ok then, i just needed some facts on it crm, i didnt know the cheap ones are bad, im new to the hobby remember, i thought a skimmer was a skimmer no matter what. Another question, is there such thing as over-skimming a tank, i found a second hand prizm skimmer but there rated for 100 gallons or more, it was a pretty good price but im worried it will be too much for a 20 gallon.
Also remember i have many restrictions, my mom will never buy stuff online or take materials from shipping, she will only get second hand stuff when she goes there herself and picks it up after seeing it in action. Thats why i cant just get any second hand object that is cheap but not in the chicago area, my mom just wouldnt do it.
How does a skimmer work anyway, i know bubbles come up through this tuby thingy and this cup gets filled with dissolved fish poop, but how? How does only the fish poop go into the cup and not water?