I have shocked my outdoor pool and it took 4 days to get it from algae green to crystal clear.
the methods were recommended by TFP ( meeting the 3 criterias etc..)
What i know...
1) using the pool calculator.
2) CL, pH, TA, CH, MA, CYA Langelier index.
3) Stabilized Chlor: Triclor 95%, Diclor 65%,
4) Non-stabilized chlor: Cal Hypo 65%, Sodium Hypo 13%.
5) Shocking the pool when:
-water becomes cloudy, DPD test kits shows up pink in the test kit, a loss of CL overnight.
What i am not sure of:
I have an outdoor pool at the 22 latitude (tropics). 7500 gallons w/sand filter.
When i shock the pool, (using the 'meet the 3 criteria' ), the water becomes really crystal clear and remains that way for weeks at 2 ppm or 3 (depending how much CYA is in the water).
the question is, i notice alot of dust and fine particles blowing into the water, obviously the sand filter cant catch
the finer stuff but eventually it ends up in the filter.
The real question is this :
at 2 ppm or 3, can the Chlorine really disolve or vaporize the stuff that does get stuck in the filter or wherever it is suspended in the water or on the floor ( i do sweep to keep the algea from getting comfortable or settling in)
is it normal to shock every 2 weeks if the water suddenly starts to slowly become cloudier?
( i do monitor the CYA, CL , pH etc , etc very often so that it doesnt wobble out of control )