How To Use a Pool Chlorinator


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This guide shows you how to recharge an automatic chlorine in-line feeder. Use caution when handling chlorine products and avoid breathing chlorine fumes.

Step by Step


Step 1

Your first step in refilling an automatic pool chlorinator is to turn off the pool pump. For maximum safety turn off the power at the circuit breaker to the pool pump.

Step 2

Turn the pool chlorinator control valve on the feeder to the OFF postion. and wait one minute to allow water and fumes to drain from the feeder

Step 3

Remove the pool chlorinator feeder cap by turning the cap counter-clockwise. When removing the cap, do not stand above the feeder and DO NOT INHALE the chlorine fumes rising from the open feeder. You may need a lever to help twist off the cap.

Step 4

Add two or three jumbo tablets to recharge the pool chlorinator feeder

Step 5

Lubricate the O-ring with a silicone lubricant and replace the pool chlorinator cap. Hand tighten only. Do not use a lever.

Step 6

Inspect line for kinks or wear each time the feeder is recharged. Replace line yearly if necessary.

Step 7

Turn the power to the pool pump back on.

Step 8

Reset the control valve dial to the level required to maintain 1-3 ppm of free and available chlorine in your pool. This will vary with pool use and weather conditions.


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 Posted: 12/13/2019 

Hello, First off, love your site! This is the first place I come to when trying to find out what is going on with my pool, thank you for all the help you have provided. I do have a question that I am unable to find anywhere on the internet so hoping you see this :) Right before my chlorinator, it splits into two separate return lines. One that gets diverted to my inline chlorinator and the other just straight into the ground. Both returns have shutoff valves right before going into the ground. Hope this helps provide the picture. My question is should I be shutting off one of the return valves? Such as keep the chlorinator one open if I am utilizing it and shut the other off OR should both of these be kept open and only half the water getting diverted to the chlorinator?

InyoPools Product Specialist  Posted: 1/3/2020 

Hello Jake - It sounds like someone split the line before the chlorinator in order to create a bypass. The bypass could be there because the pump provides too much flow for the chlorinator. A bypass allows some water to go through the chlorinator and the rest to go around it. I would keep both open and test the chlorine level after a couple of days. If the chlorine level is low and the tablets are not dissolving, start to partially close the line that bypasses the chlorinator.

 Posted: 7/19/2019 

Hello. If the black line coming from the chlorine dispenser is leaking is there a video you can suggest on how to fix or change? New pool owner =-) it's leaking directly below the dial you adjust from 1-5

InyoPools Product Specialist  Posted: 7/19/2019 

We do not have a video for replacing the tube, but it is a simple replacement nonetheless. The tube is held in place by a couple of plastic nuts, as you can see on the second page of this Rainbow Chlorinator In-Line manual. For a replacement black tube follow this link for the Rainbow Chlorinator Parts Diagram.

 Posted: 7/8/2019 

Do I fill the automatic chlorinator or just put in a few tablets?

InyoPools Product Specialist  Posted: 7/9/2019 

You can do it either way.

 Posted: 10/17/2018 

Hi, I work at a hotel. Our chlorinator runs, but for some reason our pool has been staying at 0 when we run tests to check the levels. Everything else is fine, but for some reason the chlorine just won't budge. The chlorinator has water in it, tablets dissolve, and the hoses aren't kinked. I'm not really sure what the problem could be?

InyoPools Product Specialist  Posted: 10/17/2018 

Hello Abbey - Your stabilizer may be too high. This can make it very hard to establish a good chlorine reading. Check out our article titled "Why Does My Pool Have No Chlorine".

 Posted: 7/18/2018 

The inline chlorine feeder would stay in place. You wouldn't remove that. If you have a floater in the pool, that can be removed by hand if you have young kids who may mess with it.

Anonymous  Posted: 7/18/2018 

So do you just take out the chlorinator with your hands before swimming or how do you remove it?

 Posted: 4/30/2018 

Every pool has a different chlorine demand. Warmer pools will go through more tablets. I would start with 3-4 tablets. If you notice that those dissolve quickly, add more. You want to replace the tablets before the old ones get down to small pieces.

Anonymous  Posted: 4/30/2018 

I have a 28,000 gallon pool with a DE filter running on a variable speed pump (most of the day the filter psi is around 9 1/2). My question is: how many tablets should I put in the chlorinator? (I have it set to 5). Thanks!

InyoPools Product Specialist  Posted: 8/21/2017 

Anonymous (Chlorinator) - Check that the black hose around the chlorinator is not kinked and that the dial is set to a value greater than one.

Anonymous  Posted: 8/19/2017 

Our chlorinator quit supplying chlorine to the pool. The water flows into the chlorinator but the pool has no chlorine. What should I check to find the problem?

Anonymous  Posted: 12/3/2018 

We have a Pentar Rainbow 320 in line chlorine feeder. The dispenser doesn’t fill with water when the pump turns on each day. I have to manually open the lid of the dispenser to allow it to fill. I’m finding if I don’t check everyday the chlorine level drops & I’m always adding liquid chlorine to boost it up. Very annoying when away on holiday

InyoPools Product Specialist  Posted: 12/6/2018 

It is normal to open the lid and let the Rainbow 320 fill when you first refill it with tablets. However, you shouldn't have to do this every morning. My guess is that you have an air leak on the suction side of the system. When the pump shuts off at night, that leak allows the water to drain from the chlorinator. Check out our guide titled "How to Identify and Correct Air Leaks".

InyoPools Product Specialist  Posted: 7/24/2017 

Christopher - Yes, three tablets will produce a higher concentration of chlorine in the tube than one tablet. The chlorinated water that you meter out will have more chlorine in it.

 Posted: 7/23/2017 

Does it make a difference in chlorine output, if you are only putting one tablet in the tube vs 3?

InyoPools Product Specialist  Posted: 7/20/2017 

Pool Girl - For a 25,000-gallon pool, I would start the chlorinator at a high setting then back off if your chlorine level gets too high. If you are getting algae at the bottom of your pool, you may have a water circulation problem. I would get a suction pool cleaner to help circulation on the lower levels. You might also look at getting a bigger pump and filter.

 Posted: 7/17/2017 

We just bought a house with a pool, so I am new to this. I am inquiring about the chlorinator. What should the chlorinator be set on for a 25,000 gallon in-ground pool? Also, what is the best product to coordinate with this to clear the algae that builds up on the bottom of the deep end?

InyoPools Product Specialist  Posted: 7/17/2017 

Leo - Try lubricating the o-ring and threads with a silicone lubricant.

 Posted: 7/14/2017 

Why is it so hard to remove the cap to my Hayward CL 110 Off Line Feeder when I add my chlorine (3 inch tablets) I need to have my wife hold the Feeder with Giant Channel-Locks and then I turn the lid with all my might to get the lid open. I don't like the fact that the base spins around. D. Leo Hall in Boise, Idaho.

InyoPools Product Specialist  Posted: 6/17/2017 

DFronz - No. The chlorinator only generates chlorine when water flows through it. The chlorinator should be the last unit in the return lines. Water does not flow through the return lines when it is in Baskwash mode or when the pump is off.

 Posted: 6/17/2017 

Should the chlorinator valve be set to closed when the pump is off? Or when I am backwashing?? Thanks

InyoPools Product Specialist  Posted: 6/4/2017 

Pam -Yes, you could use this chlorinator for an above ground pool but it is generally used with rigid pipe. You would need adaptors to go from the tubing out of your filter to the chlorinator and also from the chlorinator to the tubing going back to your pool.

InyoPools Product Specialist  Posted: 6/2/2017 

Anonymous (CL settings) - Position "6" releases the most chlorine.

 Posted: 6/2/2017 

Can this system be used for and 18x33 above ground pool??

Anonymous  Posted: 5/31/2017 

Number system 1 to 6 what number let's the most chlorine in 1 or 6?

InyoPools Product Specialist  Posted: 5/29/2017 

Anonymous (Chlorinator) - The chlorinator works at both speeds but only produces half the chlorine at half speed since you only have half the water flow. Check that the hose between the chlorinator and piping is not kinked. If you have a large pool, you could run the pump at half speed for a longer time or you could add another chlorinator in line with the first.

Anonymous  Posted: 5/26/2017 

Put in line unit is not providing enough chlorine to our pool. It is set to 5 and I have to shock weekly plus I added a floating chlorine dispenser. What is wrong. Have a dual speed pump. Does it only chlorininate on high soeed?

InyoPools Product Specialist  Posted: 5/10/2017 

Sandro - You have to turn off the pump to add tablets to the chlorinator. The water in the chlorinator is under high pressure when the pump is operating.

 Posted: 5/10/2017 

Can I open chlorinator and drop in tabs when pool filter is running or do I have to always turn filter off before this process? My pump loses prime when I turn filter on and off so I was wondering....

InyoPools Product Specialist  Posted: 11/10/2014 

Anne - The water normally flows out of the Chlorinator when it is opened up. You do not have to fill the tube. It will fill during normal operation.

 Posted: 11/7/2014 

Hello my pool guy lft the cap loose and the water level dropped I am tightening the cap and there is a chloride tablet in the tube but no water is this correct or should I add water to the tube.

InyoPools Product Specialist  Posted: 1/4/2014 

Steve Dondalski – The water should drain from the tube when you shut the control valve off. You may have a faulty control valve. Check that the hose coming off the control valve is not kinked.

 Posted: 12/30/2013 

When I set the chlorine level to the off position, turn off the filter and wait for the minute, the water level in the tube does not lower when I open the cap. Could the check value be malfunctioning? Or am I doing something wrong? Thanks for the help.

 Posted: 7/22/2013 

I have a 700 or 1400 aqua pure chlorinator system the panel reads service with no other lights on and an error message of 110 that is not listed in the owners manual with the other error codes. I am sure it is a salt cell corrosion error i need a "step by step" to clean the salt cell.

InyoPools Product Specialist  Posted: 6/21/2013 

Amber - If your chlorine level is continually low you may have to increase the chlorinator setting. Before you change the setting, however, make sure your pool is balanced. In particular make sure you pH and Stabilizer are within their ranges. If either of these are out of bounds, you will not be able to maintain proper chlorine level.

 Posted: 6/21/2013 

How do you know what speed to put it at? We have an 16x32 lazy L inground pool, and we just installed the chlorinator. We put it on 4 as recommended to start by the pool company and they said check back in a week to see if the 4-5 3" pucks were gone. I run the pump roughly 12 hours at night 7pm-7am (they recommended 24 hours would be best), and I am getting a low reading from test strips I use regarding the chlorine levels. Am I doing something incorrect or is this normal?

InyoPools Product Specialist  Posted: 1/20/2013 

raiha - If you install a salt chlorine generator, it will replace your chlorinator. However, you will still have to shock your pool with chlorine occasionally with heavy use.