How risky is cloudy water?

Spatropy

Member
Dec 24, 2022
19
Richmond CA
Pool Size
150
Surface
Fiberglass
Chlorine
Liquid Chlorine
Came home from a trip to find my hot tub had had gone cloudy/milky. This has happened before when I'm not on top of adding the bleach. I'm assuming it's either algae or bacteria...

Question is: how safe is it to go in the tub? Let's assume I brought the FC up to 10 for 15-30 minutes. Is that a health risk?
If so, is 12 hours unsafe even if still cloudy?

Nobody else uses this tub but my wife and me, so I don't have to worry about unknown user factors like kids with diahhrea, etc. I don't know about Legionnaires’ disease: does that need to come from somebody who has it or does that bacteria spontaneously occur in untreated water?

Thanks!
 
I am not a medical professional but I would not go into a cloudy pool or spa that has questionable sanitation.

Clear water with the proper chlorine level indicates sanitary conditions.
 
I think I would be less likely to go into a cloudy pool, but if I'm not putting my head under the water in a hot tub, I'm not entirely sure of the threat. I understand that not going in is always the safe choice, but not using a pool or hot tub is even safer. So I'm just trying to understand the relative risk level and what those risks might be.
 
Question is: how safe is it to go in the tub? Let's assume I brought the FC up to 10 for 15-30 minutes. Is that a health risk?
If so, is 12 hours unsafe even if still cloudy?

Totally depends on the CYA level. If the CYA is zero then it would be over chlorinated and unsafe to enter. If the CYA is 200 then it’s under chlorinated and also unsafe to swim/soak.
What are the water test results?
 
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Well if you really want to know...Legionnaires’ disease
While unlikely, as you have to inhale droplets to get it into the lungs...it does drive the conversation that there can be pathogens floating around in the air, that land in the spa/pool and find it a nice place to grow. My personal guess is that odds of having an issue are pretty low - unless one gets bacteria in a cut/wound or aspirates the water. People swim in ponds, streams and lakes. But there is a chance...

My State Health Dept. advises for water systems to use a concentration of between 50-200 ppm, let it sit for 6 hrs to overnight, then completely drain, rinse, and fill with fresh. But that gets hard with a pool. If do-able with your hot tub, would be the best route. The SLAM method for pools noted on this site is a lower and slower version of the same thing - with less Cl, it just takes longer to make sure everything is dead. Can't tell you with a hot tub how long, but it won't be hours. Likely a few days. Going to 10 probably will be ok. But note my use of "probably". Going to 50-200 wouldn't, so that would be a stay-out situation. Does the hot tub even have a filter to capture the floating dead stuff, or will you have to drain to get rid of the debris that any form of sanitizing will leave behind?
 
Well if you really want to know...Legionnaires’ disease
While unlikely, as you have to inhale droplets to get it into the lungs...it does drive the conversation that there can be pathogens floating around in the air, that land in the spa/pool and find it a nice place to grow. My personal guess is that odds of having an issue are pretty low - unless one gets bacteria in a cut/wound or aspirates the water. People swim in ponds, streams and lakes. But there is a chance...

My State Health Dept. advises for water systems to use a concentration of between 50-200 ppm, let it sit for 6 hrs to overnight, then completely drain, rinse, and fill with fresh. But that gets hard with a pool. If do-able with your hot tub, would be the best route. The SLAM method for pools noted on this site is a lower and slower version of the same thing - with less Cl, it just takes longer to make sure everything is dead. Can't tell you with a hot tub how long, but it won't be hours. Likely a few days. Going to 10 probably will be ok. But note my use of "probably". Going to 50-200 wouldn't, so that would be a stay-out situation. Does the hot tub even have a filter to capture the floating dead stuff, or will you have to drain to get rid of the debris that any form of sanitizing will leave behind?
With a CYA of 126ppm, it’s perfectly fine to swim/soak with the FC all the way to 50ppm which is the SLAM level for a CYA of 126ppm.

Increasing FC to 10ppm without any CYA in the water would be unsafe as there’s too much HOCL in the water.

 
Well if you really want to know...Legionnaires’ disease
While unlikely, as you have to inhale droplets to get it into the lungs...it does drive the conversation that there can be pathogens floating around in the air, that land in the spa/pool and find it a nice place to grow. My personal guess is that odds of having an issue are pretty low - unless one gets bacteria in a cut/wound or aspirates the water. People swim in ponds, streams and lakes. But there is a chance...

My State Health Dept. advises for water systems to use a concentration of between 50-200 ppm, let it sit for 6 hrs to overnight, then completely drain, rinse, and fill with fresh. But that gets hard with a pool. If do-able with your hot tub, would be the best route. The SLAM method for pools noted on this site is a lower and slower version of the same thing - with less Cl, it just takes longer to make sure everything is dead. Can't tell you with a hot tub how long, but it won't be hours. Likely a few days. Going to 10 probably will be ok. But note my use of "probably". Going to 50-200 wouldn't, so that would be a stay-out situation. Does the hot tub even have a filter to capture the floating dead stuff, or will you have to drain to get rid of the debris that any form of sanitizing will leave behind?
Sounds like the bacteria isn't transmitted person to person, but occur naturally in water systems.
Yes, has filter, so can take care of debris.
Thanks!
 
With a CYA of 126ppm, it’s perfectly fine to swim/soak with the FC all the way to 50ppm which is the SLAM level for a CYA of 126ppm.

Increasing FC to 10ppm without any CYA in the water would be unsafe as there’s too much HOCL in the water.

Thanks, that's an interesting read. CYA level is 25
 
So I'm just trying to understand the relative risk level and what those risks might be.

there is a chance...

like the bacteria isn't transmitted person to person, but occur naturally in water systems.
The two are not mutually exclusive, nor are they the only 2 ways.
Just to be clear, cloudy water can be the result of other issues including water balance, filter condition, cycle times, and equipment malfunctions.
Guessing is moderately less reliable than test strips, and immensely less than a good test kit. That said, depending on your location, dumping and starting over is often the best, and in some cases the cheapest, option.
Most likely you will not have any issues, I've had to touch countless nasty tubs, however the issues that you could have include some very nasty stuff that you don't want, and may be incurable. So I guess the question is: Do you feel lucky? I wouldn't get in it.
 

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Raise fc to slam level for your cya
FC/CYA Levels
(Cya of 25 counts as 30 for chlorination purposes.)
& keep it there until the water is clear & cc’s are .5 or less. Before using the tub. This can take many rounds if it is milky as you described & many people find its not worth fighting it.
Or just do an Ahhsome purge then drain and refill starting fresh with this guide
Generally- No sense in fighting with 150 gallons of water. Dump it.
Legionnaires is real & deadly , hot tub rash is real & painful, I would not use the tub until you did one of the above things.
If you travel often or are away from the tub you may consider a swcg to provide standby chlorine.
Saltron mini or controlOmatic.
Test Kits Compared
 
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I'll bow out of this thread, as I really don't have much knowledge about hot tub care and feeding....

But, from earlier threads, it appears that the OP's tub is 150 gal. Hit it with high Cl (50 ppm) to sanitize everything, stay out for 6 hrs, drain, refill with fresh, and rebalance the water. Start this morning, be soaking this evening. It's only 3 conventional bathtubs of water that is trying to be preserved here...
About the same water usage as when I sanitize my RV!

Just ignore me if I am profoundly displaying my ignorance on the subject. :)
 
I'll bow out of this thread, as I really don't have much knowledge about hot tub care and feeding....

But, from earlier threads, it appears that the OP's tub is 150 gal. Hit it with high Cl (50 ppm) to sanitize everything, stay out for 6 hrs, drain, refill with fresh, and rebalance the water. Start this morning, be soaking this evening. It's only 3 conventional bathtubs of water that is trying to be preserved here...
About the same water usage as when I sanitize my RV!

Just ignore me if I am profoundly displaying my ignorance on the subject. :)
The 50ppm fc isn’t necessary & possibly destructive but you’re on the right track. Slam level fc (in op’s case 12ppm) —> ahhsome purge to remove biofilms then dump & refill.
You are correct about 150 gallons- not worth fighting.
 
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