Nope! Measure the temp on the glass. Some balls burrow into the substrate and if the glass is too hot they can be burned!!

To the OP: Great job for hanging in there and trying a million things to get it right!! The Herpstat will help immeasurably. You might also try wrapping your tank with foam board or cork or rigid pink insulation to assist with keeping temps where they ought to be by decreasing heat loss through the glass.

Keep up the effort and let us know how things are going