Bio in the streams is not needed, but strategically placed stones will give you some great aeration along the way from pool to pool with all that splashing going on
. A question I don't think you ever answered (on the other forum). Did you ever test the ph and hardness of your lake water? That kind of info can be very valuable when making your preferred fish selections as some types perform much better with lower ph/gh while others may benefit if it is a bit higher. In closed systems we can at least attempt to manupulate those numbers to our advantage but in your situation you will be at the mercy of nature at work in the lake. Is the gravel more limestone type or high iron content?