Koi pond skimmer filters have a way of getting heavy and causing the filter basket to sag, they don’t bounce back. You can buy a replacement basket, if you can find one. Chances are, the new one will also sag the same way once the filter is filled to capacity with pond waste.
There is another fix and you can save a bunch of cash. When making window screens, save the cut offs from the aluminum used for framing for the screens. This is one of the many uses you will find for the left over material.
As you will notice in the image shown, the aluminum framing makes a great brace to support the back of the basket.
Use the filter (after cleaning) as a template for the size and shape of the back support brace. Trace it on paper or cardboard.
At the bottom of drawing, measure and cut the rail to length. Repeat this step for top rail.
Using your tape measure, determine the center point of the upper and bottom rail and mark the centers.
Measure the bottom rail. Take the length of the bottom rail and divide it by 4. Mark all 4 divisions on the bottom rail. 1 on each end and 1 measured from the right end and 1 measured from the left end of the rail. Place the top rail adjacent to the bottom rail with the center marks near each other. Mark the 2 inboard marks from the bottom rail onto the top rail. This is where the interior support bars will be located from the bottom rail to the top rail.
Lay the top and bottom rails in their respective positions on the layout drawing (Place the top rail ¼” from the top of drawing making the vertical bars a ¼” shorter to allow space for final installation). Measure the distance from top to bottom using the inboard marks as a guide (This will be the length of the 2 inboard support bars.). Measure the distance from the left end of the bottom rail to the left end of the top rail. This is the length of the left outside rail. Repeat this procedure for the right outside rail. If all the previous steps were done correctly both end rails should be equal.
Assemble all these pieces and you should have a good brace for the back of your filter basket. It goes on the inside of the basket against the back of the basket, the filter is installed.
You can use short pointed screws, short machine screws with nuts or pop-rivets’ for assembly.