Safely adding bleach


LifeTime Supporter
May 15, 2010
Kelseyville, Ca
chem geek said:
Any source of chlorine improperly applied can result in liner degradation. For any concentrated source of chlorine, it needs to be thoroughly mixed with the bulk pool water. For Cal-Hypo, this usually requires pre-mixing in a bucket of water to get it to fully dissolve before adding it to the pool. Even when adding other powdered chlorine (Dichlor, Trichlor) or adding bleach or chlorinating liquid, it is important to pour slowly over a return flow with the pump running and then for extra safety to lightly brush the side and bottom of the pool to ensure thorough mixing. Even with bleach and chlorinating liquid, you could have them fall to the bottom of the pool as they are denser than water until thoroughly mixed.

Of course, there's nothing worse than a Trichlor puck (or granulated Trichlor) against a pool surface (for too long) as it is not only concentrated chlorine, but very acidic as well.
This quote addresses one of my concerns. I have seen posts describing how to add bleach. When I was using 6% from walmart, I slowly poured it into the skimmer flow. Now that I am using 12%, I would like to know if it is mixing correctly and how long after adding the chlorine is it safe to swim. I only have a skimmer and one return flow. The eyeball flow is pointed down and I can see underwater movement on probably half of the pool.


TFP Expert
LifeTime Supporter
Feb 23, 2008
Denton, TX
I would just pour it in front of the return jet. That is how I have added both 6% an 10%. Of course, I have dumped bleach into the skimmer too. Just pour slowly. That's the key.

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
SouthWest Alabama
As 257 said, pour it in front of a running return. I swim 30 minutes after pouring it in (I've actually swam sooner than that, but I don't recommend you do it).


Mod Squad
TFP Expert
LifeTime Supporter
Apr 17, 2010
East Texas
I angle my return eyeball up to where it puts a good ripple on the surface and pour slowly-2 minutes per gallon.


Jun 19, 2010
Bama Rambler said:
As 257 said, pour it in front of a running return. I swim 30 minutes after pouring it in (I've actually swam sooner than that, but I don't recommend you do it).
I actually pour in the bleach while in the pool. Just be careful not to pour on yourself. I walk around the pool slowly pouring and mixing with my other hand. This may be crazy but it has worked so far.


Bronze Supporter
LifeTime Supporter
Oct 6, 2009
I've been pouring my Bleach directly in front of the returns and I always notice the formation of a milky white cloud in the water, which lasts for a few minutes until the water circulates a bit more. I recently tried pouring the bleach into the skimmer, expecting to see the return shooting out a cloud of white water, but it did not. Could it be that the skimmer method is actually helping to mix in the bleach better than simply pouring it in front of the return? It sure is a lot easier for me to pour it into my return, but wasn't sure of any negative or positive effect by doing this. Is it OK to pour in the skimmer? When I was using the pucks, they were going into the skimmer (although I learned from this forum the downside of that - as when the filter is off, the pucks continue to dissolve creating a concentrated amount of chlorine in the skimmer).



TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
When you pour in the skimmer, any cloudiness is getting filtered out by the filter before the water comes back into the pool.

The cloudiness is almost certainly calcium clouding and that suggests that some combination of your PH, TA, and CH levels are too high.


Bronze Supporter
LifeTime Supporter
Oct 6, 2009
Wow, thanks Jason. I really still have so much to learn about pool chemistry!! Didn't realize the cloudiness I see is the result of calcium in the water. Here are my current levels. I actually thought my CH level was too low and was about to go buy some calcium chloride to increase it.

FC - 3 (just added 182 oz jug to reach a target of 7, after this reading)
CC - .5 (usually it's 0 - but it just rained)
pH - 7.5
TA - 90
CH - 180

P.S. This is a brand new plaster pool (less than 2 months old). Could this have something to do with it? I'm not seeing any rise in pH.


TFP Expert
In The Industry
Jun 12, 2009
Exeter, PA
cal-hypo always clouds to some degree when adding it to the water, but the cloud doesn't last too long unless there are water chemistry issues.


Bronze Supporter
Jan 24, 2010
Just be careful with spash-up...I was pooring bleach into my measuring jug back last month..It was hot,had a little bit spash onto my nose&lip...I didn't think nothing of it,Took my wet hand and thought I had wiped it off..A month later my lip would never get better...Ended up at the skin doctor..She had to do a little work on it ..It is getting better,still not a 100%....After all that I wouldn't change a thing with the bleach...In 11 yrs I believe this has been the best summer of all with the pool....Have had no problem's&water is clear all the time& my number's don't bounce around...


Active member
Jul 29, 2010
I have poured it in the stream that come out of the spa, which I am sure is 50-60 gpm and I don't pour too slowly just slow enough not to have splash up. I know it is more dense that water but why would you need to pour so slowly?


LifeTime Supporter
Aug 20, 2009
North Central Texas
I guess I'm overly cautious. I walk around the pool and pour pretty evenly into the streams of each of four returns (one return has a small fountain, one has a Pool Skim, and two others are eyeballs) bending down and "floating" the bottle. I usually leave a little to put at the end of pool, with an eyeball close on one side and skimmer close on opposite side, and bottom drain not too far away, just so I can see how fast the cloud disappears. I usually add at night with light on. I can usually tell almost exactly what my pH is by how fast the cloud disappears, from 7.0 to 7.5. (I like to keep it at or a little below 7.2 because I'm working on dissolving calcium scale and lightening copper stain, and keeping iron stain at bay, using a sequestrant and low pH.) At pH of 7.0 the cloud is gone within seconds; at 7.5 probably a minute.

If I miss my every other night addition and have to add more than usual I'll go around the pool twice doing above procedure.

Working on the calcium scale and copper stains I am very wary of letting high chlorine level get too close to any of the surfaces.



Well-known member
Feb 2, 2008
Northwest Indiana
Once a week I pour directly into the skimmer with my valve for my Solar Bear heater open because it goes through the filter and right into the panels before going into the pool...I don't know if that makes a difference but I could imagine especially if I have had the heater turned off for a couple of days that water inside the heater could get pretty foul. So especially then I run the bleach more direcly into the panels. Must of the time I pour directly into the torent of current my 2 hp hayward makes...

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