This is where keeping a good journal for your pool will come in handy.
What I did in the beginning was test FC and pH every morning and evening. I put that in my pool's journal as well as the weather for the day. That helped me learn what I needed to do each day depending on the weather and bather load.
What your pool is telling you is that it is using more FC than you thought it would. I would push your FC up towards the top of the FC/CYA ratio for your CYA. Look down at my siggy below to find the chart.
-Make sure all big piece of *stuff* is out of the pool.
-Make sure equipment works
-Drain water if needed
-Run pump for about an hour then test water
-Balance pool water as needed from the tests above.
Here is a link to a post a great member made. Look for post #18. It has what you can do get ready for a big storm. Pool Renovation
Well we don't WANT you to need to do a SLAM. The SLAM is only if your water get algae. You can bring the FC up to SLAM level if you get a dead animal in it, a child has a potty accident in the pool, if you get a lot of stuff in your water from a big storm, etc.
As far as doing the cc test it would be a good idea to learn how to do it as it can show you if there is anything hiding in your water. It is easy. Just remember the water will turn back to pink if you let it sit after doing the FC or the CC test. Don't worry about it. Once you get the test water to clear call it good.
It look like my cya is now 0. Can the rain lower the cya from 20 to 0 with 2 days of big rains? I just bought this new hth pod Stabilizier. According them to use 1 pod at a time. Can I use more then 1 to raise my cya faster? According to pool math I need 3 lbs, 4 oz
You can put them in a sock and hang them in front of the return to get them in faster. I would only add enough to get the CYA up to 30 for right now. You may have some but it is so low it will not show on the test. Better to add to little as it is easy to add more if needed.