Cannot maintain FC levels w/ BBB

[Watermom]

Yes, but she will probably want to wear on old swimsuit that she won't care if it fades some.

[Slachey]

Great. Thanks again. I love this site!

[Slachey]

Good morning.

My wife checked the FC level at 6pm last night and it was 7.8. She said the tested water only turned a very light shade of pink when adding the 5 drops of R-0003. That indicated to her that the CC level was near 0. She added (3) 121 oz jugs of 8.25% bleach. When I got home at 11pm I tested and the FC was 20, and similar to my wifes testing of the CC, the water only turned the absolute slightest shade of pink, so I added 1 drop of the R-0871 and it became colorless. This indicates to me that the CC is near 0. This morning at 7:30 I tested again. The FC was at 18 and the CC was similar to the night before.

So it looks like I lost ~ 2 ppm of FC (assuming a slightly incorrect reading as I tested a couple hours after sunrise).

I did not have a chance to scrub the floor and walls as Watermom suggested and there are small areas of brownish, greenish, yellowish patches sporadically on the pool floor.

What do you guys think?

[Watermom]

Keep the chlorine high again today and brush. I would go ahead and repeat the test tonight.

[Slachey]

Thanks for the quick reply Watermom.

Since the FC is currently at 18, do you recommend that I immediately bring it back up to 20, and ensure it is at 20 pretty much throughout the day and when I test tonight? Or am I ok keeping it in the 18 to 20 "range" throughout the day?

Note that on the pool math calculator, it states with a CYA of 100 that my normal FC range should be 8 to 13 and 39 for shock. With this said, should I go with a higher FC level to ensure I eliminate anything that the FC could be fighting?

[Watermom]

Is the CYA reading 100? Your previous post said 90. 18-25 would be ok but I wouldn't go to 39 especially since you have a vinyl pool. (Not sure where you got the 39 from?)

[Slachey]

Thanks Watermom.

My wife tested the CYA at 90, but I tested at 100. This is a tough test for me, as the disappearance of the black dot is a bit subjective. Must any resemblance of the dot be completely gone including any shadowing?

The FC of 39 came from a Pool Math Chart on Trouble Free Pools. It stated that with a CYA of 100 that my "normal" FC should be in the 8 to 13 range, "shock" is at 39, and "mustard algae shock" is at 54. Sorry if I am mixing apples and oranges and you guys do not follow this.

[Slachey]

Thanks PoolDoc.

Watermom,

No offense taken at all. As mentioned, this site and the replies to my issue have been a great experience so far. I am leaving again for the evening so I added 2 gallons of 8.25% bleach. My FC was down to 13.8 this evening (No CC) from the 18 I measured this morning.

I'll test when I get home tonight and again in the AM.

I hope this stabilizes soon!

Thanks again.

[Slachey]

So I added (2) gallons of 8.25% bleach at 6pm on 6/28 when the FC was at 13.8. I got home at 10pm and the FC was 18. I checked at 6am the next morning and it was at 17. I did not add anything all day yesterday and checked the FC at sundown last night (~ 8:15pm) and the FC was at 12. It lost 5 ppm of FC all day. I checked again this morning at 6am and it was at 10, so it lost 2 ppm overnight. I added (2) gallons this morning hoping to get it up to close to 20 again for the day.

The CC is reading 0, so I am a bit confused as to what I am to do next. The pool is taking at least (1) gallon per day to "maintain" FC level.

Any additional help would be appreciated.

[Watermom]

I don't think you are in 'maintenance' mode yet. I still think you are fighting something in the water.

At 6pm Saturday night you had 13.8. Adding 2 jugs (I assume they are the 121-oz. and not gallons) would have added 9ppm which would put you at 22.8. Four hours later at 10pm, you had already lost 4.8. Then, you lost another 1ppm overnight. So, you actually lost 5.8 from sundown to sunup which is the time period we look at. (When you lose chlorine in the evening when there is no sun on the pool, it is lost due to oxidizing something in the water. When you lose it during the day, part of the loss is to the sun.)

It appears that your chlorine loss is lessening so hopefully you are getting close. I know you are getting frustrated but hang in there. I have a feeling that you are nearing the end. Report back in the morning.