Chlorine Lock ????

[chem geek]

Borates are a rather weak algaecide. They do inhibit algae growth a little, but if the chlorine demand in this particular case is due to algae, I doubt the borates will help enough to make a difference. If this is truly nascent algae growth, then a costly but effective way to stop it is with a phosphate remover, but that's a last resort (a copper algaecide would also work, but then you've got copper to deal with).

The nature of this problem, with FC rapidly consumed, CC rising and then dropping (even at night and rather quickly), sounds very much like ammonia. I went through the posts in this thread and it sounds like anhydrous ammonia was possibly added to the pool. This was a pool opened upon startup which is typically when an ammonia problem can occur after soil bacteria convert CYA into ammonia. I did not find an earlier post with an ammonia measurement -- only yesterday's post that said it was tested for ammonia and was negative. I wouldn't trust the pool store numbers at all.

poolrescue30, if you still have your own ammonia test, test the water again for ammonia. If you do not have such a test, please get one at a pet/fish/aquarium store. The ammonia test is inexpensive. Do not trust the pool store for measurements. The rapid drop in TA from 160 to 16 in 10 days and then to zero three days later makes no sense whatsoever (a zero TA in the normal TA drop-test showing up immediately red instead of green would mean the pH is 4.5 and is completely inconsistent with the reported pH of 7.1).

Richard

[CarlD]

Thanks, Richard.

[poolrescue30]

I did do the stick test for ammonia, I will pick up the other ammonia test kit they had in the store that uses drops and a color card , similar to the pool 5 way test kits. I know for sure I put in 3 gallons of ammonia on start up by suggestion of the new pool guy (who I don't use anymore). Can 3 gallons in a 33k pool , do so much damage ?? How do we get rid if it is ammonia, maybe we should treat it as such even with the stick test showing negative. ??

[poolrescue30]

Ok, update: I purchased an Ammonia test kit with the drops and color card , goes from 0-8ppm. I will do it as soon as I get home and test the FCL and TCL again.

[poolrescue30]

Ok, the reults are in :
On the Lamotte kit, FCL is .41
TCL is 1.45
On the FAS-DPD kit it turned a tinge pink when the dpd powder was put in, then 1 drop of R-0871 cleared it up , which should indicate .5 FCL , then 5 drops of R-0003 turned it pink , then 2 drops of 0871 turned it clear which should indicate 1.0 of CC , I don't know if that means we are coming closer to solving this, I did put in the 10 pounds of Calcium hypo into the skimmers at 10:30 am before leaving to a meeting , and the pool is cloudy due to the chemicals. I did these CL tests at 4:45pm, the Ammonia test came out with 0.25 ppm (mg/L) so I don't think ammonia is the problem. There is no visible algae, no alge on the floor. I'm going crazy .....Should I use 8 gallons of 6% bleach overnight ???

[CarlD]

Did you measure that FC tonight? Did all the Cal-Hypo dissolve (that's why it's cloudy--don't worry about THAT for now)?

If so, it's now evening, then add 5 gallons of LC...I think you are fighting the organic, whatever it is. Check your FAS-DPD test in the morning, too--BEFORE you add more. If it's come up, you are making progress. But you'll need to add enough LC to get it to the shock level.

PATIENCE!

[chem geek]

I know for sure I put in 3 gallons of ammonia on start up by suggestion of the new pool guy (who I don't use anymore). Can 3 gallons in a 33k pool , do so much damage ??

Ok, the reults are in :
the Ammonia test came out with 0.25 ppm (mg/L) so I don't think ammonia is the problem.

I don't know the concentration of ammonia that was used, but let's say it was 10%. That would be about 2.5 pounds or in your 33,000 gallon pool that's 9 ppm which is a lot and would require a cumulative amount of 90 ppm FC to get rid of. Also, you could have had ammonia before you even added it, from soil bacteria converting CYA into ammonia.

The fact that you are measuring even a little ammonia along with CC probably indicates that this was the problem -- but the good news is that you may be close to done! I'm keeping my fingers crossed.

Richard

[CarlD]

Ditto, here!

Thanks, Richard--the ammonia issue is a very, very unusual one for our members.

[poolrescue30]

Update: I had to be out of town yesterday till this afternoon.I had a friend pour in two 174 oz jugs of 6% bleach , last night at 6pm .This afternnon when I got back i took a sample to the pool store , it showed FCL 0.1 ppm and TCL 0.6 ppm, I hope that means the CC going down is a sigh the problem is going away , although i'm not keeping any FCL in thr pool ?? They suggested 3 lbs more Calcium Hypo into the skimmers and check 3 hours later and then 8 hours later on the FCL level . Does it make sense ???
Thanks

[CarlD]

I have told you before: the Cal-Hypo is not better than the liquid chlorine. It even may make your pool cloudy for a while until it all dissolves in, and it will raise your calcium level, which may be harmless.

But unless the Cal-Hypo is seriously cheaper, there's not any point to using it.

The reason they keep pushing it is that is what pool store clerks do. They see a bag of "Shock" and it's full of cal-hypo so they think that MUST be what you use.

But, as I said before: In your water, chlorine is chlorine. And Liquid Chlorine goes to work FASTER because it doesn't have to dissolve first.