I filled my pool with well water that has a sulphur smell and 300 plus alkalinity I have been adding muratic acid about every 4-5 days to bring ph back to 7.2 but alkalinity seems to not be lowering any suggestions?

Can you post a full set of test results?
The sulfur smell will go away but I'd keep the FC on the high side of normal.

Yes I have to get a set FC is on the high side the sulphur smell is gone just wondering if that is why the well water alkalinity is so high

Possibly but there's a lot that goes into making the TA high. Acid will bring it down though. Just keep adjusting the pH down every time it gets up.

I read somewhere to add the acid to the pool with the filter off so it can get a better bite on the compounds making the TA high they said do this for about 30 min then start the filter. What do you think?

Keep the pump running. The "slug" method is a myth and it doesn't work any better than pouring it in front of a running return. It takes the same amount of acid to move the TA and there's much less danger of damaging something.

Thats why I asked thanks.

I have the test results from this morning
Ph. 7.5
FC. 3 ppm
Hardness. 100 ppm
Alkalinity. 240 ppm
CYA. 60 ppm
Alkalinity is below 300 for the first time yeah!

JUst keep after it and it'll keep coming down.

Yes it came down TA is at 160 now and still dropping Thanks.