Peristaltic Pump Feeder for chlorine

Several of us are using the Stenner pump with the Stenner tank. Look here for more help

I've been using one of these $35 amazon specials for about a year and a half now to feed muriatic acid...

High Flow peristaltic Pump 12V Brushed dc Motor 400ml/min Kamoer KPHM400 lab Liquid dosing Pump​

https://www.amazon.com/gp/product/B09MS6C91D

that's wild... how long did your pump run each day? mine runs for only a minute, 5 times a week.

hmm... but with a peristaltic pump, the fluid never comes in contact with any pump parts... it's just pushed through the tube (works kind of like your intestines)

Yes for sure! When I made my acid doser I initially used tubing that was great for chlorine (base) but terrible for acids... I replaced it with some Tygon E-3603 and it's super flexible and has been working really well. I "think" the Tygon SE200 is great for chlorine, but I couldn't find the chemical compatibility sheet I'd seen before.

@ogdento - What kind of storage tank do you use? I need a 10-15 gallon tank for liquid chlorine, that would last a month for my pool.

Where in the plumbing do you attach the tygon tubing?

feel free to move this if it should be in a different thread...

my tank is 7-gallons, but I only need to squirt in a little acid each day. I got it from US Plastic: 7 Gallon Natural Molded Polyethylene Tamco® Tank with Lid - 13" L x 12" W x 13-1/2" Hgt. | U.S. Plastic Corp.

I attached the tubing to a connector I inserted into the input of the high pressure pump that used to run an old kreepy krauly. My VS pump still pushes water through this, so the injected acid flows through the pump impeller housing - probably eats away at it a little bit - and then flows out to the pool via the robot hose connection.

Here's my proof of concept... it's all now mounted in a cedar box about 10' from the pool:


Here's my tubing attachment point:


The pump is driven from a 12v ac adapter that's controlled by one of the Intellitouch aux relays, and programmed to run 5 or 6 days a week for 1 minute (I add an extra day or two as needed in summer). I forget exactly how much acid it dumps in (maybe a cup?) but it's enough to keep the ph right.

I've also got a pH sensor connected to a raspberry pi that texts me a reading every morning and afternoon - but the results aren't super reliable (the sensor is great but the sensor board isn't electrically isolated - I have an Orion A221 handheld pH meter that works great using the same sensor). As for the pi, I started with nodejs pool controller and relay equipment manager but had trouble with a custom pH driver I wrote, so just went for a simple daily text message.

I'm using two of these https://www.amazon.com/dp/B07N4LJF2R/ref=sspa_dk_detail_4 One with silicone tubing for Chlorine and one with Tygon E-3603 for acid. I kept having issues with the tubing and the acid so I diluted the acid with 4 gallons of water per gallon of acid and I pump 5 times as much liquid. It's all driven from a custom RasPi based system.

thrystan said:

I'm using two of these https://www.amazon.com/dp/B07N4LJF2R/ref=sspa_dk_detail_4 One with silicone tubing for Chlorine and one with Tygon E-3603 for acid. I kept having issues with the tubing and the acid so I diluted the acid with 4 gallons of water per gallon of acid and I pump 5 times as much liquid. It's all driven from a custom RasPi based system.

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Nice! Can you tell me more about the storage tanks you are using? I am having trouble finding the right fittings for the tubings, but I think they are available online at McMaster-Carr's website. Do you have any other source for those fittings that go from the 9-10mm tubings to a 1/2" or 3/4" PVC?

Are those some kind of sensors with blue and red caps on a bypass line between the pump and the filter?

norcalpool1 said:

Nice! Can you tell me more about the storage tanks you are using? I am having trouble finding the right fittings for the tubings, but I think they are available online at McMaster-Carr's website. Do you have any other source for those fittings that go from the 9-10mm tubings to a 1/2" or 3/4" PVC?

Are those some kind of sensors with blue and red caps on a bypass line between the pump and the filter?

Click to expand...

I believe I'm just using polypropylene fittings, they have good compatibility with both chlorine and muriatic acid. I bought some from McMaster, but I also bought some from Amazon, I don't recall which ones these are. This has been a work in progress for several years.

I bought the tanks off of Craigslist/Facebook Marketplace, I believe they are originally out of a car wash. I drilled a hole in the small caps and threaded the tubing through them. On the inside of the tank I'm using some glass tubing I found that the tubing fits on and holds the tubing to the bottom of the tanks. I purchased the warning lables off of Amazon. The Acid tank is a recent addition, before that I didn't worry about the warning labels since I knew what was in the chlorine tank and I wasn't worried about someone putting the wrong chemical in it if I needed to have someone fill it when I was gone. The sensors on the Chlorine tank are liquid level sensors, I have sensors at the 3, 6, 9, and 12 gallon levels. I'm also adding sensors to the Acid tank at the 5 and 10 gallon levels.

The red and blue sensors are Atlas Scientific PH and ORP probes, I use the EZO modules to interface them to the Ras Pi (btw when they say don't use perf board to connect to the EZO modules, they mean it). I'm not using either of the sensors to directly drive chemical feed, I check the PH and add as needed, and I use the ORP as a an indicator to tell me if I'm way off when I'm not able to be home, so for instance if I'm 900mv+ then I can probably reduce the chlorine I'm adding a bit and if I'm <600 I need to increase it some This is just for when I'm not home to do normal testing. I have a cron job that adds a fixed amount chlorine on an hourly basis, and I adjust the total by modifying that cron job. Last summer I had to be away from home for a couple of months and everything stayed sparkling, but when I got home I found I was higher than I wanted to be for chlorine, so I added the ORP probe. When I'm home I use the TFT test kit and adjust as needed, but that's difficult to do when I'm 1,000 miles away.

Other sensors in the picture are a flow meter, a pressure sensor, a water temp sensor, and a water level sensor. I'm expecting a PCB this weekend that will be replacing the perf board based system I am currently using. I'll also be upgrading from a Pi zero to a Pi Zero 2 which should allow me to install the current version of the nodejs poolController software. Once I get that installed I'll make a post with some more pictures, and a better description of what I've done.