First off keep in mind pool store testing is primarily used by the pool store as a tool to sell you chemicals, it is not there to make your pool water perfect, so most pool stores don't really care if they get the test results right. Afterall what is the worst that can happen if they get it a bit wrong, they get to sell you something next week to make up for it. This is not to say that pool store testing is always wrong, but the situation is bad enough to many of us here are very reluctant to give advice based on pool store numbers. If you want to observe this yourself take a water sample, split it into 3 parts and take each to a different pool store for free testing and compare the results, for bonus points repeat weekly for 3 weeks and see that not only do they differ from each other, but are inconsistent even with themselves. You can see this by tracking over time certain levels like CYA and CH which only go up without water replacement. as they bobble back in forth all over the map.
The solution to this problem is to buy a quality test kit, I suggest the TF-100 see link in my signature, and do the water testing yourself, and with just a little practice you can achieve far more accurate results than the pool stores. You may ask why yours will be more accurate, the simple answer is because you care and take the time to do it right. For example when counting out drops waiting for a color change to happen like on the CH test, you can take your time and count 1 drop at a time, instead of trying to squeeze out 10 drops per second and keeping up with when you hit the right number. Or on the CYA test which requires correct lighting for optimal results, you can go outside when the sun is out to get the best results.
With your own quality test kit you can get reliable numbers, with reliable numbers it is easy to get the water balanced with just a basic understanding of water chemistry which we can help you with.
Now I will try to answer your questions assuming the pool store tests are right, I would suspect your pool is looking very cloudy, perhaps turning a bit green by this point since the FC is way too low for the reported CYA level. A CYA level that is roughly 3 times higher than our suggested range, if you will note my comment above CYA can only be effectively lowered with water replacement, this means you need to drain 2/3 of your pool water and refill as the first step. Given you have a vinyl liner pool they would likely need to be done in multiple partial drain refill cycles as you should always leave at least a foot of water over the floor of a vinyl pool the keep the liner from lifting.
Now should you do this, who knows, is your CYA really around 150, or is it 250, or for that matter 50?
You could take a water sample to other pool stores and get other answers, but which one is right?
Or you could order one of the suggested test kits, test for yourself, and retest until you are confident in your results and then know what needs to be done.
Ike
ps someone just started yet another pool store test comparison thread yesterday
Commercial Test Comparisons