High chlorine demand, slammed the pool 2 weeks back

[missourian]

I slammed my pool 2 weeks back, chlorine levels were stable for a week, we had small rainfall 3 days back, now again I have high chlorine demand, spending too much money in chemicals . Only thing I suspect is black spots around the pool light fixtures, I don't know how to unscrew and clean those, never done that before. I backwashed my pool 2 weeks back during the slamming process, today I noticed there is a 7 psi increase.

My Current chemistry

FC 1.0
CC 0.5
ALK 70
PH 7.8
CYA 50

Any recommendations?

 

[jblizzle]

Rain does not cause "chlorine demand". You let the FC get too low and that lets things start to grow. Time to SLAM again.

Light should only require removing one screw on the top of the fixture.

You should backwash the filter when the pressure rises 20-25% over the clean pressure, likely 7 psi is way too much.

 

[missourian]

Rain does not cause "chlorine demand". You let the FC get too low and that lets things start to grow. Time to SLAM again.

Light should only require removing one screw on the top of the fixture.

You should backwash the filter when the pressure rises 20-25% over the clean pressure, likely 7 psi is way too much.

Thanks, Do I need to increase the Alkalinity to 90 before slamming? This time i want to slam it in a right way to avoid repeat.

 

[ping]

You do not need to adjust the TA, but you will need to adjust the pH to the low 7's before SLAMming.

Which test kit do you have? Without a proper test kit you will not know if you have completed the SLAM and will need to continually repeat it.

Follow the SLAM process that is linked in my signature.

 

[missourian]

You do not need to adjust the TA, but you will need to adjust the pH to the low 7's before SLAMming.

Which test kit do you have? Without a proper test kit you will not know if you have completed the SLAM and will need to continually repeat it.

Follow the SLAM process that is linked in my signature.

Ok, I have been using TF 100 since joining TF

 

[linen]

Thanks, Do I need to increase the Alkalinity to 90 before slamming? This time i want to slam it in a right way to avoid repeat.

Since you asked about raising TA I thought I would make sure you are using bleach/liquid chlorine to SLAM? We don't recommend trichlor or dichlor to SLAM since both of those add cya and lower ph (trichlor lowers ph more than dichlor).

 

[missourian]

Thanks everyone, just cleaned light fixtures, Oh my God, Nasty stuff . I just backwashed and loaded DE, according my filter specifications they recommended to charge 7.5 lbs of DE, I used attached cup, I measured 4 cup as 2 lbs. Is it correct to use?

 

[missourian]

Thanks, Do I need to increase the Alkalinity to 90 before slamming? This time i want to slam it in a right way to avoid repeat.

Since you asked about raising TA I thought I would make sure you are using bleach/liquid chlorine to SLAM? We don't recommend trichlor or dichlor to SLAM since both of those add cya and lower ph (trichlor lowers ph more than dichlor).

Yes I am using BBB method, no trichlor or dichlor.

 

[ping]

The only time to do a full charge of DE is when the filter is broken down and cleaned. You will only want to add around 75% of a full charge of DE. The most accurate way to know how much DE was added from your measuring cup is to weigh it if you have a scale that can measure it.

 

[missourian]

Its 3rd day of my slamming process, my CC is 0.5, water is crystal clear, I loose about 1.5 ppm of FC every 4 hours, as soon as I reach 1 ppm loss for every 4 hours is it safe to call off the slamming process?

 

[danacc]

You'll need a drop in FC of 1 or less overnight (OCLT) along with a morning CC of 0.5 or less before the sun hits the crystal clear water. For the overnight test, see: pool-school/overnight_fc_test.

Don't stop until then.