Okay, now I'm ready to just close the darn pool for the season. I don't know what else to do, and I'm getting frustrated. (Can you tell?)
I didn't get my screenname by accident....if you close now, you'll have the same problem, if not worse, come spring.
Anyway, we don't have the test kit yet,
Does this mean one is on order? If not, at the very least, go to Wal-mart and look for the HTH 6-way test kit. It accurately tests PH/TA and has an OTO chlorine test. IT has enough reagent for 2-3 CYA tests. We need you to confirm, accurately, what your CYA level is. If it's over 70 you need to drain and replace some of your water, or you will very simply, fight a losing battle.
and in the meantime I figured I would just run to the pool store and see what they said I had for a chlorine level. The free chlorine is .1 ppm. So just to make sure I didn't start growing algae, we decided to shock the pool, figured it couldn't hurt, and just might help. We poured 5 gallons of liquid chlorine into the pool last night, let the filter run for 6 hours, and I just tested the water this morning. Even though they are test strips, and may not be the most accurate, we used them for years and I know they would at least register some chlorine if it was there. Well the free chlorine reading is showing nothing, although the total chlorine pad shows an almost normal range for the first time in weeks.
Free Chlorine is what you want. Total Chlorine being higher, means you have CC, which is what you don't want. CCs over .5 means you need to keep shocking the pool, running the filter 24/7. However, you aren't actually "shocking" the pool, you are teasing it....
Was the 5 gallons 12.5%? 5 gallons of 12.5% in your pool, would only raise the FC to about 20. If your CYA really is 125, then your actual shock level is about 47. (http://www.troublefreepool.com/chlorine-cya-chart-t2346.html)
This means you need twice as much chlorine as you think you did.
Here's a scenario to picture. You add 10 gallons of 12.5%. You wait an hour, retest, FC is back down to 5. You go to the pool calculator, enter in a FC of 5 and a shock level of 47, hit calculate, it tells you how many more gallons you'll need to reach 47 again. You'll repeat this process hourly at first, until the FC starts to hold for longer and longer periods, perhaps reaching a point where you only need to add chlorine morning and night. But at first, when shocking, you need to test hourly, and add bleach hourly.
So you can see, the process of shocking, is not dumping in "x" gallons, walking away and testing the next day. This won't accomplish anything. You can also see, that if your CYA is really that high, you'll be going thru ridiculous amounts of chlorine to try and defeat the beast. You need to lower the CYA level if it's really 125.
I really don't know what to think or do at this point, and although my kids love the pool, we have already invested so much in electricity, time, and money for chemicals this season. It is getting ridiculous at this point. Can anyone hazard a guess as to why this is happening, even not knowing for sure because I don't have my test kit? Even guesses would be greatly appreciated!
It's happening because (if the reading is accurate) your CYA level got too high, the FC is no longer effective, you have "nascent" algae that is consuming the chlorine as you add it, so when you test, it shows up as low or zero.
Thanks!
As far as how the water looks, it is crystal clear and looks and feels beautiful. (which only makes everything even more confusing)
If you stopped chlorinating, the pool would turn green within 1-2 days.
Here is the latest from analysis from the pool store (this is from yesterday, before we shocked it)
Free chlorine: .1 ppm Range: 1.0-3.0
Total Chlorine: .1ppm Range: 1.0-3.0
Combined Chlorine: .1 ppm Range .1-10.0
pH: 7.7 Range: 7.2-7.9
Hardness: 200 Range: 200-400
Alkalinity: 100 Range: 100-150
Cyanuric Acid: 125 Range: 30-150
Ignore their "ranges" they are outdated standard industry jargon that is not helpful, the 1-3 ppm FC is based on indoor pools with no CYA. CYA level dictates appropriate FC level.
Pool store testing will not help you. You can't rely on it, unforunately it's just not accurate and sometimes it's outright misleading.
Pool stats:
Inground: 33,000 gal. vinyl liner
Cartridge filer, Pentair chlorinator