SAN ANTONIO -

Texas voters will head back to the polls Tuesday to settle some primary races that ended up in a runoff election.

Bexar County Elections Administrator Jacquelyn Callanen said voters casted more than 40,000 votes during one week of early voting that ended last Friday ahead of the runoff.

"For a runoff, we were expecting and hoping that maybe we could get 18,000 total, so that's a wonderful change for us," Callanen said.

One of the races driving voters to the polls is the election to fill outgoing U.S. Sen. Kay Bailey Hutchison's seat. 

Republicans David Dewhurst and Ted Cruz have reportedly spent a whopping $37 million on ads in the primary race.

Dewhurst has been the Lt. Governor since 2003 and he's backed by traditional conservative Republicans.

Cruz served five years as the state's solicitor general and is drawing support from the tea party movement.

In other races, two Democrats are battling each other for a chance to take on Republican Francisco 'Quico' Conseco to represent the 23rd Congressional District.

Ciro Rodriguez served four terms in Congress, but lost his seat to Conseco two years ago.

State Rep. Pete Gallego, who has served in the Texas House of Representatives since 1991, is facing off against Rodriguez.

Another big race is for Texas Senate is in District 25, which pits incumbent Jeff Wentworth against challenger Dr. Donna Campbell.

Wentworth has held the seat since 1992 and is supported by traditional Republicans while Campbell is a tea party favorite.

Finally, the race for Bexar County Sheriff pits Sheriff Amadeo Ortiz against Andy Lopez.

Ortiz has been sheriff since 2009. The winner will face Republican Susan Pamerleau in November.

Polls open at 7 a.m. Tuesday.

For a list of recent stories Tim Gerber has done, click here.