Yay on finally getting the CYA to 70 - good job!
pH is rising quicker cause your TA is at 90. Lowering it to 60 in the normal course of adjusting pH will slow the pH rise a bit. If you want to lower it quicker - Pool School - Lower Total Alkalinity
I'd recommend you do NOT make large adjustments to the SWG - with your schedule and propensity for not testing and dosing often enough, your FC may fall too low. Only adjust in 5% (maybe max 10%) increments. And then only adjust after letting it be for 4-5 days to see how it does. Having the FC a little high isn't going to hurt anything or anybody. FC between minimum and SLAM level for your CYA is perfectly okay to swim in. You don't want to have to SLAM again - certainly not in this heat.
Since you admittedly haven't been keeping up on testing pH and adding acid, you may wish to pop the SWG out and have a look inside. Do NOT clean with MA if it isn't scaled up a lot.
As for the sewer line location - it will be different for even the same exact model house because the connection to the city line at the street is different for each and every lot. Look for any wall cleanouts in the front of the house - that may give you an idea of where to start looking. Do NOT use wall cleanouts for backwashing or draining the pool. There may be issues with the water backing up into the house. The cleanout in the front yard usually connects to a line that is several feet underground - this cleanout is a vertical pipe with a sweep (usually) tied into the main house sewer line. I have 2 in my front yard (had to raise one a few inches to be above the landscape rock) and can pump quite a bit of water down it without issue.
thx. I didn't measure TA today as I know it's gotta still be high. I did add acid, though, since pH already shot up to 7.8 (I think. It was getting dark and it's hard for me to get a great reading at dark). FC was 9.5 at 5:15pm so pump had been off an hour and 15 min (I made sure to put pump on low to measure).
As far as CH in the cell, I checked it a couple of weeks ago and it was perfectly clean. I have been doing well overall this whole time as far as not letting pH rise above 7.8 accept these 2 times I believe, so I"m assuming it's pretty clean.
Thx for the warning not to backwash down house drain. The city even warns against this. Good to know that the clean out won't be in the same spot at each house. What a hassle.
I've been trying to write this and falling asleep over and over. I'll reread tomorrow and post.thx!