Need advice on how high to raise chlorine to shock

[gdog2004]

Hey guys. My pool was light green with all kinds of dirt in it after a crappy pool cover fell apart over the winter.
I was unable to read the CYA level because I ran out of the chemical used to test that.
So--is it safe to assume that over the winter it would be down to zero ?

So Prior to doing anything my measurements were:
CYA : 0 (based on assumption)
FC : 0
PH: 7.1



I added two packs of dicholor (which would bring CYA up to 12)
I then added enough chlorine to bring it up to 15.
I also added enough Borax to bring the PH to 7.4
I vacuumed thoroughly twice and scrubbed down the sides of the pool liner.

After a day of no sun, the chlorine went down to 12.
The pool after all of this looks MUCH better but still cloudy. So here's my questions

Am I correct in assuming CYA would have started off as zero since I opened the pool?
If I bring the fc up to 16 to continue killing the algae would that be too high ?
I will get my CYA chemical tomorrow so I can test it more accurately.

thanks in advance guys.

 

[Richard320]

No. Some people have found their pools sparkling, the CYA unchanged, and residual FC still in the water when they opened. You can't assume it went to zero.

There's no way to know how high to take FC without knowing the CYA value. With zero CYA, SLAM level is 10. You can safely keep it there, but it may not advance the cleaning any.

 

[gdog2004]

No. Some people have found their pools sparkling, the CYA unchanged, and residual FC still in the water when they opened. You can't assume it went to zero.

There's no way to know how high to take FC without knowing the CYA value. With zero CYA, SLAM level is 10. You can safely keep it there, but it may not advance the cleaning any.

Thanks. I should have measured CYA but after I took the pool cover off I THEN realized I didn't have any more of the chemical needed to measure. I didnt want the pool to sit in sun with algae so I just went to work.
BTW --can I get an accurate measurement of CYA while the FC is up around 15 ?

 

[Richard320]

Thanks. I should have measured CYA but after I took the pool cover off I THEN realized I didn't have any more of the chemical needed to measure. I didnt want the pool to sit in sun with algae so I just went to work.
BTW --can I get an accurate measurement of CYA while the FC is up around 15 ?

Yes. Only pH gets skewed by the high FC. TA may go from green>pink to blue>yellow but the results are still good.