I'm trying to add a second shower head to a shower stall in the basement. What do I need to do to make sure an equal supply of water at the same temperature runs to both heads. I tried to just run a line from the first shower head to the next but that doesn't work.

I recently bought a dual shower set at Lowe's. One head is fixed and the other is on a stainless steel hose and both can be changed from gentle to a more powerful stream. Also there is a control where you can turn either one off and just use one. The water pressure in both heads is great and the whole thing cost less than $50 (if I remember right)

Would that work?

Sounds like you are trying to supply both heads with one valve. Unless they are identical in every way and at the same height, tee from the same supply line, this will not give you a satisfactory operation. One head will have more pressure than the other. You might consider a second controlling valve for the extra head.

Purchase a small valve to go on the shower arm on both heads and regulate it from there.

Thanks for your responses. I can't add a second mixing valve due to space. I did route the supply line from the mixing valve to a point half the distance between both shower heads which are at the same height on opposite sides of the shower stall from each other, but haven't tried it yet. Hopefully, that will help distribute the water equally to both heads. What kind of valve is it that can be added to the shower arm?