Chlorine Automation

[bwilford]

I'm interested to find out if other people in this community have information about chlorine sensors or if they are interested in what I have done with my Jacuzzi J-375 hot tub to automate it.

I bought the Hot Tub in 2015 or 2016. The water used to last about 3-6 months, the pool service did not keep the levels right and I was running the pumps about 16-20 hours a day. Then I found out about TFT and started to maintain my own chemicals.

About a year ago, I decided to automate the Hot Tub control. I reverse engineered the electronics between the buttons and the control until. After that I installed a wi-fi based Raspberry-Pi computer and then I installed a peristaltic pump to add a little chlorine every day. Right now, I test chemical levels about once every 3-4 weeks. Generally I need to add di-chlor, to move the CYA levels back up and a little dry acid to move the pH down a bit. The system is very stable, I run the pumps about 2-3 hours a day and I only do that on cheap rate night electricity, which saves me about $75 a month on my electric bill. Basically I heat the hot tub to 105 or 106 in the morning and it's right about 103 when I want to go into it in the evening. I add about 50mL of chlorine a day, which is about 2 ppm in a 470 gallon hot tub. All the pump and chlorine scheduling is controlled by the Raspberry-Pi.

The current water is just over 2 years old, it has very high hardness levels (550) and is right on the edge of my ability to balance. I am about to dump and replace about half the water to get the hardness back down to a reasonable level. So I figure this means the water lasts about 4 years compared to the 3-6 months I used to get.

I started to write up a blog earlier this year which is at DIY: WiFi my Hot Tub. A lot of functionality has been added since I did that blog, which I have not written up yet.

Has anybody else out there built there own hot-tub controller, Do you measure the chlorine levels or just add some each day as I do. Is anybody out the adjusting pH automatically ?

Thanks to all those that have made this forum great and for providing the basis for me to have done this project.

Bruce

 

[tmm1]

Very cool!

I recently converted my spa to salt-water and am using the SmarterSpa system which has a chlorine monitor and kicks off the SWG when the chlorine levels fall below 1ppm. It works quite well, but I wish it was WiFi connected so I could record stats on how often it was running and when.

Hooking a rPi to the existing spa controls is a great idea. Do you know how similar the spa controller is across different spa makes and models?

 

[dunginhawk]

Very cool!

I recently converted my spa to salt-water and am using the SmarterSpa system which has a chlorine monitor and kicks off the SWG when the chlorine levels fall below 1ppm. It works quite well, but I wish it was WiFi connected so I could record stats on how often it was running and when.

Hooking a rPi to the existing spa controls is a great idea. Do you know how similar the spa controller is across different spa makes and models?

I have a tub with SWG that I only finally realized wouldn’t kick in until i got over about 2500/2600ppm salinity. Now I’m actively making plenty, more or less to keep it self maintained from a sanitizer standpoint. I think i may have added 2 oz of chlorine over the last 4-5 soaks.

I would love to be able automate things, to have WiFi enabled sensors of chlorine etc.. i hate having to do multiple drop tests per day as I manage this thing. Luckily that’s about the only thing i test, the rest using TFP is super stable

 

[bwilford]

Hi,

I'll have a look at the SmarterSpa system to see how it reads the chlorine levels.

> Do you know how similar the spa controller is across different spa makes & models ?

I don't really know as I have not taken any others apart. The Jacuzzi Hub I have uses a Sundance controller (I believe Sundance owns Jacuzzi) so I figure most of those are pretty similar in that I suspect they use a SPI serial interface. However, I bet the button codes and the information sent from the controller to the buttons for display (temperature for example) is a different format. I did start to pull my brother in laws Tub apart. His used a Balboa VS100 controller, which has a similar looking connection from the controller board to the buttons, so I guess it may be the same serial protocols, but I did not do an analysis yet, maybe sometime I will. Next time I try this, I'll use on of the Pi zeros, because they only cost $10.

Bruce