It all started with a sparkly pool and a green spa...

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poolinthewoods

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Sep 1, 2014
12
The Woodlands, TX
For three years I have been caring for my pool using the BBB method and you have no idea how much I appreciate the knowledge you have shared. I had never had any trouble but I am now stumped and hope you will share your insight. I do ask for your patience as I may not be as well-versed when it comes to equipment terms. Apologies in advance for the length of the post.

Our pool has a spa with a spillway, and while we swim regularly, the spa is seldom used (and I must admit is neglected at times with leaves sitting at the bottom for longer than should be). Yesterday our pool was its sparkly self when I noticed patches of algae on the walls of the spa. I proceeded to shock the spa as per Pool School protocol, but thought it best to turn off the filter pump to the pool and turn on the spa mode only- I figured it was easier to shock the contained spa water. The numbers were as follows:

20,000 gal. Pebble Tec (Houston area)
FC: 4
CC: 0 (pool)
pH: 7.4
TA: 90
CH: 250
CYA: 30
Water Temp: 89 / Cloudy Weather
TFT FAS/DPD chlorine test
Taylor K2005 for everything else

Confession: I only tested the pool water; I did not test the spa. I just assumed that I needed to raise the chlorine to 12, so I proceeded to add bleach to the spa, however, when I tested the spa water after dosing, it showed a FC of 0, and CC a dark amber (I figured it would be useless to waste reagent to try to figure out what it was). I thought that the bleach was used up by the algae, so I added more. I kept testing, and adding more and more. The spa water became clear, but yellow, while still testing at 0 FC, and still amber CC. I then became concerned that I had added way more bleach than I should have for such a small volume of water (9ft round spa) so since the water was clear (albeit yellow), I returned to regular pool mode. I tested the pool water at this time and it gave me a reading of FC: 30 (!). While I was concerned at how the chlorine had gone up in the pool, I was relieved knowing that at least the level would be high enough to do away with any organics spilling from the spa. However, I tested again one hour later and the FC was 0 (!!), and CC amber. I just tested and indeed FC is 0, CC somewhat lighter yellow color. The spa now looks back to normal, the pool is clear; it is hard to gage the color since the sun has gone down, but it looks very slightly green.

Please give me your impressions on how you think I should proceed. Are the FC/CC readings off because of the ridiculous amount of bleach I added? Or do I trust that in fact my pool water has 0 chlorine and organic matter in it? Could the FC really have swung from 4 ppm to 30 ppm and then to 0 ppm? If I added bleach to the spa only, how did it get to the pool?

Thanks for your help.
 
Are all the FC and CC levels you mention measured with the FAS/DPD test? It doesn't sound like it, since you mention an amber color, and the only color that show up in the FAS/DPD test is pink... were those tests perhaps done using the DPD test, which I think is part of the 2005 kit? My recollection is that that test bleaches out (no color) when you get much above about FC 5, so it is not good for measuring high chlorine levels. If you added a lot of bleach, you were probably above the range of the test.

See post #3 in this thread:
http://www.troublefreepool.com/threads/24188-Extended-Test-Kit-Directions

Or, were you using an OTO test for most of your readings, which does go from yellow, to darker yellow, to orange as chlorine levels go up (not sure, though, how that particular test would give you FC 0 values)?

Was the one reading of FC 30 obtained with the FAS/DPD test?

I'm a relative novice at all this, so perhaps I'm missing something very obvious, but your description of test results seems unclear as to which chlorine test you were using.
 
Thank you for your reply singingpond. All chlorine tests (including the 30 ppm result) were done using the FAS/DPD from TFTestkits, and the color was definitely yellow.

I am now thinking that perhaps what is happening is what chem geek (Richard) described in an old thread, where lack of FC in the spa caused bacteria to grow, it converted CYA into ammonia, and that the high demand for chlorine is due to the chlorine oxidizing the ammonia. I happened upon that post much too late last night, and unfortunately I cannot address it until late afternoon today. I plan on getting an ammonia test from the pet store, and re-testing the CYA. Hopefully if I can still register ammonia and see a drop in my CYA, the mystery will be solved. I think (?!)
 
The FAS-DPD test is where you add powder to the water which would make it pink if there was chlorine in the water and you then count drops until the water is clear. There is no yellow/amber.

The yellow color-matching test that is by the pH test is the OTO chlorine test and generally only shows you the total chlorine level.

Does you spa water not mix with the pool water? I would set you valve such that the spa is always mixed so that you only have one body of water to deal with maintaining.

At this point you need to follow the ShockLevelAndMAINTAIN Process on the whole pool/spa I would think.
 
I've been using the FAS-DPD for three years so I am familiar with it. Upon adding the heaping scoop of powder there is a tinge of pink which disappears in seconds- even before I swirl to mix. It is when I add the R-0003 DPD #3 reagent to detect CC that it turns yellow... and I mean yellow (no doubt about it).

The spa and the pool water do mix. Thus adding to my confusion.

I have "SLAMed" successfully in the past (twice, I'm embarrassed to admit). I am stumped now because no matter how much bleach I add, it still is not registering, certainly not anywhere near shock level (12 for my CYA of 30); this had never happened before. That's why I was thinking the bacteria-CYA-ammonia situation was happening.
 
If the FC level is high, you may not be adding enough powder to start. If you see pink and it goes away, I think you need to add a second scoop.

How old is your kit? I have never seen the water turn yellow in the FAS-DPD test.
 
I got the kit for the beginning of summer, and it is kept indoors in the shade. The weird thing is that when tested the pool water (before I started trying to raise the FC) it was 4; right before I opened up the spa to mix with the pool water it was 30 (remember I initially had it on spa mode only thinking it would be easier to shock); and when the water mixed it was 0. I have no reason to doubt the test. In the meantime, given the situation, I continue to add bleach, even though I cannot get the chlorine to register.

But at this point it can't hurt.... I will try the second scoop!
 
Certainly sounds mystifying! Maybe worth using an OTO chlorine test as a sanity check -- it would at least tell you if you have some chlorine, lots of chlorine, whatever -- a ballpark idea anyway.

You say you have no reason to doubt the FAS/DPD test... but, weird results and unusual colors from the reagents (the yellow/amber shades you describe) would certainly make me doubt the test in my hands. I'll be curious to hear if adding more of the powder will give you clearer results.
 

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Could the amber color be "through the roof" CC levels? That is the only level that I would consider not believable, since I stopped adding the R-0003 DPD #3 reagent because it was not changing color at all.

After the initial posted numbers all I have checked is the FC level and again, it continues to show 0 (even this morning). I will do a full set of numbers as soon as possible, but I hope you understand that I am reporting what I am seeing.
 
The FAS-DPD test should only ever be pink. You also should only add 5 drops of the R-0003 for the CC test and then add R-0871 to count the drops.

The most logical explanation for this is that the yellow capped R-0003 reagent for the CC test got switched with the other yellow capped R-0600 reagent for the OTO test. Using the R-0600 would turn the water yellow.
 
Thanks for the follow up singingpond. Truth be told, I hesitated in posting the numbers since if I was the reader, I would probably not believe them either. So here goes nothing. Please note that I was careful with the testing and I am sure no errors were made.

After my last post, the FC levels continued to show 0 and so I continued trying to get it to register by adding more and more bleach (8.25%). On 9/2 the morning reading was STILL 0 so I added 3 more gallons (total 16 by now since the beginning). That evening's test showed a FC of 40. That's right. Forty (80 drops of R870 x 0.5). I then started to panic, thinking surely I was going to melt some pipe somewhere and started adding fresh water trying to dilute it. By the way, the CC test was still showing yellow. And yes I added the correct reagent. Due to life, I never made it to the pet store for the ammonia test. I did not sleep that night. 24 hours later (last night) the test is as follows:

FC: 12
CC: 0 (completely clear- no yellow, no pink)
pH: 7.7
TA: 120
CH: 250
CYA: 0 (clear)

I think I got too caught up chasing the 0 FC and neglected to step back and look at the bigger picture after adding so many gallons of bleach. I am guessing I may have had algae and bacteria in the spa, and somehow it did not spill onto the pool (perhaps bacteria in the plumbing?). I do believe some of what was described by chem geek (in the link I provided) was happening since my CYA is now gone. I think I overwhelmed the pool with the bleach (for the initial CYA of 30, shock would be 12 ppm), and maybe such a ridiculous amount (40 ppm!) shows amber when adding the reagent for CC. I assume the spike in the TA was also caused by the added bleach. And I cannot even begin to comprehend how the FC was 0 in the morning and 40 that evening.

Now the water looks crystalline and the spa is pristine (I had not realized how dull the spa had been until now). I am sure no living organism is in the water right now- I just hope I didn't fry the equipment!
 
If you don't use your spa you still need to cycle the spa's floor drains (spa only mode usually), jets and blower. I have mine programed to turn the spa only on once a day for 15 minutes and have the spa jets to turn on for 5 minutes and blower for one minute. This gets fresh chlorine into all the pipes once a day.
 
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