Airconditioner in window, had to buy a heater

Well I finally had to dig the air conditioner outa the corner it was stored in and stick it in the window. (**** hot weather) When I did the water temp dropped in the tank and I had to buy a heater to keep the tank regulated.
What is the correct tempature for my tank with 6 convicts and 4 red eyed tetras ??

The tank is a 40g with a 200watt heater in the center of the back wall above a bubble curtian, below the output of the Jebo Newport canister filter. I currantly have the temp set at 74 degrees.

Ok, that sounds doable. On scorching hot days sometimes it is all that the air can do to keep it at 80 degrees. I'll slowly bring the water temp up a few degrees.

Thanks

Update. I brought the temp up to 77 degrees, now my female convict has eggs and is guarding them. What have I done now??