How to fix lewmar low profile hatch leak

In 2018 I changed til gasket around the plexiglass to a new one but it was still leaking due to the frame not was tight enough fitted around the rubbergasket, at first I fixed the problem by adding some painters tape to the edge to make it a bit thicker, the point was to get a tight fit. It worked perfect but water and algaes has now eaten up the tape and the hatch is leaking again. This time I use the world known butyl tape, it is a sticky rubber like product there is restant to UV and water, the butyl is a product there was used a lot on boats back in the 70 and 80ies. Now adays they just use nothing or a small amount of silicone to keep the costs down.