How hard are they to install? We haven't opened the pool for the season so the water level is already below the return. The pool store quoted $299 for light and install. I am super nervous when it comes to anything liner related. We had a pool wall issue last year, had to replace the liner and added foam to the wall. We should have added foam to the bottom. but too late for that now. If it just fits over the return that is there now, I might can handle that.