Cracking and stains in surface

[Connectix]

I just bought a house with a pool and have been reading up on the TFP method. Currently in the process of draining and refilling some water to lower exponential CYA levels. My question at this point is about my pool surface. It has tiny spidery cracks throughout which are more pronounced in areas with dark staining (see photos). Any advice on the functional detriment of the cracks, likely source of the staining (metals?) or remedies would be much appreciated. The water itself is very clear but I'm afraid it's a timebomb with well over 100 CYA. Thanks in advance!

 

[Connectix]

I thought I would add that the pool just finished filling and I checked my levels with the TF-100 in case that helps anything.

FC 6
pH 8 (or more?)
CYA 110 (55 when diluted in half with tap water)
TA 170
CH 490

Clearly the CYA is still very high after draining/refilling approximately half of the 25k gallons, but I will try to live with it for now and compensate by raising my FC. I've added 128oz of 10% bleach to bring the FC near 10 at least. I'm planning on adding about as much 14.5% muriatic acid to bring the pH down (will take a lot with such high TA). The high CYA/CH are clearly a concern but I'm not sure I can drain and refill it again right away. Any advice welcome.

Thanks!

 

[Connectix]

I thought I would add that the pool just finished filling and I checked my levels with the TF-100 in case that helps anything.

FC 6
pH 8 (or more?)
CYA 110 (55 when diluted in half with tap water)
TA 170
CH 490

Clearly the CYA is still very high after draining/refilling approximately half of the 25k gallons, but I will try to live with it for now and compensate by raising my FC. I've added 128oz of 10% bleach to bring the FC near 10 at least. I'm planning on adding about as much 14.5% muriatic acid to bring the pH down (will take a lot with such high TA). The high CYA/CH are clearly a concern but I'm not sure I can drain and refill it again right away. Any advice welcome.

Thanks!

Thanks, maybe the pool store will have more input.