Hi. I've read the closing an inground pool process. It says to SLAM a few days before, and let it come down to normal as long as the Overnight test holds.
1. However, if I consistently do not have any CC showing, do I need to SLAM at all before closing?
SLAMMing before closing the pool for the winter is not mandatory. It gives added comfort to some folks.
I raise FC to about half SLAM level before closing.
2. I do add polyquat 60 before draining and chlorine after draining the water. If adding polyquat 60, shouldn't I add it after draining so as not to lose some in the drain? Maybe stir up the water after draining to mix it in?
www.troublefreepool.com
The following is Buckman Labs’ recommendation on how to use Polyquat 60 for closing your pool for the season.
As they recommend for proper winterization, the pool should be "shocked" with about 5-10ppm chlorine to destroy any lingering oxidant demand and remove any residual ammonia or chloramine, etc. After a couple of days, adjust the pH back to 7.2-7.6 and then add Polyquat 60 at the maximum rate as instructed per the label. This approach allows you to receive the highest benefit from both chemicals.
Note that Polyquat and linear quat algaecides are organic compounds that are known to cause interference's with certain color indicating reagents like pH indicators. Adjust the pH before adding Polyquat 60 and there is no reason to test pH after adding it.
Another point that they make regarding using this algaecide in pool water is that after the addition of Polyquat 60, it’s important to keep the circulation pump on for at least 24 hours to make sure that the algaecide is thoroughly distributed throughout the pool.
If you raise your water to SLAM FC level then you should let the FC drift down before adding Polyquat 60. Having a moderately higher level (½ SLAM level so the FC/CYA ratio of 20%) is okay as well. The idea is that the Polyquat should last through the winter even if the chlorine does not.
Buckman Labs says that even if the Polyquat is broken down, it is still effective when used as an algaecide. Moderate to high levels of chlorine break down Polyquat but it still only transforms the formula into shorter chain polymers that are still just as effective.
