Rainbow Chlorinator Tips and Tricks: Maintenance Made Simple

One wrong move with a tablet chlorinator can leave you coughing, gagging, and wondering what just hit you. We break down the Pentair Rainbow Chlorinator from a pool service pro’s point of view, including the safety habits that matter most when you open the lid and discover trichlor tablets that never fully dissolved.

We talk through the two common setups you’ll see on equipment pads: the offline Pentair Rainbow 300 series with black tubing and the inline Rainbow 320 series plumbed into the return line. You’ll learn how each style behaves, why placement after the heater is non-negotiable, and how small issues like trapped air or residue under a screen can turn into poor chlorine output and nasty fumes. We also get very clear on the biggest chemical compatibility rule in pool maintenance: these feeders are for trichlor tablets only. Cal-hypo in a trichlor chlorinator, or mixing residue between them, can create a dangerous reaction.

From there, we go hands-on with the fixes that keep these units running for the long haul: the offline check valve elbow that clogs and stops flow (and why replacing it beats trying to clean it), the stuck lid caused by a swollen O-ring, and the tools and lube that make servicing safer and faster. 

• why the Rainbow chlorinator is a practical choice for pool service work
• why trichlor tablets only and why cal-hypo can cause an explosion
• offline 300 series vs inline 320 series and what tends to fail on each
• correct chlorinator placement after the heater to prevent corrosion damage
• how to open the lid safely and avoid toxic fumes when tablets are undissolved
• the offline check valve elbow as the main clog point and the R172061 replacement
• how to purge air on inline units and clean the bottom screen
• stuck lid causes, swollen O-ring diagnosis, and the R172009 replacement
• using large channel locks and lube to remove and prevent seized lids
• black tubing brittleness, leak risk, and replacing both lines with R172023
• stocking a rebuild kit R172064 and other spares to avoid being stuck mid-route

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Transcript

Why Rainbow Dominates

Trichlor Only And Explosion Risk

Offline Vs Inline Models

Correct Placement After The Heater

Toxic Fumes And Safe Opening

Offline Check Valve Fix

Inline Air Purge And Screen

Stuck Lid And Swollen O-Ring

Brittle Tubing And Leak Risk

Stocking Parts And Final Tips

SPEAKER_00 1:02

And welcome to the Foog Way Podcast Show. In this episode, I'm gonna go over the Rainbow Chlorinator by Pentair. It's been a while since I've done a specific podcast on these chlorinators. These are probably the most familiar chlorinators out there. There are some other ones, but the Pentair ones seem to dominate the market, at least in my area of Southern California. Are you a pool service pro looking to take your business to the next level? Join the Pool Guy Coaching Program. Get expert advice, business tips, exclusive content, and get direct support. For me, I'm a 35-year veteran in the industry. Whether you're starting out or scaling up, I've got the tools to help you succeed. Learn more at swimmingpoollearning.com. I like the rainbow chlorinators, and if I was going to put in a chlorinator, I would go with the rainbow chlorinator over the other brands. The Hayward one is okay, but there are a lot of kind of negative things about it. First of all, it's gigantic inside there, and there's really no way to open those up without the toxic fumes permeating the area. And I'll touch on these fumes in a minute here as well. And also, it's hard to change those tubings in the Hayward chlorinator and set those, get those in there correctly. I found I have difficulty with that. And sometimes the lid on the Hayward chlorinator gets jammed on there to where you can't get it off. There's no easy way to get that off. Unlike the rainbow chlorinator, where the lid is stuck, there's an easy way to get it off of that chlorinator. So the rainbow chlorinator is by far, I think, the superior chlorinator, trichloro chlorinator, I should say, on the market today. And I should emphasize that these chlorinators are only for trichlor tablets and not calhypo tablets. It won't work with a cal hypo tablet. Even if you put a new rainbow chlorinator in, brand new, because you don't want to mix trichlor and calhypo, it causes an explosion. It will happen. Even if you had a brand new rainbow chlorinator and you use cal hypo tablets in there, there's not enough water flowing through there and over the tablets, the cal hypo tablets to dissolve them. So you don't want to use a trichlor chlorinator with calhypo tablets. You don't want to use an old trichlor chlorinator with cal hypo tablets because the residue in there will cause that to explode basically. And you want to make sure you only use trichlor tablets in the trichlor chlorinators. Now with that said, the rainbow chlorinators, they were their own brand at one point, but then Penthair, like everything, bought the rainbow chlorinator brand, put the word Pentair on there, and so now they're the Penthair Rainbow Chlorinator. Not sure why they kept the original name. Maybe there was something in the contract, they have to keep the name of the prior company, or maybe it was just brand familiarization. But the rainbow chlorinators have been around for a long time, and there are two types. There's the offline, which is the 300 series with the black tubing, and these come in various sizes, and then there are the inline chlorinators, the 320 chlorinators that actually are plumbed in to the plumbing. Which one do I prefer? I really don't prefer one over the other. I find that the ones that are on the plumbing seem to have less trouble, and those are pretty good chlorinators as well. The only problem you're gonna have with the 320 is that sometimes there'll be some chlorine tablets residue that gets underneath the screen on the bottom. You just have to take the screen out and kind of clean that area down there. But I do like the offline chlorinators as well, and they're they seem to be much more popular than the inline chlorinators because the inline ones that are on the plumbing usually are installed with the builder or at the build. And most pool pros don't put those on afterwards because it's really easy to plumb in the offline ones with the black tubing. One thing you have to be aware of is the location of the chlorinator. It should be after the heater, after the return lines, because you don't want that corrosive acidic trichlor getting into the heater. So make sure if you're installing it, you follow the directions carefully and you install it in the right location. I'll start with the number one problem you're gonna have with these chlorinators is that you open them up and the tablets are not fully dissolved. There's a couple things that happen when you do this. The first thing that happens is that a toxic fume will emit from the chlorinator itself that can be overpowering and could knock you out basically. It's gonna make you cough and gag and feel like you're you can't get your breath because you can't, because basically those fumes are very similar to the mustard gas that they use in World War One to gas all the soldiers. You can't catch your breath, you have to step away, and you're kind of like just heaving, it's really bad. And the the thing that is so bad about it is that it's happened to me many times, and of course I've learned over the years this lesson that when I get to a new account, even my own old account, I can't be careless around these chlorinators, and the reason why I get these fumes and I I get you know I get gas basically is because I'm careless at that moment, maybe busy, in a rush, not thinking, or maybe it's a Monday and I'm just not focused. Open up the lid of the chlorinator and I'll be standing directly over it. Very bad idea. So what I suggest you do, even if you know the chlorinator is probably good, is open the lid from as far as your arms can reach, put the lid somewhere like on the heater, and then step away for a minute. Don't go directly over it, don't do like a sniff test to see if it's okay. Just back away, do something else for 30 seconds or a minute, and then you're gonna hear the gurgling. That's the that's the air going into the line, and then look over the top because once you give it about a minute to air out, you can actually look in there and all the water drains out of there, of course, and so it's not quite as toxic as when you open it. The tablet's undissolved, and there's still water in there, and then there's an air gap in there, that's where all the toxicity comes from. Once the water gets out of there, you look in there and you see some undissolved tablets, maybe a stack of three of them that haven't been dissolved properly, they're maybe half dissolved. That's what's causing this problem. I would quickly put the lid back on, and then the number one problem with the offline chlorinator, if that's happening to you, that's the one with the black tubing, is that there's a little check valve on the bottom, it's an elbow. There's like a little BB in there basically. Now, Penter had told me many years ago, oh, you can clean those out in an acid and you can reuse those. I've never been successful in cleaning out the elbows. I just throw them away and put a new one on. So I carry several of these in my truck. And for your reference, these are the R172061 feed check valve 90 degree. They're not super expensive, and you can stock up on them. And they're good for all of the Pentair offline coordinators. What is it? The 300, the 302, the 300-19, and the 300-29. This is the main thing that gets clogged up with the uh trichlor residue, and that stops that check valve BB from moving in there, and of course, that causes the tablets not to dissolve and it causes the buildup of the fumes. You don't really have this problem with the inline chlorinators that are on the plumbing because they technically don't have that check valve elbow. And so the main problem with the inline ones is that the when you put it when you put the tablets in, what you want to do with the inline ones to prevent this from happening or any air being trapped in there. What I like to do is I turn on the system and then I'll leave the lid off the chlorinator. I'll turn on the system, it's the water fills up all the way, then I'll put the lid on it, and that seems to get rid of all the air that's in the inline chlorinators, and that solves the problem usually of those tablets not resolving in that one. And I'll also check the bottom again. There's a screen there. Take that out with a pair of you know oven tongs that you can get and see if there's any residue in there that you can get out that may be clogging up the bottom of the inline chlorinators. But for the offline chlorinators, that check valve elbow is the culprit. That's what's stopping those tablets from dissolving, and that's a big problem. It's easy to replace. Flip them over, uh turn off the pool, put the lid back on the chlorinator, flip over the 300 chlorinator, and then on the bottom, unscrew the black tubing. Of course, check for black widows, they love living underneath there in that little area, and unscrew the tubing. Sometimes the tubing is cracked, so you have to trim it back a little bit, and then put that back on. You just thread the elbow in and then put the tubing back on, and you're good to go. The second most common problem you're gonna have with these rainbow chlorinators is that you can't get the lid off. It's like it's glued on there. You're like, what's going on here? I can't get this lid off thing on this thing, I need to put tablets in here. Usually it's an older unit, and the problem is that the O-ring has expanded from the basically the chemical reaction with the fumes in there and the trichlor, and it's gotten really fat. I mean, it's gigantic. It's like it swells up to like 10 times the size of the regular O-ring. When you're going to get a replacement o-ring, they're gonna give it to you at the counter, and you're gonna see this little thin tiny O-ring. You're like, that can't be the same O-ring, man. The O-ring that I have on this thing is like gigantic. It's it is the same O-ring, it just swelled up to the point where it doesn't even look like the Rainbow 300 chlorinator O-ring. That part number is the R172009, and again, it's like really thin compared to what you're gonna pull off that chlorinator. Now, getting the lid off. Now, Panthere does make a tool, it has a white handle and like a piece of metal. I'm not a big fan of that tool. I guess it's okay, but I find like I sh I st I'm still straining myself a lot with that tool, it's not super effective, in my opinion. Probably needs to be longer, the handle, or something has to be changed on that. So, what I like using are my large channel locks, the blue handle channel locks that I use. These are the super large channel locks, and by the way, you should have a set of these on your truck. These are great for salt cell unions. Make sure you put a rag around the salt cell union, and you can usually get this off. You might need two pairs of channel locks, one to hold one side and one to grab the other side. But with the rag on there, you can easily get those salt cell unions off that are jammed on there. Your supplier usually carries these channel locks, they're the 16.5 inch tongue and groove slip joint pliers. And these are by channel locks, so that's why I call them channel locks, because that's the brand that makes them. But the actual, I guess, name of these are the 16.5 inch tongue and groove slip joint plier. So, why I like these large channel locks is because you can get that, you can get the blue end, the handle end, and you can actually stick it into the top of the rainbow chlorinator, and it's actually the perfect wedge for that. So put that in there, put one hand on the front of the channel locks, one hand on the back, and have it directly in the center of the rainbow chlorinator lid, and then put your weight on it, and it'll actually spin off like nothing. Even the tightest and most jammed lids will have no problem spinning off because I find these are the perfect size to get it on there and use your body weight to move that lid and get it off of the chlorinator much better than the little weapon kind of tool that Pinter makes for it. And another thing you can do is get a 2x4, put it inside those grooves, and you can actually turn it that way as well. Some guys do that, but I don't carry 2x4 in my truck, I just use my large channel locks and get that off. So when you get that off, make sure you have that O-ring or several of them in your truck to replace it. Now, if you're finding that it's getting hard to put on and off anyway, change that O-ring and top on top, and that should solve the problem. And usually you're gonna change these things every year or maybe sometimes less than a year, and so change those as soon as they start to inflate and get larger. I believe Pentar sells a lube for him, but you can use magic lube on him. I like magic lube for this, and just puts the magic lube on top and then put that lid on, and you should have no problems going forward, it should come off like butter at that point in the future. Sometimes you'll get to one of these offline chlorinators and it's not working, and it could just be because it was installed incorrectly. I've run into this one time where the inlet and outlet were not set right. Sometimes when you're messing with them too, like if you're taking them apart and changing the tubing, you'll mess it up and you'll put the inlet and outlet backwards. This happens as well. So be careful that when you're changing the black tubing, and I'll go over this in a second, that you do the inlet first, and then you do the outlet second. Don't take all the tubing off this thing and change it that way because you may get confused or you may not be paying attention. So the inlet should be after the filter, and then the outlet should be the last thing on the line. So just remember that if you're confused of which one is the outlet, the one on the bottom. That one, the bottom of the chlorinator is the outlet. The inlet is where the dial's at. The outlet is always the last thing after the heater. So that's the outlet tubing right there. So if you reverse it on accident because you weren't paying attention, or you get to a pool where it's installed incorrectly and already reversed, it's not going to work effectively that way. Just put the tubing on the correct way it's supposed to go. Now the tubing is the Achilles heel of this particular product because it's a black rubber tubing, and if the sun is hitting the equipment pad continuously all day long, that black tubing becomes very brittle and it tends to snap and break very easily. So if a gardener or someone hits the tubing or walks past it, or if a squirrel runs past it or something, that tubing will crack, and then the pool will actually drain down until it can't drain down any further. So if you have a float diverter valve on the skimmer, the black tubing breaks, it'll drain the water like until someone notices it, sometimes two feet below the skimmer. I've had this happen before when the customer calls and says, Hey, my pool is down like four feet of water. That's crazy. I get there and sure enough, the rainbow chlorinator tubing was broken, and the water is just shooting out all over by the equipment area, and this could be a potential big leak for you. So I always, when I get to a stop, I like to squeeze the black tubing every so often to see if it's getting brittle. You can see if it's getting brittle right away. If you squeeze it and it starts to start cracking your hands, or if it's a light color black, like a faded black color, then it's getting old right there. But if you squeeze it a little bit with your hand or pinch it, and if you see it start to crackle and start to kind of lose its consistency, then the tubing needs to be replaced. And I definitely replace that right away. Just carry a couple of six-foot tubing, extra tubing in your truck. I believe it's actually an eight-foot section, it's the R172023. So carry some eight-foot tubing in your truck, and this is a great way to replace the tubing when you need it. I always carry two of these because sometimes you're doing one and you might need it for the other. I also replace both, by the way, at the same time, the inlet and outlet. I don't just if the outlet looks cracking, looks like it's cracking. I don't replace just one of them, I replace both of them. One problem you may have too is that when you're putting the tubing on to whatever part of the plumbing, the little black kind of fitting, that may break as well. And then you're kind of in a world of hurt because you have to have those parts as well. Now they do sell a kit. Let me pull up the kit number. It's good to have the kit on your truck, by the way, because it does have those black connectors and the o-rings for those black connectors as well. The kit is the what is it? The R172064. It comes with everything you're gonna need to rebuild everything. It has the elbow, it has the little black connectors for the plumbing with the little O-rings, has the the valve here. It also comes with the silicone lube that I mentioned for the lid o-ring. I'm surprised it doesn't come with the lid o-ring, should have that in there. Maybe there's another kit. Let me see if there's a more robust kit that has that in there. I don't see that with the kit. That's interesting. I never noticed it wasn't in the kit. I always carry extra anyway. So the kit's good because it has all the parts you're gonna need. In case you have like a leaking o-ring as well, you could get your kit and get that O-ring out of it, just make sure you replace it later. But it's always good to have spare parts and then the kit as well. You also want to have a spare the valve that goes in front. I've broken those before many times just because they get old and brittle, and make sure you have extra parts for that. But they're these are really robust chlorinators, they're gonna last a very long time. All you really have to do is change parts on them all the time. And if you really do need to put a new body on the offline chlorinators, you can easily do that by leaving the plumbing the way it is and just changing the whole body. Sometimes a lot of gunk gets built up in there to a point where you really need to change out the whole chlorinator itself. And Penthair also said you can clean that with like nail polish remover, but I've never tried the clean one. I've just replaced it whenever they get old. It's not super expensive. But I find that if you just take care of these chlorinators, the offline chlorinators have a little bit more things to worry about than the inline chlorinators, the ones that are on the plumbing. If you take care of these and are vigilant, you can keep these things running for a very long time. If you're looking for other podcasts, you can find those by going to my website, soypoollearning.com, clicking on the podcast icon on the banner that'll bring up 1900 podcasts you're listening to. And if you're interested in the coaching program, you can learn more at PoolGuyCoaching.com. Thanks for listening to this podcast. Have a great rest of your week and God bless.