My pH is consistently too low...

[Wntrequinx]

So I have a brand new AG pool this season and I have had a heck of a time keeping my pH above 7.2. It was filled with tap water, so 7.0 nothing in it to start.
I like the pool best with a pH at the higher end (~7.8), but I cannot keep it there.

I had to add Borax a few times because it was so low I couldn't tell what the pH actually was. And because it started with a 0 TA.

I keep the pool covered a lot and I think that has been trapping the CO2 more than I want, but other than that and stopping using pucks (I still haven't quite gotten the CYA to a solid 30, I'm guessing it's closer to 20/25, but the scale doesn't go that low) I don't know how to help it. I added baking soda instead of Borax the first time because the TA was 0 and I forgot how little it raises pH, so I'm wondering if my ideal TA is actually like 30 or something super low...

As to the pucks - I added all the CYA I had leftover (like 1lb) from my pool store visit with my last pool and wanted to use the bucket of Giant Tabs to raise the CYA (I've used like 10 of them but they barely raise the CYA) (I use one puck in the floater and maintain the the FC with liquid chlorine, because the pH kept diving and I had been thinking it was the pucks).

The trouble is I like my pool warm... 85+, so I have been keeping it covered a lot, and can't run the jets up for aeration when the cover is on.

Anyway, I feel like I'm missing something obvious... any ideas?

Also, dont mind the recent super high FC... I had neglected it last week when my son was away and finally got new chlorine and didn't realize when I tried to shock it how much stronger the new stuff was... (good news, it nuked the algae friday/sat so cleaning it up was easy on sunday)

 

[ajw22]

Stop using Trichlor tablets. They contain acid which drives down your pH and TA.

Use liquid chlorine or get a SWG to chlorinate your pool.

What is the pH and TA of your fill water?

Your PoolMath logs show pH of 7.1-7.2, TA 100 and CYA of 30. That is all fine. Any pH in the 7's is fine.

 

[Wntrequinx]

Ok, I thought it was the trichlor, but wasn't sure if anything else was adding to it. I'm trying to use them up and since the pool had 0 CYA to start, the only downside seems to be the pH issue.

I have 30 listed as my CYA way before it was 30 (once it started showing up I was putting it at 30, because I didn't want it telling me FC super low but it was closer to 15/20 most of that time - it only just reached a solid 30). I was entering my estimated CYA of 15 and 20 in the pool math app to figure out what I wanted the FC targets to be, but it wasn't really all the way up to 30.

Next year I'll have to buy the right amount of real CYA for it, but this year I didnt have the budget if I could squeak by with the leftover from last year and stabilizer in the pucks. Adding the pucks slowly along with liquid chlorine meant it never got too low, but I was always aerating.

I did have one time it dropped below pH 7 (the test kit only goes down to 7), and added borax to bring it back up... but I'm trying to not let my TA get too high.

Thanks!

Edit: the fill water pH is tap water that's usually 7.0.