Rainbow 300 Offline Chlorinator - R171016



Part # R171016

By Rainbow Products

  4.93 Average  



Part # R171016

Dimensions 20" L x 6" W x 6" D

Product Description

The Pentair Rainbow 300 is a completely enclosed off line system ideal for existing pools where permanent installation into the return line is impractical. It top loads, requires no venting and lets you adjust the optimum chlorine/bromine feed rate for your pool. It operates on pressure side of pump. Spa chamber not included


  • Completely enclosed system- no sperical venting required
  • No escaping gas
  • 50 PSI maximum operating pressure
  • Retrofits into existing pools/spas
  • Uses 1/4 in. feeder hoses, control valves, and fittings.


  • Holds 11 large or 98 small tablets
  • Treats 12,000 to 48,000 gallons
  • Dimensions: 21 in. (H) x 7 in. (W) x 12 in. (D)
  • Service Clearance for Lid Removal: 22-1/4 in.


1 Year Warranty

* Note: Consult your local authority to determine their guidelines if needed. Results may vary due to pool/spa equipment and many other factors.

Product Specifications

Large Tab Capacity:
Small Tablet Capacity:

?     Asked on 8/10/2018 by

Can you use the chlorine sticks in this as well? If so how many? Thanks

A     Answered on 8/11/2018 by InyoPools Product Specialist Lennox H.

Hi. You're able to fit approximately 4-6 chlorine sticks in this chlorinator,

?     Asked on 2/20/2018 by John R Marihart

Are hoses included

A     Answered on 2/21/2018 by InyoPools Product Specialist Lennox H.

Hi, John. The hose and hardware are included. 

?     Asked on 1/13/2018 by Bruce

on the rainbow 300 on my pool the bottom fitting is from heater ihave a top fitting to pool do I have to drill hole for fitting

A     Answered on 1/15/2018 by InyoPools Product Specialist Lennox H.

Hi, Bruce. Yes, you will have to drill holes in the pvc for the fittings. 

?     Asked on 7/23/2017 by

I've noticed that the elbow check valve in the bottom of this unit frequently gets clogged with chlorine corrosion. This prevents the small ball bearing inside from moving and seems to prevent the chlorinated water from going to the pool. Is there any way to prevent this issue?

A     Answered on 7/25/2017 by InyoPools Product Specialist Lennox H.

Hi. Unfortunately, there is no way to prevent corrosion from occurring since chlorine is highly corrosive. The parts used in the chlorinator should not corrode because of the material is made out of. 

?     Asked on 7/7/2017 by

How is pH controlled when using this type of chlorinator?

A     Answered on 7/8/2017 by InyoPools Product Specialist Lennox H.

Hi. You can use a Commercial Pool Chemical Controller along with the Stenner Liquid Chemical Feeder

?     Asked on 6/17/2017 by Kevin

We are interested in installing the Rainbow offline unit in our 24K gal pool. Our plumbing (pump etc) was installed lower than the pool water line. Would we need a check valve if using the offline unit since it would be installed on plumbing lower then the pool waterline? Thanks!

A     Answered on 6/17/2017 by InyoPools Product Specialist Hector F.

Installing a check valve or two on the system in general would be a good idea in making service performed easier and safer.

?     Asked on 6/2/2017 by carol

Where do I buy the fittings for model 300? They were not in the box. Thanks!

A     Answered on 6/2/2017 by InyoPools Product Specialist Patrick P.

Here you can find the Fittings for the Rainbow 300 Chlorinator

?     Asked on 5/26/2017 by

is this unit complete with hoses clamps and valve

A     Answered on 5/26/2017 by InyoPools Product Specialist Patrick P.

Yes this Rainbow Off Line Chlorinator is complete with hoses clamps and valve

?     Asked on 2/10/2017 by Steve

How much 3/8" tubing does it come with?

A     Answered on 2/10/2017 by InyoPools Product Specialist Scott W.

Yes, the tubing and all the connections will come with the chlorinator.

?     Asked on 8/11/2016 by Amp electric

Does this chlorinator come with a screen inside ? Or do we just drop the 3 inch tablets in it? Mine did not come with an interior screen

A     Answered on 8/11/2016 by InyoPools Product Specialist Scott W.

The tabs are just dropped into the canister, a screen doesn't come with it.

?     Asked on 8/2/2016 by DoubleD

I cannot find the correct manual for this and I have one, what size drill bit is recommended to drill the holes into the PVC. Can you provide a link for the manual as well. Thanks.

A     Answered on 8/7/2016 by InyoPools Product Specialist Lennox H.

Hi DoubleD, A 3/8" hole is required for the installation of this unit, click link Rainbow 300 & 320 Chlorinator Owner's Manual for manual.

?     Asked on 6/28/2016 by ED

The base of the chlorinator is setting in pool room on concrete floor. Its hard to open. It has three holes in base. Is it ok to put a 24" by 24" plywood base and screw it down.

A     Answered on 6/28/2016 by InyoPools Product Specialist Alan M.

Yes, you can absolutely bolt this chlorinator down.

?     Asked on 3/1/2016 by Lee

Does this feeder come with all the hoses and fittings shown above?

A     Answered on 3/1/2016 by InyoPools Product Specialist Lennox H.

Hi Lee, The Rainbow 300 Offline Chlorinator does comes with hoses and fittings shown for installation.

?     Asked on 9/19/2015 by mark

looking for a feeder for a jacuzzi hot tub.

A     Answered on 9/23/2015 by InyoPools Product Specialist Lennox H.

Hi Mark, You can use the Rainbow 300 Offline Chlorinator on a Jacuzzi hot tub. You will have to follow the installation instructions to insure the tubes is placed in the correct position.

?     Asked on 8/20/2015 by John

It says to install on pressure side, would that mean I install it before my filter and heater, or on the return side after my heater?

A     Answered on 8/21/2015 by InyoPools Product Specialist Joe S.

You will want to install this after your equipment

?     Asked on 7/20/2015 by Rob

I currently am using a hayward offline chlorinator. I am lucky to get one season in before it starts leaking (usually the lid). I would like to try the 300. Are the thread fittings for the tubing the same size? Also, what kind of lube do you use to keep the lid easy on and off?

A     Answered on 7/22/2015 by InyoPools Product Specialist Lennox H.

Hi Rob, The tubing and fittings are different but the size hole drilled into the PVC will work.

?     Asked on 5/18/2015 by Pat

Is bottom the inlet or the outlet? Is the inlet on the side and the outlet on the bottom? Just bought one yesterday help!

A     Answered on 5/19/2015 by InyoPools Product Specialist Patrick P.

Yes the inlet would be coming in at the top of the base near the flow control and the outlet goes out through the bottom of the chlorinator.

?     Asked on 5/17/2015 by Stan

Which Hayward offline chloronator would match rainbow 300 offline in performance . Have the Rainbow want to replace it with Hayward . Looks easier to open .

A     Answered on 5/17/2015 by InyoPools Product Specialist Patrick P.

Hi Stan the comparable Hayward chlorinator would be the Hayward CL220 Offline Chlorinator we also carry a good Offline Chlorinator by Custom Molded Products.

?     Asked on 5/7/2015 by john

I've seen the Rainbow Offline chlorinator with a clear plastic chamber so you can see how much of the tablets are left. Do you sell the clear plastic chlorinator?

A     Answered on 5/8/2015 by InyoPools Product Specialist Patrick P.

Hi John, Yes we do carry the Clear Rainbow 300C Chlorinator here. We also carry an Off-line Chlorinator by Custom Molded Products W/ a Clear Glass Lid.

?     Asked on 5/7/2015 by Jeff

What is the best way to replace the 90 degree elbow on the bottom of the Rainbow offline 300 chlorinator, do you try to do it in place or remove the unit to work on.

A     Answered on 5/7/2015 by InyoPools Product Specialist Lennox H.

Jeff, You can remove the elbow from the unit with it in place or unscrew the tubes from the chlorinator and work on it.

?     Asked on 4/15/2015 by

What is the best way to keep the top lubricated for easy removal?

A     Answered on 4/15/2015 by InyoPools Product Specialist Lennox H.

Jack, Every time you're placing chlorine tabs into the chlorinator make sure you lubricate the o-ring and the threads on the cap.

?     Asked on 11/12/2014 by R. Shea

I'm having difficulty locating the pressure nuts for securing a 1/4" line to the outlets. Can I buy these seperately?

A     Answered on 11/13/2014 by InyoPools Product Specialist Robert M.

R. Shea - The compression nut for the control valve is part number 2114-25. The other compression nut is included with the tube fitting. That part number is 2114-08A.

?     Asked on 10/2/2014 by Guest

I have a variable speed pump and have been fine tuning the pump flow for my pool. What is the min psi / GPM required to run this?

A     Answered on 10/2/2014 by InyoPools Product Specialist Patrick P.

To properly assess the appropriate psi and gpm for any pool we would need more specifications on your system and pool. Such as pvc diameter, total hp and service factor of the motor , filter make and model. and if solar is present. General average for psi is betwenn 7 and about 17 psi on the filter gauge and gpm is generally between 65 to 90. Many variables though.

?     Asked on 8/15/2012 by Guest

Do all the necessary parts come with the Rainbow 300 Offline Chlorinator?

A     Answered on 8/15/2012 by InyoPools Product Specialist Patrick P.

Yes, the Rainbow 300 comes with all the parts needed for installation. It comes  with: the 1/4 in. feeder hoses, control valve and fittings.

?     Asked on 8/15/2012 by Guest

Is there a maximum distance the Rainbow 300 chlorinator can be from where it taps into the pool plumbing lines?

A     Answered on 8/15/2012 by InyoPools Product Specialist Patrick P.

Pentair does not mention a maximum distance but 8' of tubing is included with the chlorinator. We recommend that you contact Pentair directly for more information. Their technical support should be able to assist you. Their toll free number is 1-800-831-7133

?     Asked on 8/15/2012 by Guest

I have a 35,000 Gallon in ground pool. Will the Rainbow 300 handle this size pool or do I need to go with bigger unit?

A     Answered on 8/15/2012 by InyoPools Product Specialist Patrick P.

The Rainbow 300 chlorinator is good for pools 12-48k gallons, So, yes, this chlorinator is sufficient for your size pool.

?     Asked on 8/15/2012 by Guest

What size tablets does the Rainbow 300 Offline chlorinator take? And how tablets at one time?

A     Answered on 8/15/2012 by InyoPools Product Specialist Patrick P.

The Rainbow 300 chlorinator uses both 1" and 3" tablets. You will need (98) 1" tablets and (11) 3" tablets.

?     Asked on 8/15/2012 by Guest

I have a Rainbow 300 Offline chlorinator, but it doesn't have the smaller cylinder piece in the picture on your website. What is this used for?

A     Answered on 8/15/2012 by InyoPools Product Specialist Patrick P.

The long cylinder piece in the picture is an optional piece for 1" chlorine tablets.

?     Asked on 8/15/2012 by Guest

I looked at the Rainbow 300 Chlorinator diagram and did not see any valve that would automatically release chlorine gas build up in the canister. Is that correct?

A     Answered on 8/15/2012 by InyoPools Product Specialist Patrick P.

Yes, you are correct. There is not a valve to release off gas on the Rainbow 300 chlorinator and we are not aware of a chlorinator which has this feature. We have read through the different pool chlorinator manuals and they state that you want to always keep the pool return lines open to prevent gas build-up.

?     Asked on 1/30/2012 by Guest

What is the difference between an inline and offline chlorinator?

A     Answered on 1/30/2012 by InyoPools Product Specialist Patrick P.

An inline chlorinator would be plumbed directly inline with the plumbing.  For an existing pool, this would mean a section of pipe would need to be cut out to install the chlorinator.  An offline chlorinator attaches to existing plumbing by chlorinator tubing (holes would be drilled into existing pipe to attach the tubing.)

?     Asked on 9/22/2008 by Guest

Do the parts come with this unit?

A     Answered on 9/22/2008 by InyoPools Product Specialist Patrick P.

Yes this does come with the 1/4 in. feeder hoses, control valve and fittings.

?     Asked on 3/10/2007 by Guest

Is there a feedback mechanism that tells the unit the chlorine balance in the pool? Is this a way for me to automate addition of clorine to keep it always at the correct level? Or, just another place to put the tab aside from the the drain basket?

A     Answered on 3/10/2007 by InyoPools Product Specialist Patrick P.

There is a dial on this unit which has a setting from 1-10 If you set the dial on 1 it will be letting the least amount of chlorine to the pool and if you have it set at 10 this would send the most amount of chlorine to the pool. So you can automate the feed of chlorine to the pool but you will still need to manually test your water. We do not recommend placing tablets in the skimmer basket because this high concentration of chlorine goes directly back to your pump and can cause corrosion to your pool equipment. If you do not go with the automatic chlorinator we would recommend at least going with one of our floating chlorinators so you do not damage your equipment you may view our floating chlorinators here http://www.inyopools.com/chlorinators_floating.aspx 

?     Asked on 6/20/2006 by Guest

What kind of chlorine tablets do I use with this type of chlorinator? Do you sell them?

A     Answered on 6/20/2006 by InyoPools Product Specialist Patrick P.

You can use either 1" or 3" tablets. We sell both - here is a link to the chlorine tablets: http://www.inyopools.com/chemicals_sanitizers.aspx


Est. Repair Time

Less than 1 hr

Tools Needed

Screwdriver, Adjustable Wrench

Chlorinator replacement

Written on 10/24/2017 by Guest

This offline chlorinator was the brand and model originally installed when my pool was new. It lasted about 13 years and I replaced it with a different low quality product—you get what you pay for as that model failed within 2 years. I therefore went back to this proven model. Installation was simple and took well under an hour using a flat-head screwdriver, thread-sealing (“plumber’s) tape and an adjustable wrench. Just make sure you have the flow direction (inlet line and outlet line set properly before tightening up everything.

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