CPU fan problems!

I have the coolermaster seidon 120 cooling my cpu for my pc. The problem is the motherboard I have ( Asus M5A99FX PRO R2.0) has one 4 pin cpu fan connector and a 3 pin cpu opt connector. The fan and the water block has a 3 pin connector and it is loud due to the fact that it needs to be connected via a 4 pin connector. Could someone help me figure out what I need to do to stop the cooler from running at 100% all the time? Also, I have eufi bios. Thanks!

Install the software it came with it. or go into the EUFI BIOS and tune down the speed on the fans.

What would I need to do in the bios to fix it? I have no idea what needs to be done.