Help !!!!!!!!!

[eddman]

This is a folow up to a post I had about TA.

Earlier this week I had been fighting an sudden uncommon cause algae bloom. On 06/08 I applied a cooper algaecide and shocked the pool. The next day the algae was killed off so I shocked again and applied a drop out. On friday 06/10 I vacced to waste, backwashed filter then added 2 gals of 6% bleach and 2lbs 65% cal hypo.
Earlier today I had the following readings:
FC 0
TC 1
pH 7.2
TA 150
TH 280
CYA 30

Tonight at 8pm I added 1218 oz/9.5 gals of 6% bleach.
At 10:30 pm I checked levels and they are as follows:
FC 0
TC 1
pH 7.2
TA 150
TH 280
CYA 30

Or the same as before the bleach except no FC .

What gives. According to all the pool calculators and such the FC should have been in the 12 - 14 ppm range. Was it too early to check...help...or am I just stressing over nothing or is there a problem I do not understand?

[madwil]

assuming that your pump was running, the bleach should have been readable.
Since it wasn't, 1 of 2 things
1- the test wasn't right; If your added more bleach than intended, the color can bleach out and show 0 even though it's 15+! 9 gallons of bleach addes 45 ppm FC in 10k gallons... how big is your pool? that much bleach would add 20+ to my pool! (26k gallons)
2- something is eating the chlorine- algae, ammonia (the algaecide could have had ammonia with the copper maybe?), etc...

Try the test again, diluting the pool water. if your pool is 10k gallons, use 9 parts clean water (distilled/RO, not tap) and 1 part pool, and see if you read FC... If still no color change at all, try with 4 parts clean water and 1 part pool water. The first gives a factor of 10, so reading 3-4 would really show 30-40 in pool. the second will give factor of 5, so reading of 3-4 would be 15-20... both these scenarios would possibly bleach out some tests.

[eddman]

My Bad

I think I found the problem with the FC/TC. I have had major algae problems this year and fighting them on and off. Several weeks before using the copper algaecide after unsucessful use of polyquats I had applied a different algaecide which turns out to have been a sodium bromide.

My NEW question now is how long is it going to take to get the this worked out of the water and what do I need to do to expedite the process if anything. I wish the manufacturer/distributor had been more diligent in supplying info on the imapct of sodium bromide to chlorine upkeep.

Thanks for all the help..maybe someone can show me a light at the end of the tunnel..........

[Watermom]

Since you have used sodium bromide, I'm going to ask Ben to take a look at your problem. He has more experience dealing with bromide.

[PoolDoc]

Hi Eddman;

You may have a sodium bromide problem -- but that's not the cause of your low chlorine reading, not when you added chlorine at 8pm and tested at 1030pm. Adding bromine increases loss to sunlight, but not otherwise.

How are you testing? Your results look bogus in a couple of ways.

Ben

[eddman]

hmm don't know what to say.

I am using drop/titrate test to check everything except for FC which I am just using a strip.

I am doing the readings twice daily and getting similar results everytime...

If I can i will pull a fresh sample tomorrow and take it elsewhere to see what they are getting for results and post them.

In regards to the sunlight the pool is inddors under a clear roof which blocks about 90% UV will still allowing light...

The pool is an inground 20 X 40 about 41,000 gal with a correct size pump and sand filter.

Any help/suggestions would be appreciated.

[PoolDoc]

OK.

Let's do this.


Buy a cheap OTO (yellow drops) chlorine test. On your pool, an 10 gallon dose of *plain* 6% household bleach will be about 15 ppm chlorine.
Add 10 gallons within 2 hours of sunset; test 1 hour later, again within 2 hours of sunrise, and again that evening.

The first test will verify your test method; the 2nd will see if you have a chlorine demand apart from sunlight, and the third will check to see if you really are blocking 90% of the UV.

Plus, 15 ppm is enough to do some good with your algae, if your CYA test results are correct.

Ben

PS. Consider getting a DPD-FAS testkit. It would make it much easier to tell what's going on, because it is the ONLY way to accurately measure chlorine levels in the 0 - 20 ppm range. (Link to Amazon sold kits below; wait a day if "Amato Ind" is not the seller; other Amazon sellers sometimes confuse the K2006 with the non-FAS-DPD K2005)