New hot tub and lost on chemicals

[Shane112358]

So I have a 250G hot tub and figured it would be easy to learn the ins and outs of the chemical situation having cut my teeth on a new pool earlier this year. Well I guess I was wrong.

I first tried bleach as chlorine and I would add a few oz to hit my 3ppm target but it was not showing any FC. In retrospect this was after initial bathing and perhaps the FC was getting consumed right away, hence it not showing in a test. I kept adding more bleach until I hit 3ppm.

Then I made the mistake of putting brominating tabs with DMH into my feeder, thinking I could just hot swap from chlorine to bromine and set it and forget it, haha.

Came back a couple days later and I’ve got cloudy water and no Bromine or Chlorine. I tried adding bleach to hit 4ppm but it didn’t show. I was also at TA of 210 and pH 8.3 so I added a teaspoon of 14.5% MA to bring me down and start the reduction of TA. An hour later the pH had only gone down to 8.2 and still no FC. I started doing research and learned I should not have hot swapped chlorine to Bromine so I drained, cleaned filters and flushed pump with fresh water. I’m now refilling it and deciding what to do.

I don’t have sodium bromide on me to start a bank and I feel like I have a decent intuition on chlorine so I’m thinking I just run with that, using only bleach and checking every day or every other along with chlorine tabs. Or maybe no tabs and manually bleach and CYA as necessary.

I just checked fresh water and I’m at pH of 7.6 and I presume similar TA around 200. So I think my plan is to reduce to 7.2 with MA then add bleach to get to 3ppm FC. Advise on that and application of CYA is welcomed or perhaps just, am I over thinking that bromide approach? So far I have no chemicals so I can decide what to do here, I’m not committed either way.
Thank you!!!

 

[jseyfert3]

You can switch from chlorine to bromine no issue, it's the opposite direction you cannot do. However, once your water is cloudy, it's easiest to dump and refill. You can SLAM to fix it, as I did when I let mine get cloudy one time from neglect, but it's not worth the effort. The best thing to do is to maintain sanitizer appropriately so it doesn't get cloudy.

I, and many others, use chlorine only. I'd second your choice to just run with chlorine.

Advise on that and application of CYA is welcomed

20-30 ppm of CYA is recommended for a hot tub. You can either use dichlor on a fresh fill until the CYA builds up or you can add straight CYA right off the bat. Since I have straight CYA for my pool I've personally transitioned to straight CYA on a new fill then switch to bleach, I find that slightly easier then using dichlor, but either is fine.

I just checked fresh water and I’m at pH of 7.6 and I presume similar TA around 200. So I think my plan is to reduce to 7.2 with MA then add bleach to get to 3ppm FC.

You'll need to drop that TA to keep pH rise manageable. To do this you do the acid/aeration method. Generally I like doing this immediately on a new fill, before the water heats up. Either way works, but if the water hasn't heated up you'll loose less energy during the acid/aeration.

To do, open up all air valves and run your pumps or whatever you do on your spa to add bubbles. You want as many bubbles as possible, the "aeration" part of this. Check after 15 minutes or so, the pH will likely be 8+. Put the pH and TA into PoolMath to calculate the acid addition needed to drop the pH to 7. Add the acid and start the pumps/bubbles again. Check after another 15 minutes. I usually use my pump time-out timer of 15 minutes for this. If the pH isn't back to 8, start the pumps/bubbles again. After another cycle the pH will likely be back at 8. Measure your TA, put the TA and pH into PoolMath, calculate the acid addition to target a pH of 7, and repeat. Each time you need to measure TA, because as the TA drops the acid needed to drop the pH to 7 will become less and less.

Once the TA gets down to about 80, you should notice the pH is taking longer and longer to climb. At this point I generally start using the tub, as the pH rise is a bit more manageable. After each use I check the pH and use PoolMath to add acid, targeting a pH of 7.4. Once the TA gets down near 50 ppm, switch your pH target to 7.6 and don't add acid until the pH climbs to above 8.

Be sure to maintain the FC based on the CYA level. For a CYA of 30 this would be 4-6 ppm of FC. I've found it helpful if we're going to have a long soak to raise the FC to the SLAM level before we get in. Generally most of the FC is used by the time we get out (depends how long you soak, test after soaking until you get a feel for this), and I raise the FC back up to SLAM levels after getting out. You'll need to pay extra close attention to the FC level for a few days after a soak as the chlorine slowly breaks down bather waste.

I know this is a lot to take it, but it's a bit easier than it sounds, though admittedly a bit tedious. But it is possible to maintain crystal clear water with a constant level of FC with the appropriate testing and addition of bleach. Let me know if you have any questions about this or something else, I'm happy to help!

 

[Mdragger88]

Just to add to the above - please don’t use trichlor tabs in your tub - they are very acidic & dissolve too rapidly in the hot water. Its not good for your equipment.
Have u done an Ahhsome flush? It’s recommended for even new tubs as they can contain biofilms leftover from the factory testing which can lead to increased chlorine demand.
After that the dichlor then bleach method should set u right. here’s the write up on that which includes info on lowering ta

How do I use Chlorine in my Spa (or pool)?

If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...

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If it’s too much to add bleach daily you may want to look into a drop in swg like the saltron mini or chlormaker that does it for u so it never gets low. As @jseyfert3 stated you need to dose to shock level for your cya when u get out - it won’t be harsh with the cya. 3ppm isn’t enough wiggle room - that can be used up in a 30 minute 1 person soak easily & definitely won’t last for two days. You always want to have residual fc or else u just have bacteria soup.

 

[Shane112358]

Thanks guys I will reply in full in a bit once I process but quick question - I realized I had two bromine DMH tabs in a floater for about 10 minutes while starting to fill the pool. There is no concern with starting with Chlorine given this very tiny amount of Br in there, right? It shows 0.0 on a chemical test.

 

[Shane112358]

Okay so I’ve added chemicals to target 30ppm CYA, 7.0 pH and agitating, and 5 ppm FC.

Checked levels after 15 minutes agitation and got 3ppm FC and CC and pH 8.2.

I’ve added a little more bleach and MA again targeting pH 7 and will repeat the process until my pH rise levels off.

 

[Mdragger88]

I wonder if your bleach isn’t the strength it says/used to be or maybe your calculated volume is off a touch.
most people can confirm their volume w/ their acid additions . Just keep doing the aeration & when ph rises above 8 lower back to 7.0/7.1 & the ta will drop w/ every cycle. You want ta around 50/60 so it will take a bit of time. But not as long as when dealing w/ a pool. You don’t have to do it all today. Doing it in Stages is fine.
Not sure about the bromine tabs but 10mins ain’t much time so hopefully no harm no foul. I would target fc 12 initially if i were u seeing as you have had instances w/ no fc. A spa is just like a pool in that u can swim w/ fc up to slam level for your cya. Where it differs is the level of bather waste/organics that consume chlorine- its a way higher percentage than in a pool since the volume is so small. Its like 75 people being in your pool at once. Don’t be stingy w/ the bleach lol if it’s a little too high it will come down pretty quickly especially if u use the spa (since you’re organic) whereas a pool will only lose a 2-4ppm in a day even with bathers.

 

[Shane112358]

Thanks. Yes I suspected that on the last go around. The bleach says 5.25 on the label but the SDS online for it says 2.75-8%. I wasn’t sure before because the previous bathing loads could have consumed the FC before I had a chance to measure but this time I am quite sure based on what I’m seeing. Even when I targeted 5 from 3 I only got halfway there to 4. So I suspect the bleach is actually like 3%. I’m going to start using that in my forward calculations with this product. The volume is correct and actually may be high based on what I see online. I measured it myself to be sure. I’m going up to 7 to 8 in 15 minutes over and over now. I’m on my 4th drop of MA and waiting to test again.

					I wonder if your bleach isn’t the strength it says/used to be or maybe your calculated volume is off a touch. most people can confirm their volume w/ their acid additions . Just keep doing the aeration & when ph rises above 8 lower back to 7.0/7.1 & the ta will drop w/ every cycle. You want ta around 50/60 so it will take a bit of time. But not as long as when dealing w/ a pool. You don’t have to do it all today. Doing it in Stages is fine. Not sure about the bromine tabs but 10mins ain’t much time so hopefully no harm no foul. I would target fc 12 initially if i were u seeing as you have had instances w/ no fc. A spa is just like a pool in that u can swim w/ fc up to slam level for your cya. Where it differs is the level of bather waste/organics that consume chlorine- its a way higher percentage than in a pool since the volume is so small. Its like 75 people being in your pool at once. Don’t be stingy w/ the bleach lol if it’s a little too high it will come down pretty quickly especially if u use the spa (since you’re organic) whereas a pool will only lose a 2-4ppm in a day even with bathers.

 

[Shane112358]

Wow that was a brick wall. Went from increasing from 7 to 7.9 in 15 minutes, with one additional drop of MA I ended up at 7.3 and 40 TA. So I’m going to agitate more, see where I end up on TA and use baking soda to get back to 70-80 if needed.

 

[Shane112358]

I settled to 7.6 and 40 TA. I’ll check in the AM and then if needed add baking soda to get to 70-80.

 

[mknauss]

Leave the TA at 40. Only raise it if the pH becomes unstable.

 

[jseyfert3]

Wow that was a brick wall. Went from increasing from 7 to 7.9 in 15 minutes, with one additional drop of MA I ended up at 7.3 and 40 TA.

Yup, that's why I recommended the testing TA and using PoolMath each time. It gets really touchy to acid additions at a low TA. You should find the pH is fairly stable here, rising a lot slower. At this point don't add acid until it reaches 8 and when you add acid don't target anything lower than 7.6.

 

[Shane112358]

Yup, that's why I recommended the testing TA and using PoolMath each time. It gets really touchy to acid additions at a low TA. You should find the pH is fairly stable here, rising a lot slower. At this point don't add acid until it reaches 8 and when you add acid don't target anything lower than 7.6.

Thanks all. One question. To be clear, you're suggesting to SLAM (FC target 12 ppm) after every use? Do you measure pH and then SLAM, or could I more or less assume my FC is in the 2-3 range after a bath, and always use the same amount assuming it's not multiple times a day? I'm fine with either but obviously I'd prefer to just throw in a standard volume when I get out instead of taking a sample, checking FC and then putting it into PoolMath.

 

[Mdragger88]

Test every time for a while so u can be reasonably sure where u are after normal soaks & how quickly you lose fc etc.

 

[Shane112358]

Makes sense, thanks.

 

[Shane112358]

Yup, that's why I recommended the testing TA and using PoolMath each time. It gets really touchy to acid additions at a low TA. You should find the pH is fairly stable here, rising a lot slower. At this point don't add acid until it reaches 8 and when you add acid don't target anything lower than 7.6.

BTW I have a similar Intex pool as you and just saw your skimmer. Nice work on that. I have the Intex skimmer, which does a fine job but your implementation is much better.

 

[jseyfert3]

Test every time for a while so u can be reasonably sure where u are after normal soaks & how quickly you lose fc etc.

Yeah, this. Eventually you will realize how much FC you use, and you'll naturally switch to just dumping in a fixed amount when you get out. That's what I do now, generally.

BTW I have a similar Intex pool as you and just saw your skimmer. Nice work on that. I have the Intex skimmer, which does a fine job but your implementation is much better.

Thanks! The skimmer helped out tremendously with getting leaves and such out of the water before they would sink to the bottom. Pretty easy install, except for the always present fear of poking holes in and cutting the liner, since that obviously voids the warranty.

 

[Akathisia]

The recs in this sticky have been foolproof for me over the past 5.5 years.

How do I use Chlorine in my Spa (or pool)?

If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...

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