4x4 grow tent heat issues

if the fan blows something wiht a smaller opening, the air coming out the other side will be slightly colder. but, a clip on fan may not do much. if you have an old exhaust, maybe hook up some aparatus with some 2Ls and the air pumping out other side with more pressure will be cooler. pressuve, volume, temperature.. ideal gas law. change one and you can impact the others.

Also the ice water can help but it will raise humidity! Even just putting in dry ice is much more beneficial with the added co2 and no added moisture.

I had this same issue. The only way I could counter this was buying a cheap evaporative cooler thanks to some advice from another gd grower. It's great you full it with water and set it to cool, blasts within minutes air at around 18c. It cost around £75 and really helped me out in the summer 👍🌱