The tablets have CYA in them that stays in the pool even though the FC is used up ... once the CYA level gets too high, maintaining the pool can become difficult.
If you have a short pool season, and replace a lot of water throughout the year (resulting in low initial CYA levels), you may be able to get by using the tablets. The forum is about testing and understanding what you are putting into your pool and why. If you are diligent about keeping an eye on your levels (specifically CYA), then the tablets can work ... there are many reports on the forums of people successfully using the tablets when they have short swim seasons and a lot of water change due to rain/snow/and filter cleaning.
You have a good test kit on the way and that will help you know what if going on in your pool. Wait until you have a full set of test results and then we can see what may work for you.