Besides the hydroguard, do you take any other precautions? Most literature seems to make me believe that hydroguard isn't enough by itself with high temps. My decision is going to be DWC with no chiller or full organic grow with Mephisto super soil. Up until I looked at your grow, I thought I really needed the chiller. I think DWC would be soooo much easier for me. Much easier to methodically record all of the variables and make quick decisions.
No I do absolutely nothing else for bucket temps besides using a beneficial bacteria i.e. Hydroguard. I don't screw around with ice cubes or frozen water bottles. Now I am curious if a chiller would help me even more but as of now I am chillerless.