Chlorine Level in Spa

[mrcooper]

Hi Folks,

Happy New Year! Hope you are all well. I have a question about the Chlorine Level or rather lack of in my spa.
With my old spa which was the same size 84 x 84 every second use or so ( I use it every night..... only me ) I'd throw in roughly a 1/3 cup of liquid shock. Generally the water stayed clear and I could smell the chlorine. I wanted to pay a little more attention to the new spa's water chemistry so I've been checking all levels.....Chlor, PH, Alk, Hardness and CYA. Every night I throw in 5oz of liquid shock..... the next day I have a zero level and can't smell a thing. Everything is on point but my CYA.....it's 100 or over due to the powdered shock I used for the first 2 or 3 weeks when I first filled it. The spa has one of those yellow frog type things and my dealer told me because of that I would have to use a very low amount of chlorine. One more thing is when I open the cover the water it pretty clear, once I turn the jets on the water gets a little grayish.
Am I just not putting enough Chlorine in? Thanks for your help! BTW the spa is a saratoga special edition

 

[jseyfert3]

Is that the Frog @ease system or something else?

What are you using to measure the water perimeters?

 

[mrcooper]

Good Morning....thanks for your reply. The filter stick is actually this one: Amazon.com: Zodiac W20750 Nature2 SPA Stick Mineral Sanitizer: Garden & Outdoor
I'm using a Taylor 2006 test kit. I've owned above ground pools for over 35 years and have always been able to keep the water right, these days using the BBB method. I've also had 3 different spa's over the last 35 years but never checked anything but chlorine. I figured it's a new spa and I'd try to keep it spot on.........much harder than the pool. Thanks for any help you can offer

 

[Mdragger88]

The stick is a waste of $ on a magic pill - you can continue to use it if u wish but make no mistake- you will have trouble if you don’t chlorinate properly according to the FC/CYA Levels as well as dosing high enough to make up for bather waste as u have seen. This applies whether u use the stick or not.
Since you have been likely under sanitizing due to your high cya I would do an ahhsome purge, drain & refill. Then proceed w/ the dichlor then bleach method (which means u only use dichlor until u reach 30ppm calculated cya then u switch to bleach)
Its all here in this guide it’s also a sticky @ the top of this forum

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...

www.troublefreepool.com

New spas often have biofilms left over from factory testing. The purge should not be overlooked.

 

[jseyfert3]

I’m not too familiar with the Nature 2 system. TFP doesn’t generally recommend the use of minerals.

My initial impression was in the case of your previous spa you didn’t have enough chlorine in the spa. My experience has indicated added every other use would not be sufficient to continuously maintain an appropriate level of chlorine.

Your CYA is too high, TFP recommends 20-30 or so to buffer chlorine harshness and follow the FC/CYA chart. You’ll need to do at least a partial drain and refill to get that back down.

Have you done an Ahh-Some purge on the spa?

And what do you mean the water is grayish when the jets are on? Do you have a picture?

 

[mrcooper]

Thank you for all this info guys! Would this be the proper product for the purge? https://www.amazon.com/Ahh-Some-Cle...hh-some&qid=1610205848&sr=8-5&tag=googhydr-20 That's a great read and I will follow those directions. If I remember correctly my CYA shot up to 100 in no time.... week or so. I will order the ahh some as soon as you confirm and I'll report back how I am doing going forward. I don't have a picture of the grayish water but could take one. The spa is clear when I open the cover but once the jets come on the water gets dark. Thank you both!

 

[jseyfert3]

Thank you for all this info guys! Would this be the proper product for the purge? https://www.amazon.com/Ahh-Some-Cle...hh-some&qid=1610205848&sr=8-5&tag=googhydr-20 That's a great read and I will follow those directions.

Yes that's what we recommend. Results may vary, you may not get a lot the first time you purge but when I inherited a used hot tub I got a LOT of junk out. Here's that purge: 26' Intex - Planning, Install, Upgrades, and Landscaping Thread

If I remember correctly my CYA shot up to 100 in no time.... week or so.

Each 10 ppm of FC added via dichlor adds 9 ppm of CYA.

I don't have a picture of the grayish water but could take one. The spa is clear when I open the cover but once the jets come on the water gets dark.

A picture would be good. You can easily attach them to a post here.

 

[mrcooper]

OK reporting back on this. Turns out my neigbor is a fan of ahhsome and had some for me to use. Refilled the tub, started it up with Dichlor. Two applications of 5 oz Dichlor and my CYA is already up to 40! Other numbers are FC 17, PH little high at 7.8, ALK 60 CH 60. If I continue to raise CF with Dichlor my CYA will be too high. Can I stop now and move to liquid clorine? I'm Using Liq pool shock which I believe is 12%. I'll hold until I hear back. Thanks!

 

[jseyfert3]

PH little high at 7.8

pH is good. I don't recommend you try and lower that until it reaches 8.0

Two applications of 5 oz Dichlor and my CYA is already up to 40!

5 oz!? How many gallons is your hot tub? 5 oz of dichlor will add 46 ppm of FC in a 450 gallon hot tub! It would also add 42 ppm of CYA in the same size tub.

If I continue to raise CF with Dichlor my CYA will be too high. Can I stop now and move to liquid clorine? I'm Using Liq pool shock which I believe is 12%.

Yes, that's exactly what you should do. The only reason to use dichlor is if you need to add some CYA. Too much use will quickly lead to too much CYA, as you've discovered. An alternative is to use CYA to raise the CYA levels rather than dichlor, and use liquid chlorine from the start. Since I have CYA for my pool this is exactly what I do now, I find it easier than adding dichlor and tracking CYA.

You will need to check CYA occasionally, it breaks down over time.

 

[mrcooper]

OK on PH

The Tub is 425 gallons

Oh boy.....I guess I didn't understand the Dichlor formula. Well I guess I don't have to worry and will go right into the liquid shock. I take it it is unsafe to go in it at 16 CF? If so if I leave it open and run the jets / air how long will it take to drop?
Thanks for your help

 

[jseyfert3]

The Tub is 425 gallons

Oh boy.....I guess I didn't understand the Dichlor formula. Well I guess I don't have to worry and will go right into the liquid shock. I take it it is unsafe to go in it at 16 CF? If so if I leave it open and run the jets / air how long will it take to drop?
Thanks for your help

5 oz of dichlor will add 49 ppm FC and 42 ppm CYA in 425 gallons. If you’ve added 10 oz that’s 82 ppm of CYA. I know you previously said you measured at 40, did you let the sample cool to room temp before testing? Testing that at spa temps will lead to a false reading.

Out of curiosity what formula were you using for dichlor additions? My above screenshot is from my phone, from the TFP PoolMath app. This is offered for Android or iOS, both free and paid subscription versions are available. There’s also the older, web based version that can still be used.

Related to this and your original post, 5 oz of 12% will add 11 ppm of FC. After a heavy usage it is entirely possible to add 11 ppm of FC and have no, or almost no FC the following morning.

I take it it is unsafe to go in it at 16 CF?

I assume you mean FC. It is safe to enter with a FC as high as the SLAM level, which for a CYA of 40 is 16. So if the CYA is 40 or above it’s safe to enter at a FC of 16. Chlorine / CYA Chart - Trouble Free Pool

 

[mrcooper]

Well.... I'm learning some stuff here. I was using the word formula loosley....I guess I figured 5oz of 12% was the same as 5oz of Dichlor. I don't have a smart phone. If you have a link to the web based version that would be great. And no.... I tested the water right out of the spa. I will test again at room temp tonight. Wow....this much tougher than balancing the pool.... Arrrggg Thanks again

 

[mknauss]

If you have a link to the web based version that would be great.

PoolMath

Discover the calculator behind the perfect pool, PoolMath. Dealing with pools has allowed TFP to become the original authors of the best calculator on the net.

www.troublefreepool.com

Look at the bottom of this page.

 

[mrcooper]

Thank you Marty!

 

[mrcooper]

Jseyfrt3.... I retested my CYA and it's 50 and my FC is 12. So I will work at maintaining my FC at 6-8. Once a week a SLAM.
Thanks again

 

[jseyfert3]

No problem, good luck and let us know if you have any additional questions!

P.S. I love my Saltron Mini SWCG, adds chlorine so what I have to add is greatly reduced.