Hi Neighbor!
A few suggestions, several, in fact.
When I began with this new house with a pool a few years back, I started a Pool Book. It has all sorts of things that I learned from the pool inspector (flow paths, pressure to clean the filter, how to open skimmer and so on), from the TFP forum, notes on equipment specs, as well as phone numbers and hours of the local pool stores. Eventually I added costs of things I buy regularly. Funny how long it took me to notice that 10% pool shock from Warehouse Pool Supply was cheaper than 3 bottle boxes of Clorox from Sam's, per use. I was a bit smarter on the cost per use of calcium increaser vs. cal-hypo which increases calcium while adding chlorine. All those math things are in my little book.
I also have a file of the history of pool water testing. I made a spreadsheet that covers the data on the cover of the TF-100, and adds space for what I added and what I expected from that. That is; 2 cups of Muriatic Acid, target pH 7.6. Or 1 jug of 6%, target FC 7. Also notes like added 1" water, heavy rain and debris in pool, etc. This record will help you learn the pool faster.
Another thing I suggest, do a test of your tap water; test TA and CH and pH out of the tap. Then let it sit for 24 hours and retest pH. Don't bother with FC or CYA. Unless you may have chloramines instead of chlorine, you would want to know that in rare cases. If you can get a water test from the MUD district online, they may show that. If not you can test for CC and I think it will show up there.
There are times when you want to be aware of the difference between tap water and rain water in your pool. A normal wet winter here will drive CH and TA lower, maybe very low. It is easy to ignore the pool in the winter but you have to know what the rain may be doing to the chemical balance.
I noted that when you retested after refilling the pool by 2/3, the TA and CH were the same. That is a bit odd to me unless the tap water is at those same levels. Could be, not likely though. Often when you refill a lot of water you will have to rebalance and that is a cost to consider for me where tap water CH is only 20 ppm. And my tap water TA is at 220 ppm so a full refill creates a real need for more acid to control pH.
As for taking care of the pool.... you can do this. Save the cost of the pool service. And all the excess chemicals and water replacement that their sort of chemical management will create for you.
