Cant keep chlorine

[PoolDoc]

Your post raises a lot of questions:

1. How are you testing?
I'm not aware of any test kit that will allow you to measure 0.03ppm of chlorine. If you are using a meter, you need to replace it with a cheap Walmart OTO kit for now, and consider getting a better one. (Amazon links below)

2. What was your CYA last fall?

3. Have you added anything at all this year, besides water, chlorine, and algicide? If so, what?

Meanwhile, do NOT add anything except water, chlorine, borax or acid if needed, and algaecide (preferably, polyquat)

PoolDoc

[johnboy]

My bad on the chlorine reading it is .3 not .03. My tester is a Pentair 78HR.

Not sure what the cya was last fall. In the fall I drain the water down below the inlets and i have a drain in the pool wall that keeps the level from rising above the inlets during the winter. When I open the pool I insert the drain plug and fill with fresh water. When I opened the pool the ph was low ( 6-8 0r so) and I added a box of borax rechecked the ph and it was still a little on the low side so I added some ph plus that I purchased at wal mart. Once the ph was up to 7.2 I added the triclor shock and within a few hours it was gone. The only thing I have been adding is shock either in the liquid form or the triclor granular and ph plus because the ph keeps dropping. Not sure how often I should reshock and should I use bleach or triclor granular. I also have an automatic chlorinator that I have 3" tablets in Thanks for your help

[Watermom]

I wouldn't use any more trichlor in your pool since your CYA is 50. That is a good level and trichlor will cause your CYA level to go higher which you don't want. It is also very acidic which is why your pH is dropping. Stick with bleach. In a 35K pool, each quart of 6% bleach will raise your chlorine level by about 0.4. With a CYA of 50, you'll want to try and shock the pool up to about 15ppm and try and hold it there until you can go from sundown one evening til sunup the next morning without losing more than 1pm of chlorine. Since this is such a large volume pool, if you have access to some 12% hypochlorite, you can use it instead of bleach (which is 6% sodium hypochlorite). Test 2-3 times per day and each time, add enough chlorine to take it back up to 15. There is no such thing as testing and dosing too often while you are trying to clear a pool. The more often you do so, the faster you can get it cleared up. Keep an eye on your pH and make sure it stays above 7.0. As Ben said above, don't add any other things. Some pool stores will try and sell you numerous products that "will fix the problem" but in actuality, will just make it worse. Keep us posted how it is going.