New hot tub owner with sanitizer and water chemistry questions

JVTrain

TFP Expert
Feb 3, 2014
5,081
Central Minnesota
Awesome! Your pH rise after adding is due to the aeration of filing and jets running. Very normal. The FC level you measured is correct. Likely you have a bit more water than 395 gallons and/or a little of the FC was consumed by some organics.

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cpd5215

Bronze Supporter
Jul 2, 2016
44
Columbus/OH
Awesome! Your pH rise after adding is due to the aeration of filing and jets running. Very normal. The FC level you measured is correct. Likely you have a bit more water than 395 gallons and/or a little of the FC was consumed by some organics.

Sent from mobile device. Beware of brevity and spelling errors!


Awesome! I am starting to love this chemistry stuff!! I just tested again and pH dropped to 7.5 but from what I understand that is normal. I will continue to monitor and report back tomorrow after I test and see how things are looking!

Thanks again JVTrain!! You have no idea how happy my wife is(and me too!) that we have "normal" looking water without adding all those chemicals I had in there before and it still didn't look good, at all.
 

JVTrain

TFP Expert
Feb 3, 2014
5,081
Central Minnesota
Awesome! I am starting to love this chemistry stuff!! I just tested again and pH dropped to 7.5 but from what I understand that is normal. I will continue to monitor and report back tomorrow after I test and see how things are looking!

Thanks again JVTrain!! You have no idea how happy my wife is(and me too!) that we have "normal" looking water without adding all those chemicals I had in there before and it still didn't look good, at all.

That's the most important thing, keeping your spouse happy! Those mineral cartridge systems really can ruin a good thing. Perhaps if your fill water were higher initial pH you never may have noticed as much, but eventually you would have gotten that yellow/green hue. Better off without it!

Glad we could help. That's what keeps us coming back; being able to help folks with their pools and spas from the comfort of our jammies. :dwarf:
 

cpd5215

Bronze Supporter
Jul 2, 2016
44
Columbus/OH
That's the most important thing, keeping your spouse happy! Those mineral cartridge systems really can ruin a good thing. Perhaps if your fill water were higher initial pH you never may have noticed as much, but eventually you would have gotten that yellow/green hue. Better off without it!

Glad we could help. That's what keeps us coming back; being able to help folks with their pools and spas from the comfort of our jammies. :dwarf:


LOL very true!

We used the tub last night for an hour..There were three of us. All pretty sweaty and dirty I think. Before we got in, the FC was 5 and when we got out it was .5(took with drop kit both times). I was looking to get the FC back up to 6ish so I added .5oz dichlor. When I woke up this morning and measured FC, it was barely readable. Did i underestimate the amount needed to clean the tub. I assume so. If I understand the process correctly, even after I added the dichlor last night, the spa continued to use that additional I added immediately after getting out to continue to clean the spa. Is that right? I added another .5 oz at 7a this morning and the FC is around 6 and has held pretty steady till know, 11:30am.

7am
pH-7.7
TA-60

Still looking good right? I am up to 19.2 CYA.

Thanks for the guidance!
 

JVTrain

TFP Expert
Feb 3, 2014
5,081
Central Minnesota
Looking good. Whenever I've used the tub, especially if it's more than one person, I target 10 ppm for dosage after a soak. I'll sometimes check the FC after 20 minutes or so (if I have time) and see if it needs a bit more.

Once you hit a calculated 30 ppm CYA, switch over to bleach. I like 6 to 8.25% bleach (regular laundry stuff) for the spa as it's easier to dose. I have 12.5% for the pool, but because it's more concentrated, it's a little trickier to do the smaller volume dosages.
 

cpd5215

Bronze Supporter
Jul 2, 2016
44
Columbus/OH
Alrighty! Todays the big day! LOL I added the last dichlor to the tub. With my calculated dichlor additions, I should be around 31.2 CYA. I tested CYA with test strips and it seems to be around the very low end of the 30-50 ppm on the strip so I think I am good. I have a CYA section on my bromine test tub in the Taylor 2106 kit, but I cant figure out how to test CYA yet. Anyways, my numbers this morning prior to adding the remaining dichlor were:
pH-7.3
TA-60
FC-3
and after addition of the remaining dichlor(test about 20 mins later)
pH-7.5
TA-60
FC-6.5
CH-125
CYA-31.2ish

It looks like the CSI is -.35, which from my understanding is ok. So I plan to switch over to Chlorox 8.25% bleach today. With that said, I have noticed during adding dichlor during this beginning process that the dichlor does lower the pH, but after running the jets(aeration), the pH seems to bounce back up. Is this normal? Also, from what you all have said, now that I will be adding bleach only, the pH should be more stable right? I will monitor the water after addition of some bleach tonight and see where I am at.

Thanks again for all your help! Spa ownership is much more fun now!!
 

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cpd5215

Bronze Supporter
Jul 2, 2016
44
Columbus/OH
Yes, dichlor lowers PH and aerations raises PH. PH will be more stable with TA at 60. As you add more MA to lower PH it will continue to drop a little more. Nice work! :thumleft:

Check this out sometime, :) CLICK HERE to Become a TroubleFreePool.com Supporter!!

Thanks a lot! I could not have done it without your guys detailed help. Once I understood the basic chemistry from this site and you guys, the process was much easier. In regards to MA, do I just add that if my pH drifts too high? I just watch my CSI and if that's good I should be set correct?
 

pooldv

TFP Expert
Platinum Supporter
LifeTime Supporter
Moderator Emeritus
Aug 10, 2012
25,412
FL panhandle
Yes, for your tub any CSI from 0.3 down to anything negative is good. Add a little MA when PH gets to 8.0 to lower it back to 7.6.
 

cpd5215

Bronze Supporter
Jul 2, 2016
44
Columbus/OH
Perfect! I will also check out that link! A modest investment is well worth all the savings you guys have brought me!


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JVTrain

TFP Expert
Feb 3, 2014
5,081
Central Minnesota
And to be honest, CSI doesn't matter very much in a fiberglass spa. As long as you maintain your pH and chlorine sanitation, not much else to worry about. Just keep and eye on TA and elevate it just a little if it goes below 50 ppm. Plain old baking soda from the grocery store (sodium bicarbonate) to raise TA if you ever get to that point.
 

cpd5215

Bronze Supporter
Jul 2, 2016
44
Columbus/OH
And to be honest, CSI doesn't matter very much in a fiberglass spa. As long as you maintain your pH and chlorine sanitation, not much else to worry about. Just keep and eye on TA and elevate it just a little if it goes below 50 ppm. Plain old baking soda from the grocery store (sodium bicarbonate) to raise TA if you ever get to that point.

Gotcha. Thanks for the advice. I will start adding bleach today and see how things go!


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cpd5215

Bronze Supporter
Jul 2, 2016
44
Columbus/OH
Hey guys. Just wanted to update you on how things are going. My pH has been staying 7.5-7.7 with TA at 60. Pretty solid. Water is crystal clear and still same shade of blue. My one concern is FC. I have been adding bleach keeping levels between 3-6 but I can't seem to keep chlorine in the spa. Remember, I added Ahh-some, drained and then started dichlor/bleach method. In two consecutive nights I have had my FC at 6 at 8pm and 12 hrs later it's around 1. Spa is 100 degrees and covered all day. What gives?? I am super excited with this method but I know I shouldn't be loosing all that FC.

Any help is much appreciated!


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cpd5215

Bronze Supporter
Jul 2, 2016
44
Columbus/OH
Is that with or without soaking in the tub?

Just me in the tub last night for 1/2 hr and then added to get me to 6FC. Today I forgot to mention I shocked to 10ppm at 8 AM and at 8 PM it is 6.5. Nobody was in the tub at all today


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JVTrain

TFP Expert
Feb 3, 2014
5,081
Central Minnesota
That 1.5 FC doesn't sound too bad for 12 hours in a 100 degree hot tub. The overnight could have still been residual bather waste. I'd target 10 ppm after soaks.

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cpd5215

Bronze Supporter
Jul 2, 2016
44
Columbus/OH
That 1.5 FC doesn't sound too bad for 12 hours in a 100 degree hot tub. The overnight could have still been residual bather waste. I'd target 10 ppm after soaks.

Sent from mobile device. Beware of brevity and spelling errors!

1.5 FC?? Am I missing a conversion factor somewhere. My 12hr period today was 8a-8p and I went from 10 to 6ppm. Am I confused?


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