so got one second hand with a tank. needs a clean, easy enough, the temperature gauge seems to work, waiting to test the element (used hot water to fill it and its hotter than 29 degrees ... ooops any way all seems well until.. i noticed there is no... Eheim (7444410) External Filter Floater Spring & Holder what does this even do? parts are relatively cheap, and thinking should i just get a new propeller at the same time? or do i test the filter before investing? connecting it up with some water in a tub? or without the above part will it just leak?