YIKES - green tub.

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dunginhawk

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Jul 10, 2018
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Ok. Havent used the hot tub in a week or so, and I wake up to a green tub. NO FC......
As soon as I saw it I knew... CYA was 0.... I dont know why, and maybe this is normal, but my CYA dissipates fairly quickly.
Is that fairly common? I had a CYA of 40 not long ago when I filled the tub... Is it fairly common to have to check CYA weekly and top it off?
I know it does slowly dissipate, but I didnt think you would go from 40 to 0 in the matter of a few weeks.

so I am slamming now, and we will see what happens.
 
How quickly does your free chlorine go away? If you add chlorine and within 15 minutes it is gone you may have a bacteria problem. If it is only 450 gallons I would just empty and refill.
 
well, it was green... so ive added a lot of bleach... im stable now... im holding it about 10+... if it dips below I add a few more ounces to bounce it back up.
Ive certainly thought about a drain refill, and depending on how the next hour or two goes that may be what I do.

So I havent checked the tub in a week like I said and the FC is being made by the SWG certainly enough to maintain my FC optimal level, but for whatever reason my CYA seems to drop quicker than I think other tubs for some reason. All the numbers are within spec but CYA seems to drop I guess it would average about 10 ppm per week. Once it got too low the swg couldnt keep up and bam. Green water.
So Ill get this all sorted out , get my clean tub going again then try to figure out why the CYA isnt maintained like it should be.
 
Ok... so FC is being used, but still doing well. hour or so after slamming it was about 5-7 again so I popped it back up over 10.
Tub is still not clear... Not sure how long it should take to clear up. Assuming its not something that will happen in 2 hours :) Truly does almost seem easier to just drain and refill.
Wondering if I do that should I do an ahhsome again, considering i did it just a month ago.
 
So rather than wait for some advice or recommendations I just went ahead and did ahhsome to be safe... Glad I did... while It wasnt bad, it was still enough that Im glad I did it. Its now drained, and about rinsed, wiped down, rinsed, and drained again... Now im filling it up again.
This time im going to do salt first, instead of balance PH. Last time I did PH first and it was altered by the addition of salt later.
 
my CYA dissipates fairly quickly.
Is that fairly common?
Click to expand...

It is on my tub. I use trichlor as my acid to counter act this. dichlor works too, but i found I had better water quality using pucks (I bust them up into smaller chunks) because of the slower dissolve rate. I use a dispenser dialed back for slow action.

I estimate that CYA drops one point per day on average with my spa.
I also shoot for a higher CYA target than the 30 recomended here on tfp. I shoot for 50-80.

Hope this helps
 

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No. it is covered. 99.9% of the time anyway.. perhaps my chemistry is wrong (but I read the chlorine guide 100x) but the stats certainly dont lie. My swg is working great, and when my CYA is good my FC is good (with no additional bleach needed). for whatever reason (and perhaps its normal) my CYA seems to drop 1ppm per day or maybe a bit more.
My tub was refilled on March 16. I was at 40CYA.
Sometime in the last week it was essentially zero (or close to).
So more like 2ppm per day.
Not a huge deal if i have to manage it with that expectation, But I didnt think it was something that dropped that quickly.
 
What temperature do you keep your tub water at when not in use (standby temperature)?

Higher temperature water will deplete CYA faster but losing 30ppm CYA in a covered tub is NOT normal. You said you did an Ahh-some purge and got some biofilms and slime out. That is possibly a cause of your problem as some bacteria will consume CYA during cellular respiration (though that usually forms ammonia which is another problem). It also sounds like your salt cell was not generating adequate FC levels.

FC loss in a hot tub is not affected as much by CYA as it is in an outdoor pool UNLESS the tub is uncovered and exposed to UV. In a hot tub, the salt cell doesn’t work any better with higher CYA. So my guess is your salt cell is not producing enough FC. If it’s not on it’s highest setting already, I’d turn up the output control.
 
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So it doesnt have settings. its internal and dependent on the salinity. 2600 is base recommendation. I run it about 2800ppm. It keeps up with 1 bather per day load just fine. Im fairly certain it is operating ok.
Now you could be on to something with the biofilm deal. I did just do a refill (3 weeks ago), and after the fill i was still cleaning quite a bit of gunk out for the first few days. I am doubtful I tested the CYA after that too, so it could have been on the way down or depressed at that point.
Ill keep a closer eye on it this time around.
So this refill (its at 75 degrees now) I seem to be getting a LOT less biofilm out after the refill. There will always be some, unless you drain, rinse, refill, heat, drain rinse etc. . Ill test all chemicals weekly or more over the first month of this fill.

PS I keep my tub at 104, constant. I never know when I want to get in, so I just leave it there all the time. Wish I had automation capabilities to warm it up from say 98 to 104 an hour before I got in, but i dont, and the button layout is too archaic to do it manually all the time. Id love to pull that panel and install a new one but not even sure if thats possible.
 
At 104F, you’re definitely going to see a higher extinction rate for CYA than a tub kept at a more normal standby temperature of 97F. For every 13F increase in temperature, you typically get a doubling of reaction rates. The published CYA extinction rates are for water that is around 75-80F and so you can expect your tub to lose CYA at a much faster rate.

Also, keeping the tub at 104F puts a huge strain on the heater. I realize it’s not convenient, but you’re wasting a lot of energy the way you’re running it. Oh, and 104F is considered to be an optimal temperature for mesophiles (bacteria and fungi) to grow in. So, if your FC fails, your water temperature is about as perfect as it can be the rapid bacterial growth (colony forming unit, or CFU, doubling every 45-60 minutes).
 
Well that would be why in just a few days it went so badly haha... Ill have to keep a much closer eye on it.
Is there anything out there that I can buy to replace my current panel with a smart one? the smarter the better. Really id just love something easier. Like a touch screen or even a phone app. I dont want to leave it at 104 all the time, but one of the downsides to buying my tub at a great price was its oldish panel. Id gladly pay $$$ to swap it out.

Thank you for the info. Ill happily take it all in to consideration.
 
I think I see what your problem is - the CSS5-1 Prozone system.


Ozone and chlorine destroy one another as they are both powerful oxidizers. According to that link, the Dr. Wellness spas use a combination of UV generated ozone (not a very efficient method) and a weak SWG to “sanitize” the water. By their own admission, the chlorine output of the salt cell is very low so as to create almost undetectable amounts of chlorine. They justify this on the usual bad theory that ozone allows you to use less chlorine and thus the water is “safer”. It’s the same pseudoscience nonsense that TFP deals with all the time on residential pools - “Hey, add this gizmo and you’ll cut your chlorine use in half!!”

So here’s what I think is happening - your ozone generator is basically destroying any FC it generates and that leaves the water with bacteria that can flourish as there’s not enough ozone to act as a sanitizer (and it technically isn’t a sanitizer under EPA rules). As well, the ozone + high operating temps is destroying your CYA at a higher rate. So the net effect is that, over time and as the water sits unused, the tub becomes unsanitary and bacteria can grow.

I suppose the “good news” is that most tub ozonators are cheaply built and die within a year or so of use. The down side is that the SWG is probably too weak to keep up the FC all on its own. So eventually your CYA loss will go away but your FC generation will be weak.

Try turning off the ozone generator to see if it helps. The bulb that generates the ozone should be accessible and is likely fitted with a plug that lets you pull the power to it.
 
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WHen I have time to get in the tub and turn off the ozone I will try that for sure. I am in the process this morning of getting the tub to the right balance again.
So I think the prozone is on its own power switch.. the entire unit... I presume the unit is just basically a bulb with a pass through of water through it. I assume I can just power off the entire unit and still be pumping water through the unit, just without the light...

Also I lowered the tub temp to 100 degrees on the high end.

Ive also reached out to the company to see if I can replace my panel so I can regulate my temperature more easily.
thanks
 
The ozone generator is an air source / Venturi injector. In other words, the bulb is enclosed in a tube that has atmospheric air in it and a Venturi tube sucks the air + generated ozone into the plumbing. As I understand it from that brochure, the ozone lamp and SWG are powered up as one unit so, I think, if you power off the entire prozone unit you’ll lose the SWG as well. That’s why I suggested merely pulling the plug on the UV lamp if it is accessible. But, you could power down the entire prozone unit and just try to keep the tub balanced using the dichlor/bleach method.
 

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