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I have very similar alkalinity to yours. Mine was in excess of 480ppm. Step one is to not get in a huge hurry to get it straightened out. Concentrate on maintaining your chlorine level so the pool water stays safe and clear. Alkalinity is a second tier problem.
What you will find is that your pH will probably climb rapidly. You'll be adding muriatic acid almost daily, so it pays to shop around for the best price. I get it for less than $4 a gallon at Rural King.
You'll want to take a multi-front approach to your TA:
First, you want to minimize the well water you add to your pool, because it has more carbonates in it. That means taking advantage of rain water during the season and over the winter. I backwash whenever there is extra water in the pool from rain. I also have a mesh winter cover so I catch as much rain as I can over the winter. This process reduces the amount of high TA water I add to the pool, and lets me dilute the high TA water in the pool with zero TA rainwater.
Second, you need to stay on top of your pH. Lower it into the 7.0-7.2 range every time you have an opportunity. When you lower the pH to around 7, some of the carbonate in the water is converted to carbon dioxide. Aerating while the pH is low allows that carbon dioxide to escape from the water which removes some of the carbonate and lowers the TA. With such high TA, the acid then aerate process will be tedious and long lasting. Do it when you have time, but concentrate your efforts on maintaining your pH. It will lower TA, because aeration happens from normal water contact with the air, the flow from your returns and splashing that happens when people swim.
Now that my TA is reasonable, I keep my solar cover on as much as possible to reduce evaporation. Evaporation hurts you twice, because the water that leaves doesn't take the carbonates with it, so the TA goes up, and it requires you to add more well water that puts more carbonate into the pool. Unfortunately, the aeration process encourages evaporation, so you'll need to live with it at first.
For aeration, rotating your return(s) to break the surface is usually good enough.
It took me about 3 years to really get my water under control. I don't even test TA routinely anymore. Once you get your pH to be stable, it doesn't matter so much what your TA is. Mine was 140ppm the last time I tested it.
Give us some details about your pool so we can refine our advice to your specific needs.