Getting your water quality up to snuff after a winter shutdown takes quite a bit more than unlocking the gate and throwing the switch. Even more so if you’ve used the “create-a-swamp method” of winterizing, so common in rural community pools.
Were you chlorinating in some way all winter long? If so, getting your “balance back” will be easier. Check the chlorine residual, hoping for a trace of pink in that DPD test vial. If clear water is all you see in the tester, or maybe even turbid water with a bit of suspended solids, you need to do a gross supersuperchlorination by adding, with a shovel, many pounds of calcium hypochlorite or gallons of bleach before you do much of anything else.
For each 10,000 gallons of pool water, you probably should add two gallons of 12 percent bleach or 3 pounds of cal hypo. More is better. Once, I added a couple of 50-gallon containers of bleach to the deep end and mid-section of a 120,0000-gallon, swampy pool — and got strange and wonderful results. The brown water turned green, then slowly cleared. Conditions the next day were suitable for filtering, treating and warming.
You may not have to wait a day to get down to chemical-balance business if the water was better than just described. But there are a number of tests you’ll need to run first to find out.
After you’re sure there’s still a chlorine residual, check pH values, correcting to a low 7.4 with soda ash (up) or muriatic acid (down) to get there. If the pool is automated, set the controls at 7.4. Make sure the chemical-corrector material is available, with pump in place and working properly. (You can change the pH target later; this is a good start.)
Plaster-lined pool? I hope your “balance” has been adequate all winter, but if not, get it there now. Because the pH/temp/TA/CH/TDS balance is critical for the life of your plaster (and for your plumbing and heater in some cases) the Calcium Saturation Index should be neutral or positive, not negative. (Refer to your little circular calculator for a quick check.)
If you’ve been using calcium hypochlorite all along, or your makeup water has high hardness, you’re almost certainly fine. Otherwise, get that calcium hardness (CH) up there again to 300 or 400 parts per million. (More can be good; less NO good.) Use about 11 pounds of this granular stuff for each 10 ppm rise in a 100,000-gallon pool.
The alkalinity is all about bicarb. As your test kit tells you, you may have to add bicarbonate of soda at a rate of 15 pounds of bicarb for each 10 pounds of TA in that 100,000-gallon pool. Get it up to 80 ppm at least — though 40 more won’t hurt. It is simply an index of water’s resistance to pH change, a pretty important variable. Check it now and then, and keep it managed.
The TDS is nothing to fuss over, no matter what your pool-supply dealer tells you. An article on www.ppoa.org called “What’s all this fuss over Total Dissolved Solids” makes it pretty clear that very little varies with high TDS. Please don’t drain your pool. Do you have 2,000 ppm TDS? Never mind. Hey, sea water is 32,000 ppm TDS, and we still can “balance” it and swim in it safely.