Pentair 320 inline chlorinator

sewilson

New member
Aug 21, 2018
2
Chicago, IL
I have a 21k gallon vinyl liner in-ground pool. I’m having an issue with my inline chlorinator, a Pentair 320. I started the season by taking the whole thing apart and cleaning it. The control valve seemed to function fine (when set at 0, nothing passed through) and all of the tubing was clean and clear. When I put full 3” chlorine tablets in and turned the control valve to 5, the tablets wouldn’t break down and the chlorine levels in the pool were almost non-existent. (Testing with a Taylor kit, I would usually get a reading of 0 ppm.) This went on for more than a week. So I decided to break the 3” tablets apart. I put those in and my chlorine levels skyrocketed (even at a low setting of 1 on the control valve.) Testing with a Taylor kit showed chlorine levels around 7.5 ppm.

So, in order to reduce the chlorine levels, I turned the control valve to 0. However, even set at 0, I’ve found that tablets are still breaking down and entering the return stream. Shouldn’t setting the valve to 0 stop all flow out of the chlorinator?

I should mention I’m using the lower port on the chlorinator to connect to the control valve; the top port is sealed closed.
 
Last edited:

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,536
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
Welcome to TFP :)

Your dealing with the devils candy right there... the fast food for pools.. 3 inch pucks work great for a little while then the CYA gets above 40 and your pool starts turning green.. then the pool store has you "shock" it with Dichlor once a week and that adds CYA and then you add more 3 inch tabs and the next thing you know your pool is completely green and will not turn blue anymore even with shock...

Now your pool CYA is way over 100 and you have to empty half or more of the pool water just to start over and go down the same path... the pool store is not your friend, yes the "test" is free but all the potions they sell are not and when they stop working you empty the pool and start over costing thousands of dollars...

rinse and repeat 2 to 3 times a year...


Now the great thing is you found us.. :)

There are 3 ways to do chlorine for your pool

1. the way I explained above..

2. daily adding liquid chlorine the TFP way, it will give you water so clear you will not believe there is water in the pool..

3. Salt water generator.. it makes the chlorine for you out of salt in the water..

all 3 types of chlorine cost the same in the end and all 3 work... 1 will cost more because they need to make money of you to stay in business...

Nice job on the Taylor test kit.. you are already there.. now you need to make a decision on how you want to chlorinate the pool :)

ABCs of Pool Water Chemistry

FC/CYA Chart

Recommended Levels
 
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sewilson

New member
Aug 21, 2018
2
Chicago, IL
I appreciate your reply. I haven’t dealt with a pool store in a few years. And I hope that in the future, I’m able to care for my pool the way that’s discussed here. Fortunately, my pool isn’t green and hasn’t been green for years. In fact, my pool water is crystal clear.

In the meantime, though - I would like to find out what the issue is with my existing chlorinator. Pentair is a huge company - they have to make inline chlorinator for a reason, and reasonably they should work. Does anyone else have any suggestions?
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,536
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
ahhh, sorry.. most come here when there pool turns green and wondering what is going on.. :)

I have never had a chlorinator and never will, wish I could help...
 
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