frogabog said:I'll also add that clarity for shocking is not exactly subjective. "Clear" is rather a state of, "not unclear in any way". It's not clear till it's not unclear. Meaning, there's no doubt that nothing is clouding the water. "Crystal freakin sparkling perfectly crystal, you can tell the time on a wristwatch in the deep end clear" and "clear" are also not exactly the same thing (close, but no).
Here's why clear is important:
When algae dies it turns white/grey. Little corpses floating about in the water. They are like zombies and can return to life. The filter has to get a chance to capture them before they do so. This clouds up the water, and not always a whole lot. If you have a light, look at night, they'll be passing past it. Reducing chlorine levels gives them the opportunity to revive. This would be why the third criteria, clear water is often overlooked or subjectified. When you start to see through the water after having it go cloudy or green it can seem all kinds of clear, but it's still not unclear. Like reasonable doubt... err on the side of caution if there's any question about clarity and continue shocking.
I found this to be very entertaining ... and clearly not unclear in the least