Cloudy water - enormous chlorine consumption

Sep 18, 2008
16
Hi all. This is my third summer on a new pool. I started getting ready to open my pool a few weeks ago. So I started my heater and then ran through the full range of tests (25K gallons):

Calcium 260
FC 1
CC .5
TA 70
PH 7.5
CYA 30

I shocked the pool and everything seemed fine (BBB 6%). No problems holding my chlorine level. The TA was a little low so I added some acid and then a few hours later I added some baking soda. This clouded the pool as I expected and was still cloudy the next day. I tested the TA and it was at 90 and the PH was 7.5. I then treated with polyquat.

The next day my chlorine had gone to zero. I threw in the robot and removed any remaining debris . The pool was still so cloudy I can't see the main drains. The pool walls are clean, no visible algae growth anywhere (no mustard), no debris. Backwashed before first shock and sand was clean.

I started to shock again today. I have been doing it all day and I literally can not continue with the shock because I ran out of chlorine after having depleted both Sam's club and Lowe's. I have added 32 gallons of 6% today alone. I think I had the FC up to 23 at one point. It literally drops 10 points within 2 hours. At one point I think my FC was 15 and CC was 1! I added my last 4 gallons about an hour ago. FC was at 11. 4 gallons should have taken it to 21. Measured 2 hours later and FC is 16. There is something wrong. I even swept around and checked for dead birds, squirrels, etc. After looking back at the Polyquat bottle I think I may have treated with a 40% thinking I had the 10% so I may have added way too much.

Any ideas or help would be appreciated.

I'm waiting for the FBI to show up at my door. When I went back the second time for another 15 gallons of Chlorine to the same cashier she started giving me funny looks and then got on the phone and whispered something.

Thanks.
 
Hi Michael,

If your FC isn't holding overnight, then you likely have algae or other organics in your pool that are consuming your FC.

You need to bring your water to shock level, which based on your CYA of 30 is around 13 ppm of FC, and hold it there, full-time, until your FC holds. You will know when you are finished when your FC loss is 1 ppm or less over night and your water is clear. All the while, you need to brush a lot, and backwash when your filter pressure rises reflecting sand bed saturation with dead matter.

Shocking your pool is a continuous process. Even raising your FC to 23 ppm once may not zap everything in there entirely. The key is maintaining that shock level fully and completely until you are finished. Bring your water to shock level and then check it 30 minutes later to see how much you've lost. Then immediately replace it, wait 30 minutes, and check it again. Repeat this process over and over until it holds.
 
Thanks. That's what I have been doing all day. I just don't know that I can find a source of chlorine that will allow me to maintain FC level. I have had the FC above 15 nearly but ran out of chlorine after 32 gallons. I actually had another 2 or 3 gallons of 10% before that. It's dropping nearly 5 points in 30 minutes. If I had more chlorine I guess I would have to stay up all night to complete the shock. My filter pressure has not risen once through this whole process and I have been sweeping all day. Yesterday I even dosed the pool with some Clear Blue clarifier thinking that would help removes some of the fine debris my filter wasn't catching. Still no pressure rise on filter. I started the backwash once just see if the water was dirty and it came out clear.

Don't get me wrong, I'm not questioning your advice. I'm new at this. I just want to make sure it seems reasonable that I would have enough organics in the pool to consume that much chlorine and I need to just keep going? I'm going to have to have to start pumping water out to make room for the chlorine soon :-D.
 
Bringing the FC up higher than the nominal shock level isn't necessarily helpful, at least not during the day. (Losses to sunlight get higher, although 10ppm in 2 hours seems like a lot.) If your CYA was 0, I might suspect ammonia, but my understanding of the CYA->ammonia process is that it goes pretty quickly and you said you still had CYA.
--paulr
 
Hi Michael, some of my comments are in bold scattered in your post....

MichaelCombs said:
Hi all. This is my third summer on a new pool. I started getting ready to open my pool a few weeks ago. So I started my heater and then ran through the full range of tests (25K gallons):

Calcium 260
FC 1
CC .5
TA 70
PH 7.5
CYA 30

I shocked the pool and everything seemed fine (BBB 6%). No problems holding my chlorine level. The TA was a little low so I added some acid and then a few hours later I added some baking soda. This clouded the pool as I expected and was still cloudy the next day. I tested the TA and it was at 90 and the PH was 7.5.
TA of 70 and PH of 7.5 is perfectly fine - adjusting them was unneccessary.
I then treated with polyquat.

The next day my chlorine had gone to zero.
Using algaecide will consume chlorine, especially PQ, and possibly the clarifier too...

After looking back at the Polyquat bottle I think I may have treated with a 40% thinking I had the 10% so I may have added way too much.

I don't think you used Polyquat - Polyquat 60 says 60% I've never seen it in 40% or 10%. Can you please tell us the active ingredient on the lable you used?

If you used too much, this explains the FC demand and it will eventually go away, by continuing to hold shock level.


Any ideas or help would be appreciated.

I'm waiting for the FBI to show up at my door. When I went back the second time for another 15 gallons of Chlorine to the same cashier she started giving me funny looks and then got on the phone and whispered something.

Thanks.

Michael - I would seek out a Pool Store source for 12.5% - less jugs to carry, and often their price is better. Your demand will decrease as the chlorine works on the algaecide just have some POP, I agree with Paul - it's not necessary to go higher than shock level. :wink:

Now, 6% Clorox is not sold in gallons. The jug sizes are 96oz and 182 oz. So make sure you are calculating correctly when using the pool calculator. The stronger stuff, 10-12.5% is usually sold in gallons. Just wanted to point that out. Also is it a different brand from Lowes, or is it Clorox as well?

PoolGuyNJ said:
Changing the sand, drop the pH to 7.2 and using 10 gallons12% if available is all I can think of at this point. Drastic but seemingly needed.

I assume you checked the skimmer baskets and pump basket.

Scott

I think this suggestion of using 10 gallons is extreme and probably wasteful, if you intended for Michael to add it all at once? as it would raise the FC up to 50ppm... (this is not clear from your post). I also don't see the point in changing the sand.
 
Well, I kept the FC level at 15 until I fell asleep at 4am. I woke up this morning and I still had the test bottle in my hand. This morning the FC was 12 and cc about .5. The rate of consumption appears to be slowing.

I brought the FC up higher thinking I might have Mustard Algae or something and just wasn't seeing it even though the walls and all the cracks and crevices in the pool are completely clear. We had heavy cloudcover too so not a lot of sunlight.

Thanks for the tip on the TA. For some reason I was thinking 90 was the target. I didn't realize Polyquat consumed chlorine either. I was using the term generically because I believe the main ingredient is the same. The active ingredient in my gallon of Pool Brand Algaecide is alkyl-dimethyl benzyl ammonium chloride 40% (Sam's club). I did indeed grab the 40 instead of the 10 so I put in 4 times too much after the first shock, but that was several days ago.

I get 6% gallons at Sam's club. It's Proforce Commercial Bleach 4 to a case. At Lowe's I get 1.5G RedMaxx Germicidal Bleach. None of the pool stores around here carry liquid chlorine, in fact, if you ask they give you dirty looks and practically run you off. There is a pool service near me that will sell 10% but they want $6 a gallon and are frequently out. The local Ace hardware has 10% gallons as well but they only carry about 5 at a time, restock every two weeks and it's a little more expensive. I grabbed Chlorox last night at Walmart since I had bought out the 8 cases of Proforce from Sam's and Lowe's was out of RedMaxx.

Fortunately there is a recycle drop near me. Currently I have two large 75 gallon stretch trash bags full of empties. I'm in OKC if anyone out there knows where I can get stronger stuff.

Thanks again for all the help.
 

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MichaelCombs said:
I didn't realize Polyquat consumed chlorine either. I was using the term generically because I believe the main ingredient is the same. The active ingredient in my gallon of Pool Brand Algaecide is alkyl-dimethyl benzyl ammonium chloride 40% (Sam's club).

The main ingredient is not the same, and this is called a linear-quat. It's less expensive and less effective and won't last as long as true PQ60. It can also cause unwanted side effects like foaming.

Polyquat 60 is "Poly[oxyethylene(dimethyliminio)ethylene(dimethyliminio)ethylene dichloride 60%" as the active ingredient (For future reference.)

Either way, continue to shock - and your FC will begin to hold. :)
 
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