having possible mustard algae problem 3 weeks now

[PoolDoc]

You may want to test your phosphate level.

I've never been able to discover why, but some pools are prone to recurrent chlorine-resistant mustard algae. For years, I've serviced a large country club pool like this. Even though I treated it like all the other pools, it would develop mustard algae in late summer, and they would not. This past season, I tried using phosphate removers, and it made a huge difference. I can't guarantee the same for you but at this point it's worth a try.

Keep in mind that low phosphate levels SLOW algae growth, and make it more susceptible to chlorine, but do NOT kill it. So using phosphate removers is a 'in-addition' to chlorine, rather than 'in-place' of chlorine!

Phosphate removers vary greatly in quality. The KemTek Phosphate remover appears to offer the most 'bang for the buck', with 1 quart @ $18 removing 2,000 ppb (2 ppm) from 10,000 gallons of water.

Clorox Phosphate Remover @ Amazon

The Orenda product PR-10000 is more concentrated and usually cheaper, but more likely to cloud your pool. It's not available through Amazon.

After testing numerous phosphate kits and strips, only the AquaChek and Taylor tests seem to be accurate enough to be useful, and the AquaChek is only helpful once you've greatly reduced the phosphate levels. Both kits are a bit of a pain to use.

Hach (AquaChek) Company 562227 Phosphate Test Kit @ Amazon

If you want to pursue this, I'd recommend getting the Taylor kit and a couple of quarts of remover. Have her add one quart as soon as it arrives. When you get back, test the water and add more, if needed.