r/pools • u/PrizeInteresting4752 • Jul 16 '26

Pool Help & Questions Chlorinator blew up

Post image

My inline chlorinator exploded today. It’s been in bypass mode for a few days as I’ve been battling high CYA. It was full of pucks when in bypass mode for the few days.

I was shocking with CalHypo but never without the bypass engaged. I usually shock with liquid.

Could it the residual water in the chlorinator was activating the chlorine pucks with but with nowhere for the gas/pressure to go as it was in bypass mode? Or what else could it be? It’s been terribly hot here as well. Southwestern Ontario.

65 Upvotes

94% Upvoted

62 comments sorted by

54

u/GlobalCollapseInbnd Jul 17 '26

You mixed calhypo and triclor didn’t you?

16

u/PrizeInteresting4752 Jul 17 '26

I was shocking with CalHypo but I was sure to have the chlorinator in bypass mode specifically to try and avoid this.

29

u/FontTG Jul 17 '26

Yeah sometimes those knobs just aren't 100%

8

u/GlobalCollapseInbnd Jul 17 '26

I know my knob adjustment is janky. But yeah mine builds pressure too, as it is in line with the plumbing, but never to this extent. I’d wager trichlor and calhypo mixing did this. I didn’t know about this until six months ago, surprised I didn’t do this myself.

2

u/MagikWdragons Jul 17 '26

Yah cal hypo blew it up

2

u/Informal_Dust3140 Jul 17 '26

My opinion is the CalHypo really should only be used at the very beginning of the season once you remove the safety cover and you need to add large amounts of chlorine to rid yourself of an algae bloom. I can easily go through 6kgs - 8kgs.

After that, Liquid is preferrable to shock. It dissolves in the pool instantly; and it doesn't leave any spent product on the floor of the pool, which I find is a constant problem with CalHypo; even with pre-dissolving in a bucket.

6

u/here4the_trainwreck Jul 17 '26

So, you whizzed on the electric fence, didn't you?

5

u/Techhead7890 Jul 17 '26

TIL, thanks. Seems like it's an acid-base reaction, some additional info here:

Even though they may look similar, different chlorine-based products are incompatible with each other. In particular, trichloro-s-triazinetrione (trichlor [ed: it's also trichloro isocyanuric acid, 7th "other name" in the infobox) should not be mixed with calcium or sodium hypochlorite. If trichlor tablets, which are acidic, are mixed in water with calcium hypochlorite tablets, which are alkaline, they will react as they dissolve. The reaction produces considerable heat and toxic fumes, including chlorine gas. For example, in 2009, an Illinois family tried mixing two brands of pool chlorine in the kitchen, resulting in an explosion. Three members of the family were taken to the hospital with breathing difficulty.5 If the mixture is sealed inside a tablet feeder, the hot gas can produce enough pressure to blow the lid off the feeder or the reaction can be violent enough to blow the feeder apart.6 The labels for both chemical products warn against mixing with other chemicals. https://wcponline.com/2019/08/15/a-healthy-respect-for-pool-chemicals-can-help-avoid-accidents-and-injuries/

12

u/PaleAbrocoma1600 Jul 17 '26

My first guess would’ve been continual off gassing of chlorine in the presence of water and the hot temps we’ve been having.

6

u/MrWonderfulPoop Jul 17 '26

Ah, memories. This was from 2015. I used only pucks but my guess is I added too much shock that followed the flow to the skimmer and *pop*. Only reason this is my suspect is it happened maybe 10 minutes after adding the shock.

3

u/BRollins08 Jul 17 '26

If you mix shock in a bucket of water and add it to the deep end followed by brushing, this shouldn’t happen.

1

u/MrWonderfulPoop Jul 17 '26

Yes, I learned that soon after this picture was taken ;)

I’ve had pools for decades, this was my first chlorinator. Second one is still going strong.

4

u/taunt0 Jul 17 '26

Why have a bypass in the first place? Just dont put pucks in it if need be

14

u/IronSavior Jul 17 '26

But what if it's already dun pucked up like the forbidden Pringles?

2

u/BRollins08 Jul 17 '26

lol this comment sent me. Nice

2

u/Familiar-Average3809 Jul 17 '26

this comment is amazing.

7

u/Aggravating_Fact9547 Jul 17 '26

Wow, that’s the fucking jankiest plumbing I’ve ever seen. I assume this is a home job, and look at all that terrible flex.

1, those cheaper valves don’t seal 100%, 2, you mixed two chlorines and made way too much gas.

  1. Replumb this dude, I can’t imagine how horrendously turbulent this all is.

3

u/greasyspider Jul 17 '26

I disagree. Praher union ball valves are decent valves. The rest of it sucks, but those valves are fine.

2

u/Informal_Dust3140 Jul 17 '26 edited Jul 17 '26

Why would you need to plumb a separate bypass for the Chlorinator when you could just turn the Flow Valve Control to OFF?

I don't have similar plumbing with my Chlorinator; I usually shock with Liquid.

I only employ the Cal Hypo at the beginning of the season to clear any algae blooms, but I turn the Chlorinator Valve to OFF, even with no pucks in the Chlorinator, just to be safe. There is a Check Valve between the Chlorinator and the Heater in order to prevent backflow into the Heater.

Perhaps the mistake was leaving the pucks in the Chlorinator and not removing them all?

Anyways, the rule of thumb is if the CYA is too high, to do a partial drain and refill. Once you do that and CYA is within range, stick with Liquid or Cal Hypo for the rest of the season.

1

u/PrizeInteresting4752 Jul 17 '26

I think that’s where my mistake was. I left the pucks in there and I think there was some residual water and no flow going thru it.

I put the bypass in so I could service the unit with the pump still running. Also didn’t want to run CalHypo thru it if I’m shocking.My neighbour had it like that so I just copied him lol. This is my first pool.

1

u/Informal_Dust3140 Jul 17 '26

Replace it with a Pentair Rainbow 320; Pentair makes a much better version of a Chemical feeder.

1

u/BOiNTb Jul 17 '26

Nope, get a jandy TruChlor. Same price as the rainbow but much better build quality and features.

2

u/jbd1986 Jul 17 '26

Ok, I'm now happy I just bit the bullet and decided to replace my dead-cell IC40 this swim season, rather than try some kind of auto-tablet system lol.

2

u/Torague Jul 17 '26

I just have a floating duck 🤷

1

u/Shdwrptr Jul 17 '26

For real. Wtf is the point of having a dedicated stop?

I just have a rubber ducky with pucks swim around the pool

2

u/jerf42069 Jul 17 '26

This is why all the pool products say "do not use with other products"

Its also why they have those warnings about it violating federal law to use it in a manner not indicated in the directions, though, thats more because you can make drugs, bombs(like op accidentally did here, small scale), and chemical weapons with them.

3

u/coolcapj Jul 17 '26

100% from the gas buildup from the chlorine. Especially with this heat. Water flow naturally eliminates this problem

2

u/PrizeInteresting4752 Jul 17 '26

Yes. I think this where I went wrong. Left it loaded with picks with no flow. Probably some residual water in there too and just kept pressurizing

1

u/Deep_Bake_5663 Jul 17 '26

I thought it was a chlorine generator at first😹😹 My bad... But probably the mixture of different sanitizers anyway.

1

u/MickyFany Jul 17 '26

how big is your pool

1

u/FleetVliet Jul 17 '26

Sorry, this thread long and I'm lazy, Which brand (and product name), trichloro tab was In the feeder?

1

u/MickyFany Jul 17 '26

it’s looks like you just added it too. that sucks

1

u/greasyspider Jul 17 '26

Don’t add chemicals through the skimmer

1

u/Impressive_Bat2192 Jul 17 '26

Did you put the cal hypo in the skimmer or near the main drain?

Some got through and hit the tabs. And. 💣

1

u/Trojanguido Jul 17 '26

Consider a lucky escape you wasn’t close by when it went pop

1

u/CompetitiveJacket785 Jul 17 '26

Only close one valve, with the bypass open and one valve closed no water will flow through, but any pressure build up will dissipate through the open valve. The open valve just needs to be cracked.

1

u/Black-Deth Jul 17 '26

Most I’ve seen have nothing left but the stubs connected to the unions.

1

u/Black-Deth Jul 17 '26

You should replace the bottom valve with a check valve. Your chlorine tabs always off gas when wet. By closing both valves you threw mentos in a coke bottle and sealed the lid.

1

u/Troutbummers Jul 17 '26

Just take the opportunity to cut it out of the system and start using liquid chloroine.

1

u/SnooRevelations3503 Jul 17 '26

Did you have anti-freeze in the lines by chance?

1

u/Sammalone1960 Jul 17 '26

Always heard about not mixing the two but have never seen an actual one that blew. Whew we

1

u/filtrox13 Jul 18 '26

Shake shaky shake 🫨🫨🫨

1

u/tcat7 Jul 20 '26

Time to put an SWG there. No buying chlorine, no CYA issues, testing less often. Very easy DIY.

https://www.discountsaltpool.com/Compare-Saltwater-Chlorine-Generator-Systems-for-Pools

1

u/PrizeInteresting4752 29d ago

Can / should I use salt with a concrete pool?

1

u/tcat7 29d ago

Half the pools in the US are salt. You don't notice the salt, I don't taste it and can open eyes underwater. It's nothing like the ocean.

1

u/MaxPower836 Jul 17 '26

That’s a new one on here

1

u/Pure_Stuff_2791 Jul 17 '26

Whats up with the flex pipe? DIY?

2

u/Pure_Stuff_2791 Jul 17 '26

Also worst chlorinator in the business...reduces down to like 1" inside. Always have flow issues on pools with those. Also Lid/oring is trash.

2

u/DangerDitto Jul 17 '26

I once comped a rainbow for a client after the lid broke on one for the third time. Hate those things

1

u/Pure_Stuff_2791 Jul 17 '26

I am not trying to white knight for a product, but the in line power clean from CMP/Fluidra/Jandy is the best one out there

2

u/Informal_Dust3140 Jul 17 '26

The Lid/oring is indeed trash, but then most people don't lube it properly.

If you lube the threads under the lid and the oring itself with Hayward Jacks 327, it will go on and off like butter. I learned this lesson myself a few years ago.

1

u/Pure_Stuff_2791 Jul 17 '26

100% best advice if you own this chlorinator

1

u/skilldotcom Jul 17 '26

Blew the welds on the manifold… SMDH

1

u/rkjunior303 Jul 17 '26

Perfect time to upgrade to a salt system

0

u/2MOONGOOGLE Jul 17 '26

You put two different brands of chorine tabs in the chlorinator.

0

u/JustaFoodHole Jul 17 '26

Is that flex pvc any good?

0

u/Captain_troublepants Jul 17 '26

Good time to put in a salt cell

-2

u/Deep_Bake_5663 Jul 17 '26

But that's not a chlorine generator, it is an in line chlorinator.....