The floodgates have opened again. Outside spending — much of it in the form of TV ad buys — is now flowing into Hawaii’s U.S. Senate showdown at full speed.

It took a while. Until last week, not a cent of post-primary super PAC money had shown up in broadcast stations’ public files.

The U.S. Chamber of Commerce this week spent at least $170,500 on ads endorsing Republican U.S. Senate candidate Linda Lingle. The buys could have totaled as much as $250,000, according to data from the Sunlight Foundation Reporting Group.

That’s on top of the roughly $730,000 that the Chamber spent on pro-Lingle spots before the primary.

The new spots were purchased on several stations, including KHON, KGMB and KHNL. They are scheduled to air starting Sept. 21.

Mazie Hirono’s folks noticed the buys right away.

“It’s clear that national Republicans and their friends at the U.S. Chamber recognize that Lingle’s campaign is floundering,” wrote Hirono campaign spokesman Kinsey Kiriakos. ”In fact, despite relentlessly attacking Mazie Hirono since day one of the general election, GOP strategists have noted that Linda Lingle ‘just hasn’t panned out.’ Whether the Chamber doubles down on their previous $750,000 investment to rebrand Lingle as a bipartisan leader, or they change course and revert to their typical mainland tactics and go with misleading attack ads about Mazie remains to be seen.”

The Chamber’s spending comes on the heels of the roughly $64,000 that Working Families for Hawaii spent on ads endorsing Hirono.

Another group, Workers for a Better Hawaii, also spent about $16,000 on pro-Hirono ads.

And, just for the record, EMILY’s List’s Women Vote! has spent $75,000 on ads attacking Lingle, according to the Sunlight Foundation.

— Alia Wong