If Stabilizer (CYA) is TRULY 50 you absolutely do NOT want to add anything more. I usually say use 1/4 to 1/2 of what is recommended because you can always add more.
You must be using strips because your FC (Free Chlorine) reads higher than your TC (Total Chlorine). This is only possible because the TC pad on strips is worthless. By definition, Total Chlorine cannot be lower than Free Chlorine--because it's defined as the sum of Free Chlorine plus Combined Chloramines (CC) IOW, TC = FC + CC. From years of seeing this I can tell you that the FC pad on the strip is pretty good, but the TC is ALWAYS wrong.

Once you get a proper drop test you'll be able to confirm that CYA reading of 50. Plan on keeping your FC between 3 and 6 for now. Your CYA may go higher--it takes 48 hours to a week to fully dissolve. But we can make sure it's not a problem. In fact, living in Alabama, your conditions may be similar to aylad's and SHE runs a high-stabilizer pool without any problem at all, and does it deliberately. Why? By maintaining PROPER FC levels with a high-stabilizer pool, aylad is able to keep her pool sanitary and clean with a lot less additions of bleach.

Your Total Alkalinity (T/A) is a bit high, but, unless you find you can't maintain your pH, it's not a problem. Looks like you have hard water too, but a CH(hardness) of 250 with a T/A of 180 in a vinyl pool should not give you any trouble at all. So you don't have to "fix" it, you just have to watch it.

In other words, you are doing pretty darn good for a first-timer and your water is definitely swimable. Perfect? What's perfect? Safe and sanitary? Definitely!

Now even though funds are limited you should stretch your budget to get the Taylor K-2006 test kit. I know it looks intimidating but it will pay for itself this season alone in both chlorine and heartache. If you don't get algae because you've known your chlorine levels, you've just save a fortune on the cleanup you did NOT have to make!

Click on the link in aylad's signature and the PoolForum will get a small part of the cost to help pay for this place. However, equally good is the Leslies Chlorine FAS-DPD Service Test Kit. They have a lot of kits, but the FAS-DPD one is by far the best and not the most expensive. The FAS-DPD Chlorine test is the best, most accurate, and widest range test available for the homeowner, measuring chlorine levels from .2ppm to 50ppm! Plus it measures CC to the same range.

Remember: Pool maintenance is easy and no mystery. You worry mainly about chlorine levels and pH levels, and, you aim for chlorine levels determined by your CYA level.

Carl