You have about one option for lowering your CYA, replace a significant portion of your water.
CYA can be removed by reverse osmosis filtration but that is really only an option in select few areas of the sun belt and an expensive option when it is available. Pool store voodoo chemicals promising to lower CYA have not proven to actually work.
You can maintain your pool with high CYA, but it will be tough. If your pool turns it will be difficult to even impossible to maintain the FC level you need to clear it.
Your FC level must be maintained at a much higher level to offset the high CYA. You will need a quality test kit to accurately test the high levels you will need to maintain, as you can find your level by
looking at this chart. Assuming your cya reading is accurate, you need to aim for 12 ppm FC and never let it get below 7. If you are showing a level of 100 cya, unfortunately it is likely much higher, possibly well off the scale, even double or triple as we often see on this site.
The reason is simple, tablets and dry shock products add CYA with every tablet and every bag. It accumulates and stays in the pool long after the chlorine is consumed and gone.
You must stop using those products immediately and switch to bleach or liquid pool shock. Elevate your FC level and get a recommended test kit on the way.
Most TFP users dose their pools daily with plain household bleach or liquid pool shock. These are the same product, pool shock is slightly more concentrated. You can use the poolmath link at the top of the page to calculate how much you need to add to reach the correct level. Test each day and add the required amount to get back to target level.
A TF100 or K-2600 test kit is imperative, both to get a CYA reading and to test and maintain the high FC level accurately. CYA will reduce over time with dilution from rain, splash out etc. Evaporation does not help to lower cya.