Decontaminating my Spa Right Now - How Long

[geekgranny]

Fiberglass spa with, I guess, acrylic finish, 7 yrs old. I've got the Cl up to 100. BBB but just started from ionization/Nature 2/ozone/MPS and a little chlorine.

We just had a neighborhood emergency so it has been at that level circulating for 2 hours.

How long is it safe to keep 100 and decreasing Cl in spa without doing any damage to anything?

BTW.... I'm fighting white/brown hunks of slime that keep coming out even after two super flushes within past three months. I understand that it spa is "infected". That's why I'm decontaminating.

Thanks, gg=alice

 

[geekgranny]

Help

I've still got decontamination levels of Cl in spa. Is this going to damage anything?

 

[chem geek]

I would not keep it that high for more than 8 hours and normally it's only 30-45 minutes at that high level. Using either Dichlor or bleach for the decontamination results in roughly comparable active chlorine amounts due to the CYA in the former case and high pH in the latter case. The net result of around 14-20 ppm FC equivalent with no CYA at pH 7.5 is to be compared to the more typical spa levels that are equivalent to around 0.1-0.2 ppm or so. Basically, it means that your chlorine exposure is around 100 times higher than normal so 8 hours would be 800 hours or roughly one month of exposure while 30 minutes would be around 2 days of equivalent exposure.

So it's not a disaster by any means, but not something you should keep in the spa for longer than necessary. See the decontamination procedure here where the 100 ppm is only for 30-45 minutes while it is 10 ppm that is for 8-12 hours.

 

[geekgranny]

Thanks so much. I was beginning to freak out. I started the 100ppm around 1500 so it has now been a little over 6 hours. I'll go out in a bit to add and drain water then keep circulation going all night and deal with finishing tomorrow. I've kept the new cover propped open for off gassing.
gg=alice

 

[geekgranny]

Thanks so much chem geek. I was able to sleep well that night. I drained more than half the water and refilled to continue in a.m. Although the Cl was still really high, after partial drain and refill, I wanted to keep it really high as I've been battling the brown/white clumps of biofilm coming from lines for a few months now. The two previous flushes using a Spa Flush, which I did for over 24 hours, for each, using twice the recommended amount for second didn't totally get rid of the biofilm. Last month I developed a pretty resistant bladder infection that took a round, each, of two different antibiotics to clear up.

I think this decontamination, using recommended procedure WORKED. And the water is fabulous. Just in time for DH (hubby) to "reactivate" himself after an unusually long and hard two weeks.

Following procedure I took the Cl up using Dichlor to 10 and ran for 24 hours. It dropped to 8 during that time. I have two sources of aeration that I don't want to stop. That is the Ozone return and main return from circulation pump which run 24/7. I did unplug the Ozonator so its return is only air. Also the top was off some with strong sunlight hitting it so I don't think the drop from 10 to 8 was very significant.

Yesterday I added all chems that were needed and recommended Borax. Last night I ENJOYED a 2 hour soak in fabulous water and NO Sign of biofilm. Also wasn't dried out after the soak and only needed night time face cream instead of full body lotion as before.

I ordered refills for CYA reagent and borates strips from duraleigh that should be here today or tomorrow. :-D I'm out of CYA reagent. I had done the initial Cl addition with Dichlor but had on hand a few lbs of CYA so figuring from Calculator what the initial CYA would be from the Dichlor I then added CYA using a stocking in front of the circulation return.

Question - The CYA dissolved out of stocking in less than three hours. The circulation pump is on 24/7. How long will it take before I can get an accurate reading of CYA?

Our spa is used heavily by DH and me. I rarely soak for less than an hour and sometimes take naps in spa. No worry, I'm a fish and sleep lightly. His soaks are usually for more than an hour. He actually likes to sun bathe in the spa. I have four cartridge filters (1 @ 1yr, 1 @ 6 mo, 2 @ < 2 months) and was changing them out several times a week due to biofilm. Now that biofilm is GONE I can probably go back to filter change out once a week. I did soak all filters in chlorine/water 1/10 for several hours each.

BTW.... I informed DH that he does not need to use the "water softener" any more due to the borax. YEA

All is well. Thanks TPF and all you great guy n gals. :-D :-D :-D

 

[polyvue]

The CYA dissolved out of stocking in less than three hours. The circulation pump is on 24/7. How long will it take before I can get an accurate reading of CYA?

Since the spa is a much smaller body of water than a pool, it would seem that the cyanuric acid would be detectable far sooner than the 3 days to 1 week typical for a pool. But there may be some chemistry required to arrive at the proper answer -- the CYA binds to chlorine molecules, but not sure how the test for CYA turbidity measures this other than it's based on precipitating particles from solution. Sans chemistry, you could test this by measuring CYA at intervals following a one-time application: 6 Hours, 1 Day, 2 Days, 3 Days, 1 Week etc.

I rarely soak for less than an hour and sometimes take naps in spa. No worry, I'm a fish and sleep lightly. His soaks are usually for more than an hour. He actually likes to sun bathe in the spa.

You and DH live dangerously! Nevermind the chemistry; I just hope the water temperature is 100° F. or less. :grrrr:

 

[geekgranny]

The CYA dissolved out of stocking in less than three hours. The circulation pump is on 24/7. How long will it take before I can get an accurate reading of CYA?

Since the spa is a much smaller body of water than a pool, it would seem that the cyanuric acid would be detectable far sooner than the 3 days to 1 week typical for a pool. But there may be some chemistry required to arrive at the proper answer -- the CYA binds to chlorine molecules, but not sure how the test for CYA turbidity measures this other than it's based on precipitating particles from solution. Sans chemistry, you could test this by measuring CYA at intervals following a one-time application: 6 Hours, 1 Day, 2 Days, 3 Days, 1 Week etc.

Thanks much. My CYA reagent may have come in today but can't get out to pick it up. Will be here tomorrow for sure.

I rarely soak for less than an hour and sometimes take naps in spa. No worry, I'm a fish and sleep lightly. His soaks are usually for more than an hour. He actually likes to sun bathe in the spa.

You and DH live dangerously! Nevermind the chemistry; I just hope the water temperature is 100° F. or less. :grrrr:

Yeah, we keep it right at 100 except during really hot times. It heats up if the jets (each side with 5.5 hp pumps) are running for long; less when only one so we have to use bubbler to keep temps down in summer. In winter less of a problem. We usually run venturi on all jets for "harder" flow which helps it to cool a bit. When it's really, really hot, 98 or above we keep it at 98-99. Spa has several spots to sit for cooling and in summer I usually have a fan going on deck that sends a little breeze towards the spa. It's also windy out here most of the time. A still day is quite rare. I love to read in the spa but it is usually too windy to handle a book comfortably and relax at the same time.

Spa time for us, when we soak together is great couples therapy, too. I mean talking. :lol:

We've had spas for 23 years. Hubby 74 and I a quite a bit younger. Hasn't killed us yet. Neither of us have high blood pressure either so maybe that helps. I, also, do a lot of work outside in 100+ temps, hardly breaking a sweat so that helps. I do use aides such as hats, neck coolers, light weight clothing that I can wet, and following the shade as much as possible. I get chilled pretty fast in water that is less than 90.

gg=alice

 

[chem geek]

The rate of CYA dissolving is temperature dependent so it should dissolve more quickly in your hot spa. I'd guess that it will probably be fairly well dissolved in one day, but I could be wrong. I wouldn't worry about it -- if you added known amounts of Dichlor and pure CYA and calculated the expected result (around 30 ppm?), I'm sure it's fine.