I went to remove my winter cover yesterday. Water is a bit cloudy, I tried to shock the pool, but the FC is rising very slowly. The water temperature is 50, after adding about 5 gallons of chlorine(sodium hypochlorite 10.8 %), the FC is only about 0.5, the pool is about 8500 gallons, I have not started the pump or heater. Should I keep adding more chlorine or should I wait till I bring up the water temperature and shock again?
Chlorine level in cold water?
- Thread starter Ke
- Start date
you need to circulate your water quickly...your low fc is most likely that the liquid chlorine has not mixed well with the water
5 gallons of 10% at once in a 8500gal pool is enough to raise your FC to 60+ppm
Yes, what dmanb2b said. You need to have some circulation going or the chlorine can all "pool" on the bottom and possibly damage the pool surface. If turning on the pump is difficult, brushing the pool will mix things enough to solve the imediate problem.
Thanks for the quick reply. I just placed my cover pump into the shallow end and dropped the hose at the deep end to help to circulate. I'll post back in about half an hour. Funny thing is, despite having added so much chlorine, I don't get a very strong chlorine smell around the pool.
I just tested the water, FC is still at 0.5, I even raised the temperature of the sample to 75 F (by placing it in a microwave), FC is still at 0.5. Is it possible that I got a bad batch of liquid chlorine? Because even right from the bottle I could smell chlorine but not very strong, my wife confirmed that. The chlorine comes in a 5 Litre plastic bottle, it has a screw cap, you press down to open, but there isn't a paper or tin foil seal on the opening, is it possible that these are last year's left over stock and over time, some of the chlorine has dissipated? I have no other explanation.
I'd bet on it.Ke said:
There's a big box hardware store near me that sells pool stuff out in the garden area. (Can you guess who?) The pallet of Chlorine looks pretty weather-worn, so I've given it a pass.
Sorry everyone, I just tested the water again, the FC at the deep end is over 60 and only ahout 5 at the shallow end, so it has to do with circulation, my CYA is less than 20, now should I worry about too high chlorine, tomorrow will be a sunny day, I should just let daylight break down the chlorine. At least my pool gets a good shock.
60? Yikes - yes, definitely let the sun do it's work. 
Did you use the pool calculator first, do determine dosage? high FC levels can be corrosive, best not to make mistakes like that in the future.
Did you use the pool calculator first, do determine dosage? high FC levels can be corrosive, best not to make mistakes like that in the future.
Tonight the FC is down to about 20. I have the cover pump running non-stop. I will wait till the FC to fall below 10 before turning on the pool pump.