Not with the pump running. If it’s well mixed divide the rainfall (1 inch ?) by your depth in inches and it will be 1%-2% at most, probably much less but even on the high side with an absolute whopper of a storm, 2% would lower your 20 FC to 19.6 and be unnoticeable.
Just got home and pool water is up 2 inches from all the rain. Today was a very hot and humid day and FC just tested at 15.5 and CC at 0.5. Poolmath said to add just under 2 gallons so I added 2 gallons of bleach. I retest in a hour or so.
Just tested this morning and FC still 22.0. I’ll say CC was 0.5 but it could be closer to zero too as after I add the five drops R-0003 the water maybe barely had a pink hue. Water looks clear as ever so if I’m correct I am done with the slam.
per pool calculator I added 24 ounces of 31.45 muriatic acid. Also says to add 61 pounds of calcium chloride. That seems like a lot and I don’t have any so it’s time for a road trip.
just took pic of R2D2 in the deep end. Today is an overcast day but water looks super clear
Water looks great! A CH of 150 is a bit too low for my comfort. I would consider increasing it to at least 250. You might lose some of it in a month or so when you winterize, and the pH will rise in the cold water which helps your CSI, but I still think a little calcium would be a good thing.
Bought a 25 pound bucket of calcium hardness increaser and will add it in small doses over the next few days. For any newbies reading this, I highly recommend following every word of the experts on this site. No shortcuts. I now know the difference between pool store water clarity and TFP water clarity. Our water has never looked so amazing. Thanks to all that helped.