OK I do have a few thoughts. The cool side temps are good at 75-80. You want the basking area to be 100-110 with some 90s around it. You want to measure this with an accurate thermometer so I suggest a digital thermometer with a probe or an IR temp gun so you can get accurate surface readings all over the tank. A bright white basking bulb like the ZooMed Repti Basking Spot Lamp should be able to take care of this. You may want to use an adjustable lamp stand to raise/lower the lamp to get the temps correct. A higher wattage at higher elevation over the basking area is usually easier than using lower wattage at closer range.
At night, if the temps stay above about 65 in the tank, no additional heat is needed. If temps go below that I suggest using a low wattage ceramic heat emitter or a heat projection bulb like this
http://www.reptileuv.com/shop/index.php?main_page=product_info&products_id=196 They produce heat but no visible light which can disturb sleep.
UVB exposure is incredibly important. The coil UVB bulbs produce a narrow, intense beam of UVB which is difficult to bask under and may be causing your problems. I suggest moving to a tube style
UVB light immediately. For now, try to find an 18'' T8 fixture (Zilla Slimline works well) and a ReptiSun 10.0 T8 tube for it. Make sure the plastic covering is removed so there is nothing between the bulb and basking area. If you have a smaller 20g tank just put the fixture on top. If you have a larger tank then mount the fixture inside the tank about 6'' directly above the basking area. You can put some small command hooks on the wall and hook them into the holes on the back of the fixture so it will hang from the wall and aim straight down over the basking spot. This will provide a nice wide beam of UVB. If you have a 40g breeder tank (36x18x18'') or larger then I suggest using a T5 bulb and fixture which are more intense. I can provide details on those if needed.
For diet, are you dusting the crickets with calcium powder?