Can you over Chlorinate?

[nyjobz]

I started the BBB this year and my pool has been perfect...until now. A week ago I noticed my PH level was down to 6.8 so I dumped 1.5 boxes of Borax (6 lbs)in the skimmer. The FC level was 2. Two days later I went out to the pool and it's turning green. I immediately added about 10 gallons of Bleach. This helped but the pool was still cloudy a day later. Yesterday I added 6 more gallons of bleach, still cloudy this morning. I tested, the PH was down to 7.0 so I just added a half box 2 lbs) of Borax. Here are my numbers

FC 30
PH 7.0
CYA 60
Alk 110

What am I doing wrong? Thanks for any help.

[aylad]

With a CYA of 60, you should never let your Cl get below 5 ppm, or you will get an algae bloom, as you have already seen. To clear it up, you need to add bleach to get your pool to shock level, which is 20 ppm with a CYA that high, and hold it there by re-testing and adding enough bleach to get back up to 20 at least a couple of times a day. In addition, you need to brush daily and run your filter 24/7, since the bleach will kill the algae, but the filter is what removes it from the water. You don't mention how many gallons your pool holds, so I have no idea how high your Cl is with 10 gallons of bleach, but to clear your pool you need to sustain 20 ppm Cl until the pool goes back to blue/cloudy, then give your filter some time to get the dead algae out.

Janet

[poolrx]

nyjobz,

With your cya levels you needed to have you FC levels b/t 5-10 ppm. You did the right thing by adding the borax to increase your ph, but I think it would have been best to do it in moderation, a couple pounds at a time.
Yes, you can add too much chlorine. You will bleach you liner(if you have a liner) if the levels get too high.
With your CYA level of 60 you need to keep your fc levels between 15-20ppm throughout the day and night until the algae is gone. Brushing the sides and vacuuming the bottom will help the process. Continue to add the borax as needed, a couple pounds at a time. Be careful though as the bleach may increase your ph as well.
See Ben's Best Guess Table for more info and download the bleach calculator(if you haven't already) as well. Plug in how many gallons your pool is and it will tell you how much bleach to add to get to a specific level.

Also read read read-knowledge is power:) There is a lot of excellent information available on this site to help you.

[nyjobz]

Thanks guys. My pool is about 25K gallons. The chlorine level is still at 30 ppm and the water has gone from cloudy green to a dull blue (I can see the bottom of the 4 ft but not the 7 ft). I will backwash now and monitor.

[Watermom]

What kind of filter do you have?

[nyjobz]

I have a Hayward Sand Filter (240 series) with a 1 hp pump

[Watermom]

Many of us on the forum with sand filters routinely (after backwashing) add a little DE to our filters. It seems to help the filter catch more stuff. You only add enough to make the pressure on your filter rise by 1 psi. Premix it with a little water before pouring it in the skimmer. It will usually take 20-30 minutes for the pressure to rise, so wait a bit after the initial dose before deciding if you need to add a little more. It might help clear your pool faster.

[Simmons99]

Thanks guys. My pool is about 25K gallons. The chlorine level is still at 30 ppm and the water has gone from cloudy green to a dull blue (I can see the bottom of the 4 ft but not the 7 ft). I will backwash now and monitor.


Looks like you have killed the algae - so it will need to filter out. Keep your chlorine high until the pool clears - it will clear-up quicker that way. You can try turning off the pump to let it settle - then vacuum to waste (if losing all that water isn't a problem).