We have been out to lake isle a few times in the last few weeks. We have pulled out several keepers on yellow or red deep divers. We have had the most luck trolling around islands and in about 20 ft of water.
Yes the water quality is terrible. Although i think that probably has to do with the amount of human traffic and waste near the lake. You could do a weed kill although i think that would be a temporary fix, but what do i know, im just a girl