By Rainbow Products



Part # R171016

Dimensions 20" L x 6" W x 6" D

Alternate Part #'s 42-196-1045, PENR171016

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 special 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:
11 Tablets
Small Tablet Capacity:
4.5 Lbs.
Treatment Capacity:
5,000-48,000 gal.

?     Asked on 6/20/2006by 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

?     Asked on 3/10/2007by 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 9/22/2008by 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 1/30/2012by 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 8/15/2012by 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.


Est. Repair Time

1 to 2 hrs

Tools Needed

Screwdriver, Pliers, Teflon tape

Existing Pentair 300 lasted 29 years.

Written on 7/8/2021 by Guest

What a team. Inyo and Pentair, all the instructions and plenty of parts to do the job right. I replaced everything and felt great about it. One note of dismay is the lousy metering valve. They never last more than a year or two. Now $20 per.
Couldn’t you come up with a MV that could withstand a little chemical abuse?

Were these instructions helpful? 


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.

Were these instructions helpful? 


Review Summary

 (Average 4.93  out of 5 stars)
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