"I bought the 4" airstone for my 10 gallon tank. It is good, but I think It is too strong for my tank. I'm going to get a smaller airstone next time. It really doesn't release that much bubbles, though, thats a good thing because my tank is a 10 gallon tank and the current is too strong, so it's a good thing. Can I use the pump without an airstone? THANKS"