A Durso is designed to make your tank quieter, it will not be louder.
Water level in your sump will not "mimic" evaporation, it will decrease with evaporation. You will accomplish this by fixing your plumbing, which means you have to replace the slotted pipe with the solid one.
Right now, the situation in your tank is that the overflow wants to be at the level of the lowest slot on your slotted pipe. If you were to just leave it that way, then you will see the water evaporate from your sump, the way it's supposed to work. But you don't want to leave the water level in your overflow that low, because it is too loud. That's why you keep adding water to it. If you stop adding water to your overflow, you will see the water evaporate from your sump.
Right now you need to replace your slotted pipe with a solid one, which will quiet your overflow by raising the water level, and you will stop adding water to the overflow. When you do that, you will see water evaporate from your sump, and your system will be quiet.
Water level in your sump will not "mimic" evaporation, it will decrease with evaporation. You will accomplish this by fixing your plumbing, which means you have to replace the slotted pipe with the solid one.
Right now, the situation in your tank is that the overflow wants to be at the level of the lowest slot on your slotted pipe. If you were to just leave it that way, then you will see the water evaporate from your sump, the way it's supposed to work. But you don't want to leave the water level in your overflow that low, because it is too loud. That's why you keep adding water to it. If you stop adding water to your overflow, you will see the water evaporate from your sump.
Right now you need to replace your slotted pipe with a solid one, which will quiet your overflow by raising the water level, and you will stop adding water to the overflow. When you do that, you will see water evaporate from your sump, and your system will be quiet.