What concentration of bleach in reservoir?

[rollymon]

I am feeding my pool with a Pulsafeeder Mec-O-Matic VSP 20 Variable Speed Peristaltic Metering Pump (Chlorinator) using 6% ultra bleach. The unit is almost new and seems to be operating fine. I have monitored usage by marking levels in reservoir and setting pump speed and timer to same settings for a couple of weeks. Usage is consistent. My FC is flucuating more than I think it should. The only variable that I have not controlled closely is the mixture in the reservoir tank. I think this is the weak link. Is there a reccomended dilution rate or minimum strength that should be maintained for this solution in the reservoir? I run the chlorinator pump from 2 am - 6am everyday and when I test water in the morning at 9am everyday the FC is 3 - 4 ppm however by days end it is often .5 - 1.5 My numbers are listed below. Please advise.

FC 3 - ppm
CC 0
TA 120
PH 7.6
CH 130
CYA 40
TDS 350

Thanks,

Rollymon

 

[JohnT]

Losing that amount of chlorine on a sunny day isn't all that surprising. Sunlight is your biggest consumer of chlorine.

 

[JasonLion]

If the tank is cool and dark then you can use almost any strength of bleach in it. If it gets direct sun and gets quite hot then you might want to use diluted bleach to reduce the rate at which the bleach degrades or better yet shade the tank.

Sunlight breaks down chlorine, more slowly when you have CYA, but even with lots of CYA the chlorine will still break down in sunlight. If you are only pumping at night you need to get your chlorine level up high enough by morning that even after the sunlight reduces the chlorine level there is still enough chlorine to be safe.

Depending on how much sunlight your pool gets, at a CYA of 40 I would expect you to lose between half to perhaps three quarters of your chlorine acorss a sunny day. If people are swimming in the pool you will lose even more.

 

[rollymon]

Jason

Thanks for the reply. My tank is in tucked in a corner of my equipment room within 2-3 feet of the pump and the injection port on the return line to the pool and is never in direct sunlight. My tank is solid plastic and is dark brown in color with a vented lid that is always kept on it other than when replenishing solution. Do you think then that I would be most effective using the 6% bleach concentration right out of the manufacturers bottle and then throttling my pump interval timer and rate to get my desired resultant levels of FC? Any reason I should be running the chemical pump twice a day? Would two dosing intervals help to maintain more consistent levels?

I realize also that the SUN is my biggest culprit in my loss of FC and am presently deciding where to purchase my solar cover. My pool is in totally unobstructed sunlight all day long. At least as much totally unobstructed sunlight as we get in North East Ohio! 8)

Thanks Again,

Rollymon

 

[JasonLion]

With the tank inside using 6% bleach should be fine.

For the most consistent FC levels you need to be feeding bleach at the same time that chlorine is getting consummed, which means feeding bleach the entire time the sun is shinning on the pool.

 

[hamop78]

Your set-up sound like mine. I mix 1 jug Clorox Ultra with 1 jug pool water. I test the solution and normally it is around 3.55%. My tank (15 gallon, light brown & opaque) is outside and in the sun. I have tested when my tank is nearly empty (about a week after filling) and show almost no loss of chlorine percentage.