Help balancing a holiday let hot tub (new water every 3-7 days!)

cowboycasey

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Jul 3, 2013
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Southern OK
when it comes down to it unless you have a concrete pool it matters way less.. I have only checked mine a couple times a year.. it does make a difference for CSI but you are emptying water every week..

Acceptable Minimum:​

0-50

Ideal:​

50-550

Acceptable Maximum:​

550-650
 

benseb

Member
Mar 23, 2021
21
UK
Sounds good thanks

I’ve got the hang of things now and can get nice readings with just 50g TA+ and 3g of chlorine

However I’ve only got Calcium Hypo as Chlorine which I’ve noticed makes the pH drift by about 0.6+ over a day. So after a bit of reading it seems DiChlor would be best to switch to (And no worries about CYA as frequently emptied)

as we could have 5 guests using the hot tub and with it being a holiday let people are in “party” mode, I was considering some MPS each morning to help tidy up from the night before and take the load off the Chlorine? That way hopefully the Chlorine I’m adding will keep more consistent rather than being used up quickly to oxidise the previous evenings use? Remember I can’t ask guests to handle chemicals

So adding some MPS each morning when we’ve got 4+ guests booked in alongside topping up with DiChlor?

I just want to keep the water as nice as possible for guests.
 

jseyfert3

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Keep in mind dichlor and MPS are both slightly acidic, so don't be suprised if MPS and dichlor use drag your pH down.

as we could have 5 guests using the hot tub and with it being a holiday let people are in “party” mode, I was considering some MPS each morning to help tidy up from the night before and take the load off the Chlorine? That way hopefully the Chlorine I’m adding will keep more consistent rather than being used up quickly to oxidise the previous evenings use? Remember I can’t ask guests to handle chemicals
Note MPS will show up on the DPD test unless the PoolLab has included an MPS interference remover. My understanding of MPS is the advantage is to oxidize waste before chlorine to help prevent the formation of CCs. With frequent dumping that seems unlikely to be an issue, so I'd give it a shot with cal-hypo or dichlor only first. Perhaps both, if you alternated cal-hypo with dichlor perhaps the pH rise you see with cal-hypo will be balanced by the pH reduction in dichlor?
 

benseb

Member
Mar 23, 2021
21
UK
Sounds good I’ll give it a go without first.

I like the idea of alternating. Will help me use up this tub for Cal Hypo too!

Thanks
 

benseb

Member
Mar 23, 2021
21
UK
Hi

As mentioned before, we have a holiday let and have just installed a Wood Burning hot tub. It gets emptied between guests, or once per week, whatever is sooner.

We use Dichlor as a sanitiser. I'm just getting used to testing and adjusting.

Now I'm using Dichlor (was Calcium Hypo before) the pH is nice and stable with TA around 50-60 (I tend to add 40g of TA+ on fill, so depends what the tap water is doing that day).

So I'm testing the water approx 10am and 5pm. Guests tend to use the hot tub in the evening, and sometimes in the afternoons if they have kids.

So I'll top up Dichlor until the FCl is between 3-5. However when I test in the morning, most often it's dropped to about 0.5ppm due to them using it overnight.

Should I worry about this period of it being <1ppm?

I'm not sure what I could do to keep the levels topped up after their use, as I can't really ask them to handle chemicals incase they do something stupid, especially as they'll probably have had a few 😂 . I've got some Trichlor tablets and a floater but was put off by them after reading people saying they will degrade your hottub fibreglass lining, especially if guests play with the dispensor and turn it "up", plus it was making the pH jump about.

Thanks
 

benseb

Member
Mar 23, 2021
21
UK
Hi all

Thanks for the help so far. So we’ve been running the hot tub for a couple of weeks now with guests.

keeping TA around 50-60
PH stays around 7.5

I’m still struggling to get the FCl right though. I’m testing in the AM and it’s nearly always 0.5ppm. I then dose it up to 5ppm. This drop is pretty much due to extended use the night before. Due to it being low there’s sometimes a bit of floating scum on the water surface that doesn’t look great, but generally the water is still clear.

Recently I changed slightly to having the trichlor puck in on low, then using DiChlor to top up. Hoping that this would top the levels up overnight, but they were still v low. I adjusted the TA up a bit to 80 to keep the pH stable when using trichlor.

So any ideas..? I can open the floater up a bit more I guess?
 

cowboycasey

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Southern OK
I think you are doing a great job at this.. You are in trial and error mode to figure out what works for you and your situation... As none of us do it that way...

As much as you change out water you can just about try anything and see if it works, I guarantee they will not know if something is amiss and the chlorine gets low :)
 
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benseb

Member
Mar 23, 2021
21
UK
Thank you!

And yes it certainly helps they won’t notice. It’s just be nice if there wasn’t hair etc floating in the mornings so I think I’ll try turning up the floater a bit more and see how it goes.

It’s quite good fun seeing guests use the tub. As it’s wood burning there’s trial and error there too. The current guests heated the water to 46c! Ouch!
 

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benseb

Member
Mar 23, 2021
21
UK
Any ideas what this is?

fresh fill yesterday so can’t be anything too bad. I’m thinking either ash from the burner or just soap scum? It wasn’t immediately visible but came up after having the bubbles on for a while.

very difficult to get rid of. Had to wrap our skimmer net in a pair of tights!

Also we had a family of 5 in. Overnight FCl dropped to 0.5. It’s taken me 40g DiChlor to get the reading up to 5.0.

Is this where MPS would be useful first to burn off the organic matter first, then add (less) DiChlor after?
 

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cowboycasey

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No Idea, It could be anything... One of the problems with so many people in it, they can do anything to it and you will never know what it is...

I was thinking about it, almost all hot tubs will be down to about .5 FC after a soak so unless they put a floater or something in after a soak that is just what it is going to be... :)
 
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Mdragger88

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Jun 1, 2018
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Hernando, Ms
Pool Size
26000
Surface
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Salt Water Generator
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Intex Krystal Clear
Any ideas what this is?

fresh fill yesterday so can’t be anything too bad. I’m thinking either ash from the burner or just soap scum? It wasn’t immediately visible but came up after having the bubbles on for a while.

very difficult to get rid of. Had to wrap our skimmer net in a pair of tights!

Also we had a family of 5 in. Overnight FCl dropped to 0.5. It’s taken me 40g DiChlor to get the reading up to 5.0.

Is this where MPS would be useful first to burn off the organic matter first, then add (less) DiChlor after?
I bet it’s fabric softener- this happens especially if people take a dip in their clothes cuz they forgot their suit. I had some in my tub yesterday as my son’s friend forgot his swimsuit. It was gone in a couple hours. At any rate shock level fc & filtering should take care of it. (Wash your filter out) Get u one of these to add to your tool box as well- very handy
CA2BA214-CAC8-45D4-91A6-B5C1E270B2C9.jpeg
 
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benseb

Member
Mar 23, 2021
21
UK
Nice one, I’ve found a net with a really fine mesh so will see how that works.

if it takes 40g of DiChlor to get the FCl back to 5ppm is that the best route or use non-chlorine shock first?
 

CrystalRiver

Well-known member
Jun 19, 2020
533
Massachusetts
When you top up at 5 PM, what FC are you targeting? You can go up to (just short of) SLAM level and it's still safe to soak in. Maybe targeting a higher level at 5 PM will help you to have more than 0.5 the next morning. If nothing else, it should mean there's less yuck hanging out when you get there at 10 AM, meaning it won't take as much added then to get it up to 5.
 
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benseb

Member
Mar 23, 2021
21
UK
I’ve been targetting 5ppm. Which is usually easy in the evening. Then in the morning targetting the same but it takes a whole lot more chlorine!

But yes good idea. What level could we have it at without it causing discomfort? I’m not sure if we are allowed to go over 5ppm due to the H&S guidelines with it being guests using it not us, will have to check.
 

jseyfert3

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Nice one, I’ve found a net with a really fine mesh so will see how that works.

if it takes 40g of DiChlor to get the FCl back to 5ppm is that the best route or use non-chlorine shock first?
The advantage of MPS would be less CC generation and lack of CYA buildup. With your weekly water changes it’s unlikely to be a big issue either way, but yes, lots of waste after a heavy use is exactly the situation where MPS can be useful.
 
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