Lower your pH to 6.8, and then aerate. Your TA (Alk) is already fairly low, so aeration is not going to produce rapid reduction.

Please also note that if your spa is not MIXING the water with your pool, aerating the spa will have no effect on pool water. Many pool/spa combos are plumbed to share equipment, but not to actually share water. Some like yours may be combined OR may simply mix on an occasional basis.

If your spa's spillover runs CONTINUOUSLY into the pool, you have shared water. And, the spillover itself should provide all the aeration needed.

Quick sanity check? If you can maintain your spa water at a different temperature than your pool, aerating your spa will likely have LITTLE or NO effect on your pool water.