New Hot Tub with Bromine Sanitization - Initial Setup Questions and Tips

[sweetgerald]

Hi. New to hot tubs, but a 2-year pool owner following the methods outlined here for pool care (successfully, I might add ). Looking for some advice about hot tub startup/what to expect. Never had a hot tub. Never had a family member or close friend with one either, to go off of.

Dealer-installed new 325 gallon PDC Spas Catalina hot tub yesterday. Dealer includes (i.e. we pay for, lol) with purchase all their recommended "startup" chemicals, for better or worse (assortment of bromine tablets, pH up/down, TA up/down, sodium bromide, "activate granular" (is that MPS?) and "calcium booster."

325 gallon acrylic spa with ozone system as part of filtration (when main 2-speed pump is on low speed, ozone system is on, from what I gather)
Bromine tablet feeder tube installed in filter chamber
Fill water at 5pm - pH 7.2 | TA 10 | CH 25 | some presence of chlorine | 60 degrees
TF100 Pro test kit, brand new for the season
Dealer installed and showed me how to set the pump speeds, heat settings, filter cycles and briefly talked about chemicals. He didn't seem to believe in the significance of balancing CH and TA, and just said that sanitizer is king and pH matters only a little. Funny, considering they have a bundle of chemicals "included, lol" that would be used to balance those things. I figured I'd be on my own to do my water the right way anyway. The only thing he said about testing is "let us test your water once in a while, to protect you on warranty claims," but doesn't believe in 2/3 of the water chemistry.

I intended from the beginning to follow the sticky thread from this forum How do I use Bromine in my spa (or pool)? In doing so, made my first addition of a packet of 2oz Sodium Bromide (supplied by dealer) - about only 1.625oz was called for based on volume, but I inadvertently added the whole packet, so an extra 3/8oz. Hopefully not a problem. Next, slowly started adding calcium to get nearer to 100. Intended on doing this in doses because the provided chemical from dealer does not list the working ingredients anywhere I can find Sirona Calcium Booster, so I don't want to overdo it (it says 1oz would raise CH by 7ppm in 500 gallons, so by my math about 10ppm in 325 gallons - I don't know what that corresponds to in Pool Math - never had to add calcium in my vinyl pool). Over the evening I added 6oz of that. Added 3.1oz baking soda, per Pool Math, to raise TA. Tested a couple times as the hot tub came up to temp, dosing calcium booster twice. Also filled up my feeder tube with the bromine tabs and only left the minimum flow adjuster open. I can always open it more. I'm not yet sure how the ozone/bromide reserve/bromine tablet relationship shakes out, but I assume the ozone, when running, will oxidize some bromine as active sanitizer.

Anyway, as of midnight, about 7 hrs after fill, the tub was reading pH 7.8 (not sure why it went up so much from 7.2 - maybe aeration, despite the low TA?) | TA 50 | CH 100 | some presence of bromine | 96 degrees. Wife and I thought we'd give it a try since we waited all day, as parameters were in ranges. Soaked about 20 minutes. After we got out, I decided to give it a shock dose of the MPS (I assume that's what potassium peroxymonosulfate is, though I keep seeing potassium monopersulfate - is that just a difference in how the name is written?). I couldn't find MPS on Pool Math so I under-dosed according to directions on the bottle, and added about 2oz around 1am last night.

So as of this morning, the testing reads pH 7.5 | TA 40 | CH 100 | high presence of bromine according to OTO test - question below | 100 degrees. I think the MPS has some properties that would lower the pH/TA a bit? Water looked nice and clear. The only thing I noticed is that around the waterline, there was some... scum? Not really scum. Looked like a sort of off-white powdery/granular dust, but when wiped with a finger it sort of accumulated into what I can best describe as a blob of dead skin/grease, but not sure if that's what it is. For what it's worth, we'd both already showered before getting in. We'll probably never be that clean again upon getting in, haha. So my questions:

1. Is accumulation around waterline as described a normal occurrence in acrylic tubs? I don't think I'd ever been in one before. Is something off, or is that just something I'll be wiping regularly? It was mostly in the area of seats we had been sitting in, but not exclusively there.
2. I'm not great at reading the OTO color blocks. I usually use that to test for general presence of sanitizer. Can the FAS-DPD (chlorine) test be used to test for sanitizer amounts, and then multiplied by 2.25 to get exact bromine level? I did that this morning, and got 5 FC => 11.25 bromine, which aligns with the dark yellow OTO test. Is that valid?
3. Never used MPS before - is that what I have? - and for my system, will I only be using that as a shock oxidizer periodically as needed? Should I be adding any sanitizer (MPS is not sanitizer, itself) on each soak, or is that what the bromine feeder/bromide reserve/ozone system is for? I can also use 10% liquid chlorine for shocking, I just won't have any on hand until this weekend when I'm opening the pool, so I used MPS to get started with an initial shock of the water last night. I probably will, as I'm more comfortable with handling that. Does that mean I'll calculate enough liquid chlorine to raise FC to 4.5 => ~10 bromine for shocking?
4. Did anything in my process above stand out as a bad thing? I'm new to hot tub care, but not gonna lie, I have sort of come to enjoy my water chemistry. I just want to make sure I'm getting off on the right foot and don't have anyone to personally ask for experience. If I'm following the sticky, I'm aiming for those numbers - TA 50-60 | CH 100-125 | pH 7.4-7.6 | active sanitizer bromine 4-6ppm | 98-102 degrees based on bathers
5. I'll be back to ask later about drains and refills. I like the people at the pool store on a personal level - they're friendly. But I don't really trust all their advice. I take it with a grain of sodium chloride.

Thanks for anyone who made it this far and anyone who chimes in. Happy pool season, everyone.

 

[bpardy]

I have only been running our bromine hot tub for about 1.5 years at this point so I'm no expert, but I have some experience.

Adding a slight excess of the sodium bromide should be no problem at all. Worst case, it just means your bromine levels will spike higher than they would have otherwise if you were to add more MPS or chlorine than needed (meaning it would take longer for the bromine levels to come down to where it's safe to use the tub for a soak - in a pinch you could add thiosulfate to quickly bring down an excessive bromine level though).

The scum at the waterline is concerning though. I do not generally see that after a soak, certainly not one where all bathers were fresh out of the shower and not covered in skin/etc products. I and most others here highly recommend purging even a brand new tub to eliminate biofilms that accumulated after manufacturer wet-testing of the components. Ahh-some is highly regarded here as probably the best purge product. On a new tub you may need to run multiple sequential purges to fully clean it out (my 180gallon bromine tub took about 5 purge cycles when it was new to get colorful gunk to stop coming out).

I use a Taylor test kit keyed for bromine so I can't speak to the chlorine->bromine conversion but someone here will set you straight on that. I think you probably have it correct.

MPS is indeed the product you have, it goes by multiple common names. Generally I add MPS after each soak to oxidize bather contaminants and convert bromide into bromine. The bromine tabs in your feeder tube will slowly break down, releasing chlorine which will also convert bromide into bromine, along with releasing small amounts of bromine itself. They work with the bromide bank to help you maintain a >0 bromine level, but they are not really a substitute for adding MPS (as I do) or chlorine bleach (as most others here do) after a soak. I think of them more as being helpful for the cases where the tub is not used for a few days to help maintain bromine levels (vs daily chlorine additions either manually or via a SWG as non-bromine tubs require).

If you get foaming during use you may want that calcium level up closer to 200ppm.

But at this point I think your best bet is to purge the tub thoroughly with Ahh-some (making sure you have high bromine levels at that time to help kill off anything dislodged), drain, refill, rebalance. It's a good time to pick up some more startup chemicals beforehand, specifically the sodium bromide you're out of now.

 

[sweetgerald]

Thanks, I've had mine for 1.5 days so I value your experience!

Makes sense, re: the excess sodium bromide - the 4tbsp of MPS would be to oxidize 250 gallons according to the bottle so it'd under-dose my 325 gallons. If I have abundance of bromide, that could be why. I don't know what "too high" of a spike is - I measured it at 11.25 bromine roughly, using FAS-DPD, converted to bromine by factor of 2.25. With no experience, I'd wager that's not an insane number. And being day 2, I don't know what longer than normal would be to come down (a day? two?), but I'll be taking it a little lighter on the MPS (or chlorine) when I need to oxidize, until I know the relationship well.

Purging the brand new tub would have hopefully been a dealer recommendation, but unfortunately was not. I think I'll give this some time to see if that's a need. Something to file away for just-in-case over the next couple days or weeks. I don't know how to describe it - maybe scum is wrong word. It's sort of a dryish white... residue resting from the water line, to a couple inches above the water line (when no jets running). Sort of "sticky" to wipe off. As in a couple swipes over it with my hand. I didnt take a picture. Is it possible it is a residue from how I added the calcium increaser, sodium bromide power, or (too much?) MPS powder, or baking soda? Each was added to the center of the tub with jets running at full bore. Could that be carried up above the waterline by the moving water and stick there when jets stop? There was no such residue noticed around midnight when we went in, but the water was bubbling, and the last chemical addition was 4tbsp of MPS powder, which to my novice understanding seemed seemed like a lot, but also seems to have properly brought the bromine up to shock levels a bit > 10ppm.

Glad I have a general understanding of the idea of the bromine feeder. That's what I assumed it to be - a residual sanitizer level between uses, helped by adding a little oxidizing agent after usages.

Thanks!

 

[sweetgerald]

As a follow-up, as of a couple hours ago, the bromine level had dropped to 4-6 or so. I did purposely leave the cover off during a filter cycle, so that what little sun we have today could assist in burning off some sanitizer, as my son wanted to give it his first try and I wanted to ensure the level was appropriate. As I write this, I can hear my family enjoying their new spa to the sound of Kidz Bop playing on the speakers as I'm up here working.

 

[bpardy]

11.25ppm of bromine seems fine to me, mine is frequently that high the next day after adding 1oz MPS after a soak. I'm not sure if there is a number that is "too high", only a matter of if you are raising the bromine so high that it has not yet come down to ~5ppm before you want to use the tub again. In my case the tub is used roughly twice a week so I don't mind if it takes a few days to come down to usable levels. You'll get this dialed in with experience over time.

The sidewall deposits might have simply been precipitated calcium if you added several chemicals together without letting enough time pass in between separate chemicals. Just keep an eye out and see if something similar happens now after your son uses it and do consider the purge if so (especially if you see anything green/yellow/brown). Definitely if you get a ton of bubbles from strong jets or serious foaming, stuff can and will end up above the waterline. Even swimsuits with leftover detergent in them can cause that.

Good luck and enjoy!

 

[JoeSelf]

Purge that puppy with Ahh-some! will clean out the BIO-Film you are seeing. That is most likely the scum your are seeing.

 

[sweetgerald]

Thanks for the input. I get the sense that Ahh-some! is a well-liked product for what it does. No doubt I'll be picking some up for my future water changes.

Is it possible it might be calcium on and above the water line, following first addition of calcium to the tub? I was doing some image searches for "white powder on walls of hot tub" and found these images. The first image, showing a little bit of buildup on the black there, is what it looked like on my waterline and above it - mostly where we had been sitting, and the jets were pushing water up behind our shoulders. Off-whiteish. When I'd swipe a finger across it, it'd leave a waxy feel as it clumped together as I swiped and was a color similar to what the other image has in hand. A little tan, but obviously way less amounts. Like I said, I added Sirona Calcium Booster with jets running full blast with all the bubbles going, after initial fill. I'm certainly going to keep tabs on this for the first week or so, and see if there's any further deposit of film.

 

[The Mule]

You are absuletely on the right track.
I bought a new hot tub last fall, after not having had one for 4-5 years, and was absolutely amazed at how much crud and scum was in a BRAND NEW hot tub! What you show in the pic and describe is what is called biofilm--scum--on this forum, and it is not "normal" or acceptable.

As others have said, Ahhsome just plain works. It is basically the ONLY product you will see mentioned by name on this forum.

My tub is a ~130 gallon one. I add an ounce or so of crushed bromine tablets to the initial fill, and then re-activate it with about 1 oz of ~6% bleach after each use (2 people x 15-20 minutes a day). I too have a case of unused chemicals with no labels that the dealer kindly gave me....now I'm the proud new owner of 10 lbs of HAZMAT material.
The excess bromine that gave you the initial high readings will get deactivated/used up shortly, and then you just adjust your dose of MPS to reactivate it up to the proper level of free bromine.
I don't think you need the constant feed of bromine from the dispenser. Once you get the initial bromine reserve established (which you did with the first dose) you just reactivate that bromine with MPS, or bleach.

 

[Ahhsomeguy]

It really is amazing. The poor guy with the new hot tub was never schooled on biofilm. A new hot tub owner just can't possibly understand why they should purge a new hot tub. It's got to be something else. My this and that testing are at correct numbers. Perhaps it is just the? Maybe I'll get that Ahh-Some stuff to purge the tub on the next water Fill. We'll see. Perhaps this scummy stuff will just clear on it's own. It falls back on the same old story. People hate to drain their hot tub. Hot tub owners who purge and drain on a regular basis are enjoying the best quality water without the maintenance fuss. There are a few hot tub manufacturers that are training their dealer network regarding the benefits of purging periodically. Those dealers are selling more tubs because their customers are not having water or scum issues. Unfortunately, many manufacturers and dealers don't want to raise the issue prior to or after the sale. Are you nuts? Don't blow the sale by telling potential customers about biofilm. This is a huge mistake. Thank you to the forum posters who are telling people about biofilms and how to remove them. You are to be commended.

 

[sweetgerald]

Thanks all. So far, so good, I think. 5 days in now, and all water parameters have for the most part stabilized. pH seems to slowly be creeping up but otherwise good. There have been no further deposits along the water line since the morning after I made initial chemical additions. This is not to say that I discount the presence of organics in a new tub's plumbing. Moisture and heat breeds... stuff. No doubt about that. I'm sold on the merits of clean fill water. Wife was excited to start using the tub, so I figured I'd at least give it the first week, monitoring it, until I'd have time to get some AhhSome and do a proper purge and fill anyway.

Per the owner's manual, I have now set the tub up for two 6-hour filter cycles (which includes ozone on). Dealer had said two 2-hour cycles is enough to turn water over four times per day, during his installation. Perhaps that much is true, but manufacturer recommends 12 hours per day for oxidizing/sanitizer purposes. That may also be overkill the other direction. Daily testing shows that with even a little bit of the bromine feeder open, the bromine level is over 6 (using FAS-DPD test for FC => 3 * 2.25 = 6.75). I've kept dialing that down during this first week and may resort to emptying or closing the feeder tube entirely. It seems that the ozone is doing its job. Even after a couple brief soaks (2 clean adults x 15 minutes), the automated cleanup cycle that kicks on a half hour after manual jet activation spiked the sanitizer levels back to greater than 6 and held it there overnight.

Should I be bonking it with some oxidizer after each use, either MPS or 10% chlorine, even though the ozone/bromine feeder is keeping levels up? Is the goal to get to shock levels after every time the tub is used? Or should I expect to get the sanitizer to shock levels only weekly-ish. Following the steps here lead me to believe that I'd only be raising to shock levels on interval, and adding oxidizer after every use (while not hurting anything) wouldn't be fully necessary provided my ozone/feeder is dial in. Of course, if we have 4 or 5 adults in for an extended soak, that would be cause for a good dose upon exiting.

EDIT: Is there a difference as to which AhhSome to purchase? I see 2oz and 6oz gel tubs, and a 16oz liquid. Gel says warm water, liquid says any temp water.

 

[Armor77]

I recently purchased a new hot tub 315ga Arctic Spa with ozanator and will be using bromine as a sanitizer. Big learning curve here for us as this is our first real spa. I will be purging with AC after filled and before initial first time use. Regardless what set up says or dealer, after reading and researching on TFP and talking with experts on this forum that is the route I am taking even it takes longer to be able to enjoy. It will be worth it and peace of mind will result. That being said I will also incorporate the AC weekly regimen, because come winter I do not want a mess of probs, as it is a long winter lol.