Originally Posted by
AnnaK
Few of us ever shock our pools unless we become aware of an incipient or active algae outbreak. We use plain 6% regular household bleach as sanitizing agent, adding an appropriate amount daily after testing for FC, CC, and pH. Water in balance that's properly maintained requires neither "shock" nor algicides. Thank You! I am kind of overwhelmed with reading so much info and was confused on the "Shock"
Now, your test results:
FC = 18.2 – as Janet stated, that will drift down by itself. You want to maintain it between 3 ppm (never lower) and 6 ppm. When you test, you do NOT need to use a 25 ml sample. You can use 10 ml pool water, a heaping dipper of DPD powder, and multiply the drops you've counted by 0.5 to get the ppm.
CYA = 42 – Is the number 42 an actual line on the comparator? No, the comparator only shows 40 and 50 but was close to 40.
Anything between 30 - 50 is okay though we see the best results with CYA nearer to 50 ppm.
TA = 70 – that's okay but a little low. You might get better pH buffering with TA around 100. Get some Arm&Hammer baking soda, a large bag, in the baking aisle of your grocery store. Add 3 cups of baking soda. You can add it to the skimmer while the pump is running or in front of the return. Keep the water circulating so the baking soda mixes in, then test after 3 hours or so. You'll like be in the 80s somewhere. Add 3 more cups. I picked up 2- 2 lb. boxes and added half a box. I will check in the morning and add more.
pH = 7.0 – that's a bit low. It will go up somewhat with the addition of baking soda, so I wouldn't do anything with the pH just now. While you're out buying baking soda also pick up some 20 Mule Team borax in the laundry aisle. We may need that to fine tune the pH later.
As to pH testing, when the FC (chlorine) is over 10 ppm the pH test is not valid. Let's let the FC drift down below 10 ppm and then deal with pH. You do NOT add more drops to get a better/different color. The chemicals are calibrated for five drops and what you see is what you have. The drops I added were part of the "base demand " test that my taylor kit said to use. It took six drops of R-0006 to reach a ph level of 7.6. The PH was around 7 to 7.1 before the pool store "balanced" the pool but, I will wait until FC drops below 10 ppm to check PH again.
While you're out shopping pick up some bleach. Plain, unscented, un-gel'd, just bleach. That will be your daily sanitizer and your "shock" and your algicide.