Cloudy hot tub water

Oct 6, 2018
42
Bay City, MI
Friday I noticed my water was cloudy and my fc .5. I added 1.5 oz chlorine. Saturday checked chlorine and it was .4 so I added 1.6 oz of chlorine. Last night went in it and added 2oz of non chlorine shock. This morning my testing results were.
FC - 5.6 ppm
total chlorine- .8
PH - 7.4
TA - 60 ppm
The water is still cloudy, I May be able to see a slight improvement. I can see the bottom. But it’s just not crystal clear. Should I add some clarifier? Or will it get better over time. Any suggestions would be appreciated.
 
Have you been using the tub often? What's your CYA level? What type of chlorine are you adding?

I assume you mean your CC is 0.8. Total chlorine is FC + CC and isn't very useful. Note that adding MPS falsely shows up as CC unless you get the Taylor add-on to remove MPS interference.
 
Sorry, I haven't really been posting the last few days. For a CYA of 40, you should be targeting a FC of 5-7, and never let it drop below 3. Is this what you are doing? You should also be adding bleach as soon as you get out of the tub, to oxidize bather waste. Try adding an ounce or two of 8.25% bleach for this addition.

I haven't had cloudy water myself, and haven't heard many other people have it in hot tubs, but generally for pools it's because things are growing (algae, etc). Does your hot tub stay covered? For this reason, usually clarifiers aren't recommended. If your water is still cloudy I'd bring your FC up to the shock level of 16 ppm and hold it there for a day or two to see if it clears up. And yes, you can still use the tub with a FC of 16 and a CYA of 40, just note your pH test won't be valid until your FC drops back down below 10.
 
The tub is normally covered. The cloudiness cleared up after adding more chlorine, cleaning the filter again and letting it run for about 5 hours. Using the calculator I try to keep the chlorine level at 5 ppm but the next day when I test it it’s at about.6 to .8 ppm. Where does the chlorine go? In the how to use CL in hot tub thread. It’s says to keep it between 3-6 ppm that’s why I shoot for 5 ppm. It also says to one a week shock it to 12 ppm. Should I use my RENEW product by Leisure Time. It’s a non chlorine shock instead of chlorine to shock it? My chlorine is 12.5%. Thanks for the help !!!
 
You will burn about 1.5ppm of FC per person per hour. I bump mine up to 7ppm before going in with CYA of 45ppm. I raise is back up to that level when we get out. There is a good link on this site from chemgeek that explains this in detail. I also use 50ppm borates to help with ph rise.
 
The tub is normally covered. The cloudiness cleared up after adding more chlorine, cleaning the filter again and letting it run for about 5 hours. Using the calculator I try to keep the chlorine level at 5 ppm but the next day when I test it it’s at about.6 to .8 ppm. Where does the chlorine go? In the how to use CL in hot tub thread. It’s says to keep it between 3-6 ppm that’s why I shoot for 5 ppm. It also says to one a week shock it to 12 ppm. Should I use my RENEW product by Leisure Time. It’s a non chlorine shock instead of chlorine to shock it? My chlorine is 12.5%. Thanks for the help !!!
Yup, so the cloudiness was caused by letting the FC drop too low.

Couple notes on the sticky: While the sticky does have good info, keep it mind it was written by a member as a summary, and since such a good job overall, it was stickied as a reference. It is also from 2008. So it is not be the end-all, be-all. Couple things come to mind, his FC, shock, and MPS recommendations.

FC: He says 3-6 ppm FC, min 1. The FC/CYA chart should be used based on your CYA level. He was assuming a CYA of 30, you are running close to 40. A CYA of 40 means target 5-7, min 3, shock 16. Note that even for a CYA of 30 the target is 4-6 with a min of 2. That's one issue with a long-lived reference, it never gets updated. So I'd stick to the FC/CYA chart for levels.

Shocking: A properly maintained pool/spa needs no shocking! This comes about from "traditional" pool recommendations. Now, a key point is properly maintained. This means trying to maintain the target level and never dropping below the minimum. You dropped below the minimum of 3 ppm for your CYA level, and that's why you got cloudy water, which might then take a shock to clear. Keep the FC up, and I'll bet a case of beer you won't ever have to shock again.

MPS: Though nitro seems to like MPS, it's 100% not needed. It can be used to help with CC's, but it has to oxidize the waste before the chlorine does to do this, which means adding before use or maintaining a level of MPS. Downside is MPS can't break down CCs after they form (only more FC can), it's expensive, and excessive buildup of sulfates isn't the best on metal heater elements. Biggest downside is it interferes with the CC test, falsely showing up as CC unless you buy a special regent from Taylor to neutralize it during the test. It also can't sanitize, only oxidize waste (which is why you always need FC, which can both sanitize and oxidize).

So, where is all the chlorine going? It's breaking down the yucky stuff from your body to keep your water clean! Sweat, urine, etc. chem geek recommends 5 fl oz of 6% bleach per person per hour of soaking at 104 °F. This should be added immediately after getting out of the spa, or even during your soak if you are doing a marathon soak. The amount needed needs to be adjusted for concentration (so 2.5 oz for your 12% bleach), temp (soaking at 98 °F as we do adds much less sweat and so needs much less added immediately after leaving), time in spa, and hygiene. If you go to the gym, get covered in sweat, then later get in your spa, you'll need a lot more FC than if you shower just before getting into the spa. Any skin lotions, perfumes, etc worn by soakers will also require more FC.

Some FC will get used up just sitting there, but the biggest drop is the first X number of hours after you get out of the spa as the FC breaks down all the bather waste. My general rule of thumb is to get the FC to my target level of 5 before I get in (I run a CYA of 30), then add enough when I get out that the next morning I'm well above the minimum still (typically 1-3 oz of 8.25% bleach depending on wife and me or just me, time soaking, etc). I'd recommend you play around with amount needed to add after you get out so the next day when you test you're somewhere between the minimum and target FC. Do this, and your cloudy water is gone for good. :thumleft:
 
Well I'm glad I was reading this thread.......
I just assumed from everything I had read that CYA built up and didn't dissipate.... I checked mine and at week 5 it was less than 20. I topped off the tub and got it back up to 50 whoops (I was shooting for 40 will 50 hurt anything?). I didn't realize it burned off that quick in a hot tub.
 
Thanks for the response jseyfert. Tons of good and helpful information I really appreciate it. (As well as everyone else on the forum) I will have to make some adjustments according to my CYA level. You mentioned above the FC/CYA chart. Where do you find such a chart? Considering FC changes with the amount of CYA
 

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Thanks for the response jseyfert. Tons of good and helpful information I really appreciate it. (As well as everyone else on the forum) I will have to make some adjustments according to my CYA level. You mentioned above the FC/CYA chart. Where do you find such a chart? Considering FC changes with the amount of CYA

I just found it this evening under pool school CYA.

Pool School - Chlorine / CYA Chart
 
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