Shorten Water Balance Time In 3 Step Bromine Refill

[Geoffrey]

I'm hoping I can get some guidance on shortening the amount of time it's taking me to get my basic TA and PH balance when doing a fresh fill on my hot tub. I've been using the 3 step bromine method and try to follow the steps in Waterbear's and Nitro's sticky posts. I generally end up getting things balanced, but it is taking 4 - 5 days to get CH, TA, and PH in the zones - before I can sanitize.. and I assume that's not a good thing.

I have a 225 gal. rated tub, so I assume about 200 gal. capacity. I fill from a municipal water source run through a household filter. My source water has been pretty consistent over several fills, usually:

TA: 30-40

CH: 20 - 30

PH: 7.4 - 7.7

My usual procedure has been to adjust TA with baking soda and CH with pool calcium. Of course, this results in PH going very high. Using the Taylor kit for acid demand, I add acid (mercuric) at the recommended amount. And this is where I find the adjustments start taking a lot of time. When I test again a few hours later, there is almost no reduction in PH. Redo the acid demand, add the recommended amount... repeat....repeat. Even when I have 1 drop on the acid demand test move me from above 8 to 7.2 in the test - adding the recommended amount of acid shows minimal or no discernible difference.

Eventually I get there, although usually with the TA lower than I would like in the 70 range. Up until this last fill I would add in Borax at this point. When I've used it, it really held the PH dead steady. But, since adding it pushes the PH back up and requires the same repeated acid adjustment problem as above, I skipped it last time. But, I had to make a lot more weekly PH adjustments as a result.

Any suggestions on where I might be missing something - or different products to use - or revision of my order would be greatly appreciated. Not only do I have concerns letting the water sit there for several days without being sanitized, but it's really hard to go a week without a soak!!!

I have learned so much from these forums and can't thank you enough for the great effort you put in here!

[waterbear]

IF your pH is staying too high it is from outgassing of CO2 (which causes pH to rise) and it means your TA is too high. It is probably because your tub has a lot of aeration. (Do you have an ozonator?). Just don't raise the TA that high. Try it around 50 ppm and see what happens.

[Geoffrey]

Thanks Waterbear. I'd been trying to get an initial TA of around 80+ before making any other adjustments (per your sticky post). The tub doesn't have a lot of jets, but it's a pretty small volume of water so it's probably still getting a lot of aeration. It does have an ozonator, but without a bulb change in 10 years I doubt it has a functional ozonator. LOL

I just did a fresh refill this afternoon, so I'll give a try with an initial TA of 50. Should I consider bumping up the CH a bit with the TA that low? I'm usually around CH 100-110.

[waterbear]

I just did a fresh refill this afternoon, so I'll give a try with an initial TA of 50. Should I consider bumping up the CH a bit with the TA that low? I'm usually around CH 100-110.

No reason if you have an acrylic spa.If it is a plaster spa then 100-110 ppm CH is WAY too low and the water would be agressive to the plaster finish but with an acrylic shell it's not a problem. I usually like the CH around 130 ppm because that amount of hardness will help deter foaming more than a lower hardness (which is the main reasin to add calcium to an acrylic spa) and you will not really have to worry about scaling.

[Geoffrey]

I'm still looking for the quickest way to get my fresh fills balanced and sanitized for a 3 step bromine set up. Just happens I had a leak that needed repairing, so I've made another fresh fill this week. I'd appreciate any input on my sequence and if my current balance seems to be on target for what I want to maintain with my 200 gal. acrylic tub.

Original numbers are:

TA: 30

PH: 7.6

CH: 30

Borate: 5

My sequence was adding baking soda and calcium to reach

TA: 50

CH 130

I then added Muriatic acid to drop PH close to 7.0, followed by 10 oz Borax. After allowing to circulate a couple hours, I added more acid on intervals (about 2 oz per 1/2 hour) to bring the PH back down - uncovered with circulation, but no jets on. (Incidentally, last 2 fills this takes about 2x the amount of Acid suggested by the pool calculator in the increasing borates box.)

When I reached a PH level below 8.0, I allowed things to rest overnight. Adding another dash of acid in the morning has left me with these numbers:

TA: 50

PH: 7.7

CH: 130

Borates: 50

1 oz sodium bromide and 4 oz 6% bleach to shock put my bromine at 5ppm after a hour of uncovered circulation.

Assuming I'm fairly stable over the next couple days, does it sound like I'm on target with a balance I should maintain and have a sequence that is as efficient as possible? I'd welcome any input or tips.

BTW - this tub was run several (over 10) years blindly following local spa shops recommendations, simply adding calcium based on their water testing printout. Their CH target was 200 - 400. Since switching to the 3 step bromide method I've done several fills with a lower CH. There's always a noticeable amount of (I assume) small particles of scaling that shows up immediately in the water. I haven't noticed the CH going up over time between fills, however.

I assume the lower CH is letting scaling that's built up on the plumbing to sluff off? Should I periodically pull out those particles? (easily done with a shop vac!)

Always grateful for the generosity of the guidance offered here. You guys are the Boss!

[waterbear]

sounds like you have things well under control. Your numbers look excellent.

As far as the scale particles go...are you adding the baking soda and calcium together? You need to wait several hours after adjusting one parameter before adjusting the other or you can cause calcium carbonate to precipitate out (because of locally high pockets of high concentration). By waiting you allow the chemicals to dissolve and circulate fully. If you are precipitiating out calcium carbonate you will most likely see a drop in TA or CH or find that your dose does not put you where you thought it would.

It is also entirely possible that you have scale buildup in the pipes or heat exchanger and it is now coming off because of the lower calcium level in the water. If this is the case you should not really see any impact on CH or TA levels.

Your filter should catch the particles and rinsing the filter should remove them.

[Geoffrey]

Thanks for the great guidance as always, WB. I have been adding the baking soda and calcium at the same time recently. I'll make that change next time and start with the calcium, then add the baking soda after some hours delay.

Your earlier advice to reduce the starting TA to 50 was really helpful. Doing that instead of starting with a target TA of 70+ has allowed me to get my PH back to acceptable levels quite quickly. Then I can add the borates - after which bringing the PH back down does take more time, but that's to be expected once the PH buffers are in the mix.

I think I am looking mostly at scale build up coming off the pipes and heat exchanger. The filter catches some, but mostly they gather in a couple low spots and never reach the filter. I'll just suck them out occasionally with the shop-vac - for aesthetics if no other reason.

It's taken about 18 months and 5-6 fills to feel like I've finally got this down reasonably well and now have a reliable and systematic approach for fresh fills and maintenance. I couldn't have done it without all the help and assistance from all the experienced folks who generously contribute to this forum. So a sincere thanks to you all.

[arches2]

The other thing you could do when adding the borax is disolve it in a 5 gallon bucket and put the calculated amount of acid in with it. I've found that this gets me real close on pH quickly and i don't have to spend (hardly) any time chasing the pH after adding the borax.