I am no expert....and it is a little different on every lake. However, from my experience turnover results in a brief period of very dirty water followed by extreme clarity. However, this "extreme" clarity is dependent on the body of water..."really clear" for Shelbyville is probably 4-6 foot visibility as far as my experience out there tells me. It seems to be one of the less clear of the reservoirs in Illinois. Since there are not any weeds in Shelbyville (at least I have never fished any in Lithia), turnover is harder to tell. After turnover the weeds die off and this is a tell tale sign. Good luck, I think we are about to get turnover here at Kinkaid and it sucks!