I'll have a play tomorrow and see what's what. I think the slightly cracked valve might work out pretty good on reflection. I think at low speed there is no worry about any aeration driving up pH. I want to start playing with how slow I can run the VS pump too and keep the SWG happy.120kg of salt should increase salt level by about 3300ppm. I'd give it about 2 days to dissolve, then test and top up to get a bit over 4000 I'd say.
CYA 30/40 is fine for now.
I have a similar setup with the spa. I just keep the spa overflow running the whole time, otherwise I'd just forget about it without automation. Only downside is potential higher aeration from the overflow resulting in faster pH rise. In my case the effect doesn't seem to be huge, waterflow over the edge looks quite laminar as long as the pump is not too fast and the water level not too low (higher drop from spa to pool surface), and around pH 7.8-7.9 it is quite stable. You can turn the valve a bit down to reduce the flow and see how you go.
TA definitely had a response to the CYA addition IMO. Any other idea why this may have moved 20ppm (beyond rookie making screw up in his procedures 😂)
Any ideas on being short on the CYA test liquid?