Starting up a hot tub

[dogsbody]

Here we are, a month later, and I've been getting fairly comfortable with keeping the water balanced (fixing the leaks - both serious and non-serious - made rather a big difference). At the moment, pH is 7.4 , TA 70 , and CYA 50 , and is stable from day to day. Now I'm trying to get a handle on FC. After trying for a minimum target of 1-2 ppm, I went for 7 ppm (per the calculator with liquid bleach) in order to get it into a range where I might get consistently nonzero readings, and it didn't help much.

Our usage is light - an average of 1 person-hour per day, when the sun is either low or down - and the rest of the time the cover is on, so UV isn't a significant factor (at this time of year, anyway). So I'm thinking that there must be a base organic load in the water that's just eating up the FC, and my failure to shock the tub to date is why. Am I on the right track?

 

[mas985]

Water temperature is another factor that can increase the CL decay.

Breakdown of Bleach Over Time by Storage Temp - Further Reading

www.troublefreepool.com

 

[dogsbody]

Sure, but that doesn't actually answer my question. We're running it at 102-103F. And the (pool) bleach I'm using is new and has been kept at room temperature until a couple of days ago, when I moved it outside (because it's warm at the moment). If it freezes once the ambient temp drops again it'll come back in.

 

[mas985]

I was referring the water temperature in the spa and not the store temperature although that does matter too. When the water temperature of the spa increases, the decay of chlorine also increases just not as much as with the higher concentrations in the bottles. Also higher water temperatures also make the CL more reactive with organics so I would expect FC levels to drop faster in a heated spa than a non-heated spa.

Are you dosing after every use?

Also, biofilms can use up chlorine.

When was the last time you cleaned the spa (e.g. ahh-some)?

 

[dogsbody]

"No" and "Never". As I said, I've just spent the last month getting my legs under me in terms of water stability, and now it's Cl's turn. I'm not interested in draining+refilling before (probably early) spring, so I'm hoping that a good regimen of shock and regular dosing will put it at a happy level, and that's the guidance I'm looking for.

 

[mas985]

You might want to have a read through this:

Hot Tub Basics - Further Reading

www.troublefreepool.com

 

[dogsbody]

Once again, doesn't address the actual question, which is about Cl usage and levels. I can do without the tsk-tsk regarding whether we used Ah-Some before filling it; the weather is not friendly to a refill at present, and that'll happen in a few months. And I don't need a lesson in making a pad for it (I designed the supports to set it into our deck) and don't need to call an electrician (I'm an EE and not bad with that stuff) or be told to get a test kit (as you can see, I'm set for getting those readings. Which leaves nothing in that article regarding Cl, which is what my question was about.

 

[mas985]

Our usage is light - an average of 1 person-hour per day, when the sun is either low or down - and the rest of the time the cover is on, so UV isn't a significant factor (at this time of year, anyway).

This is why I mentioned that water temperature can also increase FC usage.

So I'm thinking that there must be a base organic load in the water that's just eating up the FC

This is why I mentioned that biofilm can also be factor in FC usage.

, and my failure to shock the tub to date is why. Am I on the right track?

We don't "shock" on this forum, we SLAM (Shock Level And Maintain). It is much more effective than a simple shock:

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

Try a SLAM and see if you can keep the FC levels up to SLAM levels for at least 24hrs.

But it may not completely solve your issues. A SLAM doesn't remove biofilm very well if you can't brush all of the area that may contain biofilm (i.e. inside plumbing). So a deep cleaning may still be necessary to reduce FC usage.

Are you running with any CYA in the water:

CYA Chlorine Relationship - Further Reading

www.troublefreepool.com

 

[dogsbody]

We don't "shock" on this forum, we SLAM (Shock Level And Maintain). It is much more effective than a simple shock:

I think I need to file that under "what-ever", because SLAM (as you indicate) is a superset of shock, which means you shock.

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

Try a SLAM and see if you can keep the FC levels up to SLAM levels for at least 24hrs.

Okay, I'll give that a read and a go and see how things behave.

But it may not completely solve your issues. A SLAM doesn't remove biofilm very well if you can't brush all of the area that may contain biofilm (i.e. inside plumbing). So a deep cleaning may still be necessary to reduce FC usage.

Noted.

Are you running with any CYA in the water:

If you read my initial post today:

"At the moment, pH is 7.4 , TA 70 , and CYA 50"

 

[mas985]

I think I need to file that under "what-ever", because SLAM (as you indicate) is a superset of shock, which means you shock.

There is a distinct difference between SLAM and shock. Shock is generally used as a one and done treatment where as SLAM is a process and may require several large doses of FC over an extended period of time.

"At the moment, pH is 7.4 , TA 70 , and CYA 50"

Missed the CYA. But for that level of CYA, you need a SLAM FC level of 20 ppm for at least 24 hrs. If you are keeping the sun off the water and when everything is dead and gone, the FC level should hold for several hours. However, if it keeps dropping, you may need to keep it at SLAM levels for longer.

 

[Mdragger88]

If you’re noticing persistent cc’s that’s another sign you need to slam.
*note - when doing the slam process in a spa you may not achieve passing the
Overnight Chlorine Loss Test by 1ppm or less since its quite a different environment from a pool but the overnight losses shouldn’t be substantial.
The cc test & the water condition along with tracking the daily fc losses will need to guide you.
You haven’t filled out your signature or mentioned whether your tub is equipped with a uv or ozone system. Both of those can also create increased fc losses as they oxidize chlorine.
If you’re not able to purge/refill at this time but suspect biofilms are contributing to your fc demand the Ahhsome people also have a weekly additive that helps eliminate biofilm buildup called aqua clarity. It is also marketed in some markets pre diluted as hot tub serum. Both of which can be used in larger doses to actually purge the tub when the time comes.
If you get a noticeable amount of detritus from the weekly treatment be sure to clean your filter(s)

 

[dogsbody]

Thanks. No UV. There is an ozone system, but I don't know whether it's working - when I got the tub the O3 generator's fuse was blown, possible cause the air inlet tube being jammed into the foam sprayed onto the outside of the tub. I corrected that problem and replaced the fuse, but have been too busy with other (more pressing) stuff to follow up and see whether the fuse has held; a quick check of the circuit didn't reveal any other conspicuous cause of the failure. Obviously I can just unplug it to remove it as a variable.

 

[Newdude]

I think I need to file that under "what-ever",

If you read my initial post

Please refrain from being rude. People won't want to attempt to help you, if you're even allowed to stay here.

But anyone trying to help you, is trying to help you. You don't have to agree, or even like the advice, but please respect that it was well intended.

 

[Newdude]

Our usage is light - an average of 1 person-hour per day,

Thats insane bather load, equivalent to *80* people in my 34k pool for an hour a day. And in the pool they are cooling down and not being simmered into people soup. Yes is alot less use than a hotel spa, but still.

Hot tubs will consume FC and I wish I understood how gross we as people are when I had my hot tub. I was forever worried I was going to melt my skin off when the tub kept asking for more chlorine.

My sweat, exfoliated skin, residual soap, shampoo, laundry sauces, etc were chewing through the FC i was adding, and for a good amount of time after use.

the weather is not friendly to a refill at present, and that'll happen in a few months.

Unfortunately the hot tub doesn't wait for a convenient time. The water needs to be changed every 3 to 6 months, maybe considerably less depending on use, how many residuals you bring into the tub, or poor upkeep.

Once the water is past a certain point, it may not be recoverable, or the expense and effort you need to recover it may not be worth it, even mid winter.

it seems miserable but doesn't need to be. I drain my pool a foot a couple times each winter and would use the same submersible pump to drain the hot tub. My hands get a little wet rolling up the hoses afterwards but that's it. If it bothered me I could wear gloves.

But back to basics. If you're having (seemingly) unnecessary FC loss,
Overnight Chlorine Loss Test. You can run this test pretty much anytime in a covered spa.

If you dont hold FC, then SLAM Process. I personally wouldn't continue beyond a day or two if the hot tub didn't respond to slam quickly. That would be my sign it was time to dump the water.

 

[dogsbody]

Thats insane bather load,

That seems to me to be an over-the-top statement. One person for an hour, once a day (or two people for 1/2 an hour, once a day) cannot reasonably be considered "insane" by any measure. That's about the lowest practical limit I can imagine, regardless of your load-comparison to a full-sized pool. What do you consider "sane", or "light"? Because my view of it is that much lower than that, and you have little reason to buy one, let alone pay for the power to heat it, the chemicals, or the effort involved. What would you call "reasonable average" usage? Five person-minutes/day?

 

[Newdude]

One person for an hour, once a day (or two people for 1/2 an hour, once a day) cannot reasonably be considered "insane" by any measure.

It's effectively a bath tub that you arent actively trying to soap up, but still do to an extent. Imagine keeping your bath water for 3 to 6 months ?

A hot tubs bather load, for sanitizing and oxidizing purposes, is insane because 1 person being simmered in 425 gallons creates alot of residual waste. So does whatever leftover soaps are still in their freshly cleaned suits.

What would you call "reasonable average" usage? Five person-minutes/day?

The point was a ton of crud comes off you and requires lots of FC, not that you were using the tub too much.

Over time you'll get a good feel for your specific normal loss, and time to dump and start over loss.

 

[dogsbody]

Please refrain from being rude.

It's unfortunate that you see it as such, because that certainly wasn't the intent - I'm here for help (and to offer some as well in my areas of expertise), not a bunfight. But my "what-ever" response needs to be considered properly and in context. You folks with long lists of hardware in your sigs and 20,000-40,000 postings under your belts are clearly very steeped in this subject, culture, and vocabulary - and that's the part you have to watch. I'm involved in lots of things that have their own jargons, and one of them alone (computer/electronic hardware) has enough abbreviations and acronyms that are bewildering to outsiders to last five lifetimes - I could offer an example of an abbreviation that contains an acronym that in turn contains another abbreviation. So we all have to be conscious of the risk of sounding silly to "civilians", regardless of how much sense it makes to us, and in context.

So when my response is "what-ever" to someone who says "Oh, we don't SHOCK around here, we SLAM instead", and I respond with "SLAM? What's that?", and the answer is "SHOCK Level And Maintain", all I'm doing is pointing out that your vocabulary may be a little hair-splitty for someone who hasn't drunk the pool water. No disrespect intended, just a little sanity check.

 

[dogsbody]

It's effectively a bath tub that you arent actively trying to soap up, but still do to an extent. Imagine keeping your bath water for 3 to 6 months ?

A hot tubs bather load, for sanitizing and oxidizing purposes, is insane because 1 person being simmered in 425 gallons creates alot of residual waste. So does whatever leftover soaps are still in their freshly cleaned suits.

The point was a ton of crud comes off you and requires lots of FC, not that you were using the tub too much.

Over time you'll get a good feel for your specific normal loss, and time to dump and start over loss.

I get all that, but you dodged the question. If you can't offer your definition of "sane" hot tub use, it doesn't make a lot of sense to characterize ours as "insane".

 

[Newdude]

all I'm doing is pointing out that your vocabulary may be a little hair-splitty for someone who hasn't drunk the pool water.

Ok GREAT. And apologies for my misinterpretations.

Shocking is when chlorine is added once without monitoring to see if more is needed. The Shock-level-and-maintain monitors the loss, continuing until there is no excess loss to prove the undesirables are gone. Whether it's algae or bather waste, it needs to be entirely irradiated or it will continue to consume excess chlorine. In the case of algae, exponentially so.

If you can't offer your definition of "sane" hot tub use

Not use, sanitation. One person in a 425 gallon hot tub is the same as 80 people in my 34k gallon pool.....

***when we are talking about FC consumption and filtering.

Imagine if I threw a raging party everytime we used the pool. That's what I'd need to do to blow through 7 ppm (?) per use in my pool. From a maintaining perspective, hot tub bather load is insane, compared to a pool.

The hot tub will require alot more attention per bather hour. The same bather makes up to 80x the dent, depending on which one he hops in. That, to me is insane.

 

[dogsbody]

So does whatever leftover soaps are still in their freshly cleaned suits.

"Suits"? We don't need no steenkin' suits. We live out in the forest. This sign is at the entry to our driveway:

Which is worse?

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