Maxi-Jet Protein Skimmer?

[reefguru21]

I recently got a maxi-jet PS for a 20 long without realizing it was an internal PS it will not fit in a tank that short =(

I put it on my 75gallon display tank, there is a SeaClone100 PS already on the 75 but I thought what the heck. I went in to check on it an hour later, and it was doing a nice job, but the cap on the collection cup doesn't fit, and foam was falling back into the tank. What the heck can I use to fix this thing?

[Sahin]

If the cap doesnt fit, it means its broken or something, take it back for a refund or attempt fixing. No point having that skimmer running if all the skimate just floats back into the tank.