I have a Hayward Pro Series 180t Sand Filter.  I purchased a replacement multiport valve from you (Hayward OEM 1.5" Top Mount Valve) and it fits the tank correctly but the connection to the Lateral stack is very loose (probably .25in short).  It was snug on the old one.  I went ahead and put it together and it seems like it is spitting dirt right back into the return.  Can it be loose?  Does the replacement have different specs?  Is there some kind of hack I can do to fit it together safely?