as needed when something does go faulty on ya. Proteien skimming isn't exactly mechanical filtering unless the unit has a separate chamber for that. Like a HOB power filter with built in skimmer or BakPak type skimmer. The poop on the sand will dissolve and the skimmer will pull this out. You should have enough flow to keep things in suspension, but you don't want to kick up alot of sand in the process. And finally, water going to the skimmmer will return to the tank, one way or another, it doesn't all go in and turn to skimmate.