No Chlorine at all in pool...

[markcobra]

Hello new to the forum, pool owner for 3 years never had any problems. 23,000 gallon concrete pool with D.E Filter. Pool is almost 20 years old. All chemicals are at ideal levels via strips and 3 pool store test readings except free chlorine and total chlorine reading 0. Pool water is crystal clear and no one has been in yet this season. I've been shocking with calcium hypochlor and maintaining chlorine tabs with stab in skimmer. I do get some alage buildup on walls. I shocked with 3lbs of calcium hypochlor and added 2 tabs today and tested with a strip half hour late and got good readings. An hour after that same great reading but no FC!

I have a Taylor 2006 on the way.

My latest reading from leslies compares to 2 other stores and strips

FC 0
TC 0
PH 7.6
Total Alk 120
CYA 30
Calc Hardness 160
TDS 500
Phosphates 300ppm I added pool perfect with phos free
Nitrates 2ppm

Please help this is driving me crazy. Never had a problem holding FC.

Is a partial drain and refill in order?

Thanks

Mark

[Watermom]

Here is your post. I'm not sure why you didn't see the other one. I modded it in earlier. (I deleted your duplicate post.)

Do you know what your CYA reading was upon closing in the fall? I believe your other post said that you have also been using dichlor this spring. Is that right? Did you have any CYA when you opened?

[markcobra]

Hi Watermom! Sorry for double post. I do not know the exact amount of CYA last year but remember that according to a test strip everything looked fine. I was using dichlor shock at the beginning of this season as well but again didn't measure any chemistry until water was clear. Thats when I kept noticing 0 chlorine reading even after shocking. I'm leaning towards ammonia now. I'm gonna get an ammonia test and check it out and then do a 2 gallon bucket test with Clorox Is there a certain type of ammonia test I should get?

[BigDave]

You can test for ammonia if you want to but I really don't see why. It's chlorine that will eventually clear it - the method for clearing it's the same. Get your pool to shock and keep it there until you lose less than 1ppm FC overnight and have nearly no CC. It'll take time and lots of chlorine but "it is what it is".

[markcobra]

Should I start with 12 gallons of liquid chlorine? 23000 gallon pool.

[markcobra]

I'm gonna buy 6 2gallon jugs of chlorine and dump it in the pool today. My Taylor 2006 test kit just came so I'm gonna test before I do anything and then burn out the ammonia or whatever is causing 0 FC. I did the 2gallon bucket test with bleach and it seems to be holding with a 1.5 tsp of bleach. I'll report back on results.

[BigDave]

Pool store Liquid chlorine at 12.5% Sodium Hypochlorite or household bleach at 6% Sodium Hypochlorite?

Looking over your post, I'm not sure if you have no chlorine or lots of chlorine as DPD and strips can bleach out in high chlorine. If you really have no chlorine then you probably have ammonia and I'll reccommend that you start going after it with lots of chlorine. But, if your chlorine is actually high, we'll need to figure out why you still have algae.

An OTO chlorine test will clearly tell us if you have no chlorine or really high chlorine. OTO/pH tests are widely available, pick one up before we go on.
If the Walmart's in your area have the HTH 6-way kit, get one. (Check availability) It has OTO, a better than average pH test, and other necessary tests

At a CYA level of 30, your shock level is 15 according to Ben's Best Guess Chart.
12 gallons of 6% bleach should put 32 ppm FC in your pool - probably too much but, a good amount to buy.
12 gallons of 12.5% LC should add 65ppm FC - Too much.

If OTO shows you have no chlorine, add 6 gallons of 6% or 3 gallons of 12.5%.

Please get the OTO and let us know if the test is clear (0) or Dark yellow, orange red, brown.

[Watermom]

Dave --- he states above that he has the Taylor K-2006 so there is no need for him to get the HTH 6-Way kit.

[markcobra]

Its been over an hour after dumping 10 gallons of liquid chlorine 10% and I attempted to test the FC chlorine but the sample wasn't clearing up after over 100 drops so I stopped. I did a test strip test and of course all the squares are off the charts. I hope I didn;t put too much in.

[BigDave]

Watermom, I posted while markcobra's post was still in mod queue.

markcobra, While the FAS-DPD test can be bleached out, it is far less likely than DPD or strips. Also if you put two scoops of powder in the the 10ml sample and swirl it you will porbably see a flash of pink before it bleaches out a third may turn it pink. No flash, no pink, no chlorine. No chlorine, go after it with bleach adding 6 gallons 6%, let it mix and then test - you should start seeing CC if you're fighting ammonia.