Question about 3-step bromine spa

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K

Krulligo

Well-known member
May 18, 2022
148
Toronto
Pool Size
4600
Surface
Vinyl
Chlorine
Liquid Chlorine
I have ran a spa for 2 years now and this is my third, so still learning. For both years, spa has been maintained via pool store suggestions. After a few struggles the first year, with a much better 2nd year. I am deciding to separate from the pool store and go with the 3-step bromine spa method outlined here. Spa is 390 g (1500 L).

This past Saturday - I gave the spa a purge and clean, and refilled with fresh water (from municipal tap). Without adding anything chemicals yet, measured TA=110 ppm and pH=7.6 (this is quite usual and consistent with our tap water). I then added 50 g of Sodium Bromide (>95% purity) to establish ~30 ppm bank (pre-dissolved). Let the jets run for 15 mins then added 140 ml of 12% chlorine to shock. Let the jets run, and then measured bromine level and it was >10 ppm which all looked good. Threw a couple bromine pucks in a floating dispenser into the spa and called it a day.

Sunday - I remeasured TA=110 ppm. The pH rose to >8.2 so I did an acid demand drop test and adjusted with Muriatic acid. Re-measured pH after and it was 7.6. My family (2 adults + 1 toddler) used the spa that evening for about an hour. Water felt good.

Monday (about 12 ours after we used the spa), I quickly measured bromine levels and it was much lower then I expected - somewhere between 0-1 ppm. Re-measured TA=110 ppm and pH=7.6. At this point I added another shock (140ml) of 12% chlorine. Bromine shot up once again to >10 ppm.

My questions are, did I do everything correctly to set up a bromine spa? And also, Why did my bromine level drop so low on Monday. I was expecting to shock only about once a week, while my bromine puck dispenser was suppose to maintain bromine levels throughout the week (in this case I had to shock 48 hours later). Is it that because we used the spa the evening before, most of the available sanitizer was used up? Still learning here and thanks in advance!
 
Based on what you wrote the Bromine setup seems reasonable. After two person-hours in my spa I add 4 ounces of 6% chlorine then place the floater back in the spa. I view the floater as there to maintain the sanitation between uses - not to replace/reactivate sanitation from spa usage. You have to add bleach to get the sanitation back up to a normal level. I use a Pentair floater, place 4 1" pucks in it and set the floater to 3 or 4. You will have to experiment. If you measure the bromine level after usage Poolmath will tell you how much bleach to add.

A TA value of 110ppm would be very high for my spa and the pH would certainly drift over 8 when I turned on the jets. I get my TA down to 50 or 60. I had to separate the sanitation method from the water balancing (TA, CH, pH, borates). The water balance techniques are described in the Chlorine sticky.

What test kit are you using?
 
Thanks Mike that makes sense. I will get into the habit of adding a couple ounces of 12% chlorine after each heavier use (in addition to the weakly shock) to reactivate some bromine. I will also monitor bromine level more closely to see what type of routine works for my spa and usage.

I am a bit confused about TA in a spa. Some suggest it to be 80-120, while some suggest it to be much lower (around 60 as in your spa). I am very unclear at what the "proper" amount should be. Do you want it to be lower cause there is so much aeration of the water which causes pH to go up? So the more usage of the spa with the aerators open, the lower you want the TA to be?

I am currently using this drop test kit:

Also when measuring pH, I double confirm it at work using a scientific laboratory grade pH meter (both give me nearly identical results)

Unfortunately, here in Canada it is difficult to find a Taylor kit. However, I tested the home depot kit against the a friends Taylor kit that he bought in the US, and the results were quite consistent between the 2.
 
Many manufacturers and pool stores suggest 80-120 but those number will not work for me. The pH drifts high every time. I use 50-60 for the reasons you mention. I use granular boric acid (borates) from Duda Diesel and the pH doesn't move much. The bromine tabs will drive the pH down a little. I use 20 mule team borax to raise the pH but baking soda works. Poolmath will show you the effects of each and how much to use.

As a note - I never shock my spa unless I'm doing a purge with Ahh-some hot tub cleaner. I've not found it necessary and makes the spa unusable until the bromine level gets down to 8ppm.

If you can't find the Taylor 2106 check into the TFP kit.

You don't mention calcium hardness. My replacement water is about 40. I raise this to 120-150 or the water will foam.

Your signature states you have a chlorine pool. I have no experience with pools. I recall reading that going from the pool to spa isn't an issue but going directly from a bromine spa to a chlorine pool could introduce bromine which may not be what you want. You may want to research this.
 
Yea I noticed I have struggled with pH drifting high past couple of years. I will try to see how hard it is to maintain at those TA levels but if it becomes an issue I will try dropping it on next refill. Thanks for the tip on the borates and the shocking. So you just maintain the bromine in range and unless the water is looking a bit cloudy you don't bother to shock at all?

Unfortunately the TF kits are even harder to get here. The website doesn't even offer a shipping option to Canada. My plan was to pick up one of these kits when visiting the US but then covid hit.

Water hardness hasn't been an issue for me. Tap measures 130 ppm for me and currently no issues with foaming. Yea I remember reading about the potential issue going from hot tub to pool and introducing bromine so we try to avoid that and only go pool to hot tub.

Your replies have been very helpful. Thanks again!
 
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My water has never gotten cloudy - knock on wood. I rinse the filter once per week. I have found it much easier to maintain levels with TA lower. Fewer chemical additions because I'm not chasing pH. If you keep adding dry/muriatic acid to offset the pH rise the TA will eventually get where it wants to be and stabilize and my guess is TA will be 50. I had to do a lot of water testing to characterize my spa but now it's easy.
 
If maintaining appropriate sanitizer levels, your water should not go cloudy. I only ever experienced cloudy water if I ignored regular testing and additions and all the sanitizer got used up.
 
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