Jump to content

Hot tub chemistry challenge


Recommended Posts

I have a 400gal hot tub with cover in socal.  It runs to maintain 103deg. I have had it for 1 month. I generally have to add pH increaser once every other week. I shock once a week with non-chlorine shock oxidizer but it does not seem to do much to increase free chlorine. I add dichlor every other day, sometimes every day when the spa is often used.  The problem is Cyanuric acid increases everytime I add dichlor and I have to replace 50% of water every month when Cyanuric acid is above 100 to keep Cyanuric acid level under 50.  What can I do to reduce maintenance time I’ve been spending on my spa?  Even if a service comes once a week that is not enough to keep clorine balanced. Any advice would be appreciated.


Link to comment
Share on other sites

I personally cannot tolerate the smell of bromine so that would be a no go for me.  I use the Frog @ease system in my hot tub and I am generally happy with it.  

Frog @ease doesn’t add cyanuric acid which is nice.  Having sold the system for 4 years and using it personally in my hot tub I have noticed that pH and Alkalinity tend to drift downward.  I usually have to add alkalinity increased every 2-3 weeks in my hot tub.  I do treat for phosphates when I fill my hot tub and I do add a weekly enzyme.  Otherwise I shock once a month with MPS. I have a 230 gallon hot tub that typically gets used daily by myself and 2-3 times a week by the rest of my family.

Outside of the monthly partial drain you have been doing, everything else is just basic water care and if you’re hot tub is getting used regularly I’m not sure how much less maintenance you can have.

  • Like 2
Link to comment
Share on other sites

Thank you both. My spa manual says do not use liquid chlorine or chlorine tablets.  I was thinking to switch to Calcium hypochlorite when cya reaches 30ppm.  I have heard the floating frog@ease unit gets sucked into the weir, but it sounds like there are possible frog@ease product that do not float.  Thanks again!

Link to comment
Share on other sites


They say that because it's a liquid you can easily spill and bleach the wood or plastic parts if poured directly on them. Run your jets and pour into the middle of the spa, not near the edge, and you will be fine.

Calcium hypochlorite increases calcium (obviously) and dissolves slowly so is more likely to damage your tub if added as a granule. If you read the instructions on cal-hypo you will find that you should mix it in a bucket of water until dissolved the pour that liquid in. 

There are several threads I have read about that @ease, smartchlor stuff and testing issues. I don't know much about it, but wouldn't even consider it in my tub.

Maybe @waterbearknows about it.

Link to comment
Share on other sites

2 hours ago, Sdivad.artt said:

Calcium hypochlorite when cya reaches 30ppm

this will increase calcium hardness and create its own set of problems. I would strongly recommend bleach since it does not have any side effects and is net pH neutral on use (alkaline when added, acidic when it is consumed) Trichor is very net acidic with a very low pH which is why it is not recommended for spas.

As far as FROG@ease goes., the chlorine source is an organic chlorine stabilized with dimethylhydantoin (same as bromine tablets). It won't raise CYA but it will still bind chlorine in a similar way as DMHD builds up in the water. However, it does not protect chlorine as strongly as CYA from UV so it probably does not bind as tightly.

My main problem with FROG@ease is that it is a silver/chlorine system and I am not a fan of silver and low FC levels. It is also expen$ive when compared to a chlorine only system using dichlor/bleach.

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...