Saltron Mini - How often to open the cover and "let the CCs out"?

[GreenLeaf]

Thanks.

I'm now on day 5 of keeping Cl at 12+ and CCs have been interminably stubborn. I'm down today to 0.21, yesterday was 0.3, I'm losing about 0.1 per day. Saltron running 24x7 and also manually adding Cl. I "feel" more progress is made with the cover completely off and in full sun (which also means adding Cl more frequently). Is it normal to take this long?

 

[JoyfulNoise]

Thanks.

I'm now on day 5 of keeping Cl at 12+ and CCs have been interminably stubborn. I'm down today to 0.21, yesterday was 0.3, I'm losing about 0.1 per day. Saltron running 24x7 and also manually adding Cl. I "feel" more progress is made with the cover completely off and in full sun (which also means adding Cl more frequently). Is it normal to take this long?

Combined chlorine (CC) is a catch-all phrase for chlorinated organic compounds. It can represent a wide variety of different chemical compounds, some of which are detectable by testing and many others are not. As chlorine further oxidizes these compounds they can sometimes result in by products that are detectable. A more accurate term for them is “disinfection by-products” (DBP’s). There are also some CC compounds that are considered “persistent” in that when they react with chlorine they become chlorinated organic compounds and they cannot be further oxidized by chlorine. A typical “breakpoint chlorination” curve looks like this -

https://www.ixomwatercare.com/docum...lletin-breakpoint-chlorination-curve/download

Don’t mind their numbers as they get the Cl/N ratios wrong. But the shape of the curve is what’s important. As you see, you’ve probably added plenty of chlorine by now, more than enough to exceed breakpoint but what you’re measuring as CCs are probably nitrogen trichloride and some persistent trihalomethane (THM) compounds that will not go away by adding more chlorine. You’re also seeing that the CCs are going down with time and an open tub. So really what you need to do is add chlorine and aerate the tub while it is open. That will do the most to lower CC levels. However, as I said above, there are persistent CCs that will just never resolve on their own. That’s why hot tubs should be emptied regularly.

 

[GreenLeaf]

Thanks very much Matt. This forum and community is a treasure.

What I see is that if I want to be able to throw a big party, and not have to babysit the spa every 2 hours, I am going to need some kind of extra firepower. I like to over-engineer things where possible, sometimes that gets me into trouble. I'm very health conscious and want to get my water and especially the related gasses down to an absolute minimum to preserve my health.

Serious question - I know TFP is very focused on keeping things simple, pragmatic, and helping people avoid snake oil. I'm open to new technology. I get the impression that if I were to try to integrate some kind of "AOP" system into the mix as a supplemental system to chlorine, I may be able to reduce my Cl residual as well as better manage the extreme Cl load peaks when I want to have a party. There are dozens of seemingly interesting articles on AOP in scientific journals and ResearchGate. As JN mentioned, UV + O2 might be worth exploring, there seems to be a vibe on O3/UV plus MMO anodes but I am just a lay person with no real chemistry understanding... There are a couple of commercial products out there, I will refrain from mentioning them, but the typical refrain is that they have enabled users to significantly reduce their chlorine residual.

Is there any appetite for further discussion of this on TFP? If not, I totally understand, it's not part of the TFP mission. I won't bring it up again. If there is, I'd like to speak with anyone interested or who has experience with this topic or a successful installation, and try to sort the wheat from the chaff. I'd work towards building something to make my spa as close to bullet-proof as possible over the next year or two, just as TFP has helped me do with my pool which is working like a dream and regularly measures CC of 0.

 

[JoyfulNoise]

Thanks very much Matt. This forum and community is a treasure.

What I see is that if I want to be able to throw a big party, and not have to babysit the spa every 2 hours, I am going to need some kind of extra firepower. I like to over-engineer things where possible, sometimes that gets me into trouble. I'm very health conscious and want to get my water and especially the related gasses down to an absolute minimum to preserve my health.

Serious question - I know TFP is very focused on keeping things simple, pragmatic, and helping people avoid snake oil. I'm open to new technology. I get the impression that if I were to try to integrate some kind of "AOP" system into the mix as a supplemental system to chlorine, I may be able to reduce my Cl residual as well as better manage the extreme Cl load peaks when I want to have a party. There are dozens of seemingly interesting articles on AOP in scientific journals and ResearchGate (random example). As JN mentioned, UV + O2 might be worth exploring. There are a couple of commercial products out there, I will refrain from mentioning them, but the typical refrain is that they have enabled users to significantly reduce their chlorine residual.

Is there any appetite for further discussion of this on TFP? If not, I totally understand, if there is, I'd like to speak with anyone interested and try to sort the wheat from the chaff, and work towards building something to make my spa as close to bullet-proof as possible over the next year or two, just as TFP has helped me do with my pool.

The AOP systems are really a waste of money. This is a hot tub we are taking about, not a water treatment plant. The water can be simply dumped and started up fresh. I know people don’t like that response because they have some aversion to “wasting water” (they should consider how long they spend in their showers or how much water they dump on their lawns before they start glaring at the hot tub), but trying to keep tub water for more than 2 months or so is a fool’s errand in my opinion.

What I would say to anyone that really wants to tinker is this - consider finding a way to add a UV sterilizer on to the tub and connecting it ups to the system so that water can be treated after soaking but not necessarily all the time. The aim should be to destroy as much bather waste, or reduce it to simpler ammonia based compounds, BEFORE adding chlorine back into the mix. Peroxide and UV can create a very power oxidizing environment for bather waste but peroxide also reduces chlorine. So in a UV/H2O2 system, you would need to dose and treat the water and ensure that all of the peroxide is used up prior to adding back chlorine or else the chlorine will be fighting with the peroxide.

Ozone is just a bad idea for hot tubs. It’s only useful ina bromine based tub and, even then, the CD ozone generators used are childish toys. Best to just avoid them.

Of course, it’s your time and money and if you want to go ahead and spend that capital on tinkering with your tub, no one here can stop you. Your welcome to document your efforts but I don’t see it changing many minds as most people really just want to “keep it simple”.

 

[GreenLeaf]

Thanks for the wisdom Matt. FYI this tub had an Ozone generator, but it filled up with water at one point (failed valve I believe) so I just removed it.

We'll see how things pan out in the future once I start feeding the right end of the horse and get some experience with that.

 

[Mdragger88]

Thanks.

I'm now on day 5 of keeping Cl at 12+ and CCs have been interminably stubborn. I'm down today to 0.21, yesterday was 0.3, I'm losing about 0.1 per day. Saltron running 24x7 and also manually adding Cl. I "feel" more progress is made with the cover completely off and in full sun (which also means adding Cl more frequently). Is it normal to take this long?

Do yourself a favor & Use a 10 ml sample & measure by .5 increments. That is precise enough. Cc’s of .5 or less are completely acceptable in a spa that has ever had a bather. Trying to micromanage, anticipate, & completely eradicate the minuscule amount of cc’s you have will drive you crazy. Also, as was mentioned above- give the filter(s) a clean. You may also want to clean your beaker with alcohol. A dirty beaker can show Cc’s when there’s not because of residue from when you had a lot.

 

[GreenLeaf]

Thanks, done and done. I gave my filters a thorough high pressure wash out (the last time was 3 days ago), and they did have a lot of dead mozzies and other tiny insect matter in there. I'm guessing the extra matter would be a contributing factor to the Cl consumption. I'll put a mesh net across the intake so they don't get stuck in the filter vanes. What's the TFP recommended chemical/process to clean spa filters? I'll follow the TFP recommended filter cleaning process

UPDATE: I had my first "proactive not reactive" spa tonight. Noting I cleaned the filters first which might have been loading up my consumption/CCs, I started with FC7, CC0.15. After 2 hours and 4 beers - FC5.5 and CC0.08, and after 3 hours and 6 beers - FC4.5 and CC0.08. We have a winner, I believe!

 

[Methuselah]

Thanks, done and done. I gave my filters a thorough high pressure wash out (the last time was 3 days ago), and they did have a lot of dead mozzies and other tiny insect matter in there. I'm guessing the extra matter would be a contributing factor to the Cl consumption. I'll put a mesh net across the intake so they don't get stuck in the filter vanes. What's the TFP recommended chemical/process to clean spa filters? I'll follow the TFP recommended filter cleaning process

UPDATE: I had my first "proactive not reactive" spa tonight. Noting I cleaned the filters first which might have been loading up my consumption/CCs, I started with FC7, CC0.15. After 2 hours and 4 beers - FC5.5 and CC0.08, and after 3 hours and 6 beers - FC4.5 and CC0.08. We have a winner, I believe!

There's a rule of thumb bather load "formula" around here for estimating consumption of fc per bather-hour. I've never needed it, but it seems like you can come up with a very good guess just knowing what you dumped in during the above. REMEMBER slam level is ok to soak in with cya in your 30'ish range, so why not target a minimum of 10 or 12 just to make sure you never dip below minimum? It's not fc that causes itch, but cc byproducts.

A closed loop system is expensive, and according to Matt wholly unnecessary. For you though, a parastaltic (sp) pump could be rigged to a timer to do a 30 min. dose based on preceding paragraph computation. I designed one for vacation but when I switched to higher concentration bleach the float can't measure such a small amount so will have to modify circuit for level electrodes... .

Accordingly, I suppose you could pre-measure dosing in small containers and use a kitchen timer too...

Anyway just spitballing - like Matt said (and @Mdragger88), persistent cc's are inevitable, and at some point force you to dump and refill.

Matt's suggested 2 months actually sounds closer to correct than I'm normally seeing as consensus here. I made mine "limp" thru 6 months by upping CH for foaming, and adding borites for ph rise, but it really was about the 2 month mark when the water started "making demands". Matt is true treasure here on the forum, so I'm all ears when he chimes in...

Sorry so long winded, especially since you seem to now have a handle on it. I like your idea of an extra screen, just make sure it can't clog and lower flow rate - you don't want to burn out a heater element.

 

[GreenLeaf]

But it seems like you can come up with a very good guess just knowing what you dumped in during the above

I've worked that out, it's about 1.2 FC per person per hour, which translates to about 17ml of our 12.5% Cl here.

a parastaltic (sp) pump could be rigged to a timer to do a 30 min. dose based on preceding paragraph computation. I designed one for vacation but when I switched to higher concentration bleach the float can't measure such a small amount so will have to modify circuit for level electrodes... .

This is actually a brilliant idea. I could rig up an arduino circuit with an up/down button, you just adjust the number up from 0 to however many people are in the spa at the time and it can dose pro-rata.

I designed one for vacation but when I switched to higher concentration bleach the float can't measure such a small amount so will have to modify circuit for level electrodes... .

Or dilute it perhaps (unless space was the issue).

FYI, I've been working on a Raspberry Pi based solar heating controller. It uses multiple DS18B20 probes to check roof temp, solar return temp, and pool temp, turns on when the roof it hot and stays on as long as the actual return is warmer than the pool. Pump switching is entirely wireless (ie: safe) via 433mhz signal to commonly available remote control AC switchers. Still in "beta" but when it's ready for the public I'll make the source / repo public for any TFPers to have a play with, and do a PCB for it too... It runs on a Laravel LEMP stack.

Sneak peek attachment below... (don't mind the pool chart, that's actually the pool return not the pool itself, I'm still working out how to get a sensor nicely deep into the pool and not have it eaten by the pool robot)

 

[GreenLeaf]

Couple more weeks of experience and I'm getting the hang of it.

Good call on checking the filters. I found my filters, which I was cleaning only with fresh water via a hose jet, contained a lot of bug matter in the edges of the pleats. All those flying ants, and innumerable mosquitos, all ended up in the filter and what I wasn't washing out stayed there.

I DIYed up a "filter pre-filter" using some replacement leaf net mesh, PVC, and stainless bolts/wing nuts, and that now happily sits inside the filter intake and appears (based on what it's catching) to keep the Australian fauna out of the filters.

I also bought a pair of brand new filters, and some trisodium phosphate so I can "swap and go", then soak filters for a day or two.

Keeping FC above 4 seems to do the trick with CCs so far. As my FC drops down towards 3 they seem to start, but that's just an anecdotal vibe at this point.

PH loves to wander up past 7.6 especially if I add Cl to "pre-dose". Right now I'm getting the hang of the feeling of adding acid and feeling TA pushing back harder the lower I try to push it, moreso now I just accidentally bumped TA today from 50 to 70 and was trying to get PH down to ~7.3 and have it stay put. Read chem geek's "TA - Further Reading", I like the shock absorber analogy and this graph showing where bicarbonate and borate buffers "push from" (if I understand it correctly).

I'd like to explore borates for the reason of trying to ensure my PH is ideal for skin/eyes/irritation/spa experience. I have some boric acid on the way. I've read the "Borates - Why and How" and "Borates - Further Reading" articles on TFP. If I understand things correctly, it doesn't evaporate so shouldn't be present in spa steam , it only absorbs very slowly through the skin, and is an essential nutrient that might provide me with numerous health benefits including increased testosterone. I should just avoid drinking multi-litre quantities of the spa water, right?

If I wanted to dial in the "ideal PH" to avoid skin/eye irritation, what final TA/Bor/PH would you aim for in a spa?

 

[Mdragger88]

There’s no perfect ph - mid 7’s is a good target for swimmer comfort but anywhere in the 7’s is ok. Your ph probably won’t ever stay at 7.3, my tub consistently hovers around 7.8 for some time before making its way to 8.0. It doesn’t bother my skin at all nor my sensitive hubby’s skin.
Getting ta down to around 50 generally helps alot with ph rise frequency.
I am not understanding how your ta went from 50 up to 70 when you added acid.
Ph & TA are “married” chemically.
When you increase one with a chem (baking soda, borax, washing soda) you also increase the other in some way.
Did you add something besides acid?

When you use acid you lower them both in some way.
The only way to change one without the other is by aeration which increases ph without raising ta.

Once ta is around 50, adding borates to 50ppm can be a helping hand in slowing ph rise. I don’t know about the health benefits you mentioned but you should avoid drinking the water in large quantities. Same goes for pets. Inadvertently Drinking spa water isn’t really as commonplace as with a pool so not a big concern for most unless your dog thinks it’s their water bowl.
But please understand that in a spa, even with the lower ta & addition of borates,
ph will still rise & you will still need to add acid to keep it in the 7’s , although it may not be as frequently. Chasing the “perfect ph” is a fool’s errand & will drive you nuts.
When it rises to 8 lower it back down to the mid 7’s & carry on enjoying your tub.

 

[GreenLeaf]

Sorry for not being clear! TA increase today was from me adding bicarb. I tested FC/CC, PH, CH, TA, and the TA test was "half way between green and red" after 4 drops, my interpretation was that meant a TA of about 45. I figured it couldn't hurt to bring it up a bit more to 60 or 70 so I added around 35g of bicarb, but now see that really does make the "spring" in the buffer a lot stronger. It took quite a bit of acid to bring PH down to 7.3. I used the acid demand test each time, usually just one drop, see where it should land, and add some acid. I conclude my 32% acid must be weaker than expected, as the movement that the Taylor's little handbook says should happen requires about 150% of the amount of acid they say it should.

I think I am beginning to see now why the recommendation is to leave TA at about 50 in a spa for a good mix of overall PH swing control, and a minimal amount of upwards pressure from the bicarbonate buffer, considering you'll get so much upwards drift from the aeration you don't want to make work for yourself.

Ok, I won't fret about PH, just try to keep it in the mid 7s.

Thanks

 

[Mdragger88]

Thanks for clarifying.
You don’t call the ta test until there is no further change- you can’t accurately interpret the back & forth from green to red as this can happen for multiple drops.
Trying to do so just confuses things.
No need for baking soda unless you were truly at 40.
As you lower ph, ta will fall thus stabilizing the ph rise so no harm done , just unnecessary adjustment that’s all.
Happy hot tubbing

 

[Methuselah]

Sorry for not being clear! TA increase today was from me adding bicarb. I tested FC/CC, PH, CH, TA, and the TA test was "half way between green and red" after 4 drops, my interpretation was that meant a TA of about 45. I figured it couldn't hurt to bring it up a bit more to 60 or 70 so I added around 35g of bicarb, but now see that really does make the "spring" in the buffer a lot stronger. It took quite a bit of acid to bring PH down to 7.3. I used the acid demand test each time, usually just one drop, see where it should land, and add some acid. I conclude my 32% acid must be weaker than expected, as the movement that the Taylor's little handbook says should happen requires about 150% of the amount of acid they say it should.

I think I am beginning to see now why the recommendation is to leave TA at about 50 in a spa for a good mix of overall PH swing control, and a minimal amount of upwards pressure from the bicarbonate buffer, considering you'll get so much upwards drift from the aeration you don't want to make work for yourself.

Ok, I won't fret about PH, just try to keep it in the mid 7s.

Thanks

I just re-read the entire thread. You still seem to have a phobia of getting in with fc closer to SLAM levels. Just know your observation about it being best to not letting cc's rise in the first place is best practice. If fc drops below minimum you know how that plays out...

The screen is interesting, hope it doesn't clog!

I saw you asked (and were answered) on leaving the top off while working on reducing cc. This after a bather load of 8 people over the course of a day. It was a fight you seem to barely have won (with a lot of fuss). Yes, the bugs weighed in, and it took time to realize they left behind matter in the filter(s).

On this matter I'm going to compare when my water "went south" to yours. Our bather load was 5 days a week, 2 people, 15 minutes. In two months that's 150 person hours. Yours was 8 people, 8 hours. In 2 to 3 days at that rate if equivalent you would expect problems. Note between our use we had cover off, weekly filter cleaning, and run time on filtration likely doing us more good than your situation.

Notable is that you just hit Matt's dump the watter recommendation in 2 or three days.

We all strive for the simplest solution that stretches time between fills, while maintaining healthy chemistry. When that fails it's time to consider dumping and starting over.

I'd recommend laser focus on staying away from the minimum fc side, shooting for 40-50 TA (thereafter considering borites if you must, but, why if 3 parties force your hand), watching splah out because you will drop CYA with water loss, and keeping the filter clean. The filter cycles are adjustable too...

Frankly, I've seldom seen mention of bather load as high as yours, but I think that's to be expected on the cabin rentals we've done, and I've seen several posts where after a rental they dump and refill force of habit. Just saying.

Well, I suspect everything's been said at this point, I hope you keep us posted on how it goes. Ever figure out why your fill water is yellow, let us know...

Best
Methuselah

 

[GreenLeaf]

Welp, my heater gave out today, when the element terminals are connected it trips the GFCI. I think that took all of about 3 weeks... no idea how old it was as I bought the spa second hand. Tube has manufacturing date of 2005, and uses an incoloy element. When I did this first ever balance, I messed up the weighing of the salt and ended up with around 3000ppm (pool store measured 2700 then 3050), rather than what I was aiming for (2000ppm). As documented, I have been very vigilant with maintaining PH within the 7.3 to 7.8 range. CH is 120, TA 55.

Does high FC aggravate corrosion or is it mainly salt ppm + ph? I also saw on another forum some discussion about needing to avoid the heater becoming a sacrificial anode...

Currently searching for a suitable replacement, one mob that I reached out to to confirm the right part told me no heater made will withstand salt, salt use is not covered by warranty, they advise against salt chlorination. Fair enough. The part they have is 304SS tube and titanium sheath element. While you can get a titanium tube for Balboa packs, it doesn't look like you can for Gecko.

 

[GreenLeaf]

@RDspaguy your insightful personal necdotes on ozonators over in this thread is very interesting

I've got a closed portable tub with a Saltron Mini. It's usually closed for a few days at a time. I have it FC and relatively PH stable. It handles "me + 1" situations AOK but I'm trying to make it survive "+ 10" situations. Your story about kids and 3 dogs made me laugh.

My ozonator died a while back (check valve, water ingress). I didn't note the model number but it looked like a MCD50. There's no 24/7 circulation but the Gecko MC-MP manual says I can set 2 x 12 hour filter cycles. The ozonator ran whenever pump1 ran, so I assume I can fudge 24/7 ozone when I need to.

Your post makes me think perhaps I should put an Ozonator back in the mix and run 24 hour filter during parties and the day after.

Can I ask you or anyone who might know...

1. Why do you always land back at 0.5FC? Does the ozone likes to eat up "all but the last bit" of FC?
2. What type of replacement ozone system would you recommend?
3. Saltron is on a timer, running 15 minutes every hour which keeps my FC stable. How hard will the ozone hit my FC during normal operation (my power meter says the heater/pump1 kicks in for 10 minutes every 2 hours).
4. Can ozone break up persistent CCs?

I've read the TFP advice on Ozone systems in spas, the only negative would seem to be chlorine consumption but since I have the Saltron there's no real additional cost or hassle other than more cell use.

Worth considering? A lot less hassle than some of the other crazy ideas I've suggested...

 

[Methuselah]

1. Why do you always land back at 0.5FC?
2. Can ozone break up persistent CCs?

A lot less hassle than some of the other crazy ideas I've suggested...

1. Because it's an indication you sanitation has failed and your water is trying to kill you
2. Most of the time it's too late for that without going to a LOT of trouble because #1 is a really bad thing

Bottom line is the closer you get to a situation where your CC is rising and "doesn't want to come down", the more likely you've hit a point where it's easier to dump the water and start over.

Maybe best answer is adjust you chlorine output upwards during your party until you find the sweet spot where it maintains SLAM level during the party, and afterwards turning it back down and see if that resolves rising CC.

Just my $.02.

 

[Mdragger88]

Saltron is on a timer, running 15 minutes every hour which keeps my FC stable

This seems like alot of micromanagement & alot of off/on for the unit.
I do 1 hr 2-4 times per day (equally spaced intervals) depending upon usage/season. In the summer we use the tub less so a total of 2 hrs/day is plenty, in the shoulder seasons & winter we use it more (often twice a day) so 4 hrs total works well.
My tub is only 200 gal- so you may need to increase those amounts/intervals.
A little extra fc is fine but too little is a problem fast. Always shore your bets & you won’t be playing catch up. For parties (10+ like u mentioned) manually dosing before, during & after is a must- the swg just takes too long & will leave you playing catch up. Don’t fret over having fc at or near slam level before the party- as soon as dirty bodies hit the water the fc will drop quickly. Test periodically to ensure you stay above minimum. The swg can help ensure this but it likely won’t be able to do all the work in that situation.
Think of it like this- the swg is like an iv drip of fc that can only dole out so much per minute (slow & steady) but dosing with liquid chlorine is akin to gulping a large glass of fluid all at once- instant results that are fast enough to compensate for the large amount of batherwaste right then.

 

[RDspaguy]

Your post makes me think perhaps I should put an Ozonator back in the mix and run 24 hour filter during parties and the day after.

I normally would not recommend such long cycles on the main pump for numerous reasons, but as a once-in-a-while thing it would be fine. Frankly, I'm not sure it's worth the expense under those circumstances but it's your money, if you want to try it out go for it. Most systems turn off the ozone if jets are on or for 30 minutes any time a button is pushed, so you'll have trouble running it during use anyway.

Why do you always land back at 0.5FC? Does the ozone likes to eat up "all but the last bit" of FC?

Now you're asking science questions to a repair man. I don't know why the depletion slows as the ppm drops or nearly stops at 0.5, I just know what I find in my water and read online. Maybe it's due to less than 100% exposure to the ozone. Ozone has been used for a long time in other industries, such as municipal water treatment, and there's all kinds of independent studies that have been done. If you live in a city, you might drink ozonated water. It's how they remove the chlorine they used to sanitize in many drinking water facilities.

What type of replacement ozone system would you recommend?

Ozone output must be compatible with the injection system or problems can arise. I recommend whatever it started with, as that's what the system is designed for.

How hard will the ozone hit my FC during normal operation

Tubs that use the main pump for ozone injection are impossible to know flow rates, and therefore exposure turnover rates, without installing an inline flow meter. Most are not very efficient compared to a 24/7 and are mostly there as a selling point since major brands with 24/7 systems make a big deal of it. How it will effect yours I do not know, but most people with tubs like this never notice it fail.

Can ozone break up persistent CCs?

That's what it does, but it requires exposure, as discussed above. Likely ineffective in that tub. I would think your saltron would also oxidize cc, at least inline cells seem to, so persistent cc may be an indicator of biofilm or cover contamination.

Because it's an indication you sanitation has failed and your water is trying to kill you

The water gets sanitized by chlorine, and the resulting cc and most of the extra fc are oxidized away with the cover on. Until you open the cover to contaminants you don't need a residual. All you have to do is use ENOUGH chlorine. Fail to sanitize and the ozone will be hard-pressed to save it, even in a 24/7 system. This, of course, does not apply to commercial/public spas, which are required to maintain a residual and therefore do not typically use ozone or uv. FWIW, most portable spas do not meet public safety regulations either, which is why you won't see them at hotels and such. So before anybody starts crying about regulations, know that this whole thing does not meet, nor is it required to meet, regulations for public pools.

 

[GreenLeaf]

1. Because it's an indication you sanitation has failed and your water is trying to kill you
2. Most of the time it's too late for that without going to a LOT of trouble because #1 is a really bad thing

Bottom line is the closer you get to a situation where your CC is rising and "doesn't want to come down", the more likely you've hit a point where it's easier to dump the water and start over.

Maybe best answer is adjust you chlorine output upwards during your party until you find the sweet spot where it maintains SLAM level during the party, and afterwards turning it back down and see if that resolves rising CC.

Just my $.02.

You have been so helpful Methuselah! I'm sorry, my wording wasn't clear. When I said "you" I meant @RDspaguy, not "in general". Maybe I should have posted over in that thread.

In Post #5 by @RDspaguy in New spa- Why bother with Dichlor? Why not CYA and bleach he seems to suggest that if he hits 0FC, without an ozonator, he can top up to 10 he might land at "9 or 2" the next day or might land at 0 (if there were a few extra dogs).

If I understand his post correctly, he's suggesting that no matter what extra FC he throws at it after the party he will land at 0.5 if he is using an ozonator. I assume when he says "But with good ozone on 24/7 I can hit it hard after use" he means "add lots of chlorine", and not "hit it hard with the ozonator".

Maybe best answer is adjust you chlorine output upwards during your party until you find the sweet spot where it maintains SLAM level during the party, and afterwards turning it back down and see if that resolves rising CC.

Yep, understand this 100% and this is where I'm at, thanks to all the help of the wonderful TFPers in this thread. I have my spa now FC and PH stable, just leaving FC at 5, and if I have say 4 people over I'll top up to ~10 and let it run back down to 5.

I just thought @RDspaguy's comments on Ozonator use might be helpful in terms of me adding more firepower for situations that get out of my control (Eg: a dozen people jump in while I'm doing something else for 2 hours).

This seems like alot of micromanagement & alot of off/on for the unit.

I'd rather have my FC stable so whenever I test during the day or jump in I know my FC is going to be 5, and not at the start or end of a Saltron cycle. I don't think the extra on/off would hurt the unit but I'll write to Solaxx and ask and if they say it will reduce the life of the unit I'll cut it right back.

Don’t fret over having fc at or near slam level before the party

Yep, I got this 100%. You all have been really great at helping me understand the whole scenario and I think I have your advice implemented effectively:

• Saltron Mini
• TA40, CYA30, PH7.4, CH120, FC5, Salt 2000ppm
• Be ok with letting FC drop to 3 but no less (Me + 1 for 2 hours)
• Anything more than me + 1 bring FC to 10 and don't let it drop below 5
• Open cover to let the CC's out a few minutes a day