Safe to swim ??

tnewton7

Well-known member
May 5, 2008
59
Louisville,KY
#1
Just wondering what you guys think is a safe time frame to allow swimming after adding bleach to pool. I pour the bleach slowly over a return in the deep end. It has a strong output flow and the bleach appears to dissipate rapidly into the pool. I am wanting to add 2 gallons of 6%, but company is on the way and I dont want any issues with the bleach.
 

poolhound

LifeTime Supporter
May 17, 2008
54
Elgin, SC
#2
If this is just a maintenance dose (will not raise FC to shock levels) you can jump in as soon as your done pouring. I would spread my pour among all your returns to get quicker distribution.
 

mac4lyfe

LifeTime Supporter
Jun 8, 2007
212
Houston, Texas
#5
This brings up a question I have as well...

CYA ........... Min FC3 ..... Target FC ...... Yel/Mstrd Min ...... Shock FC ..... Yel/MstrdShock
70 ............... 5.1 ............... 8.0 .................. 10.5 ................... 27.52 ............... 40.52

According to the Chlorine to CYA chart, a CYA of 70 means the target FC should be 8 ppm but what would be the max FC safe to swim in? Can you swim in shock level 27.52ppm? how about the yel/mstrd min level?
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
#6
There isn't a clear sharp line of "this is safe and that isn't", people disagree on where to draw the line. Public indoor swimming pools sometimes have amazingly high active chlorine levels, nothing you would ever see with a CYA of 70. At those levels there can be damage to hair, bathing suits, and possibly accelerated corrosion of metals, but people do swim at those levels.

Personally, I feel that anything below shock level is alright. But other people set their line higher or lower than that.
 

tnewton7

Well-known member
May 5, 2008
59
Louisville,KY
#7
One more question along these lines. How long should I wait to test chemical levels after I put liquid bleach in the pool. I have a good flow rate in my pool. I am concerned that testing too soon will skew the numbers. As a side just ordered the TF-100 and am looking forward to getting this BBB down pat!!
 

mac4lyfe

LifeTime Supporter
Jun 8, 2007
212
Houston, Texas
#8
I would think that depends on many different factors like what is your pump capacity and how long does it take to completely recirc the entire pool. Most pool pumps are sized to recirc a pool in 8-12 hours but some may take 24 hours. I would take this into consideration as well as where are you sampling and where are your return lines. Ideally waiting for the pool to completely recirc would be best but in cases like FC it may be already vastly different several hours later. I usually add chlorine during the evening and wait at least a couple of hours to test (which is pretty sufficient recirc time). I also have a robot and sometimes run it as well which takes about 2.5 hours. After that my pool is pretty much mixed.

I usually test for PH and FC at night and in the morning. I've had previous problems with algae so I like to check if FC is being consumed at night. Whatever you do, consistency is key. You may want to add chemicals at night and test in the morning or vice versa. You also want to test in the same area of the pool or several multiple areas of the pool. Just stay consistent so you will notice trends.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,082
San Rafael, CA USA
#9
Most pool chemicals once dissolved in water mix rather quickly. The main exceptions are thick chemicals such as PolyQuat algaecide or some clarifiers. It does not take one turnover to mix the pool water thoroughly -- circulation through the filter vs. mixing of the water are different though related things.

I've done tests in my 16,000 gallon pool using a pool dye (GLB Party Blue) and also testing FC levels at one end of the pool after adding chlorine at the deep end over a return flow (at around 48 GPM distributed through 3 returns, so around 16 GPM each). Most of the chemical was dispersed and measured at the other end after only 10 minutes, though continued increases were seen to around 20 minutes and after 30 minutes I would say it was effectively thoroughly mixed. So in a pool with decent circulation and the pump running, it doesn't take long.

Richard