Flocculates can be added any time you like. And generally should not be put through the filter of the pool.When you add a floculant it is best to stop the pool altogether for a couple of days to allow the flocculate to settle along with the impurity's to the bottom of the pool. you will note a cloudy layer at the bottom of the pool when this has happened.Hand vacuum this layer carefully to waste. Do not put it through the filter. you may have to repeat the procedure until the water is entirely clear.
Chlorine
Add sodium bicarb to raise pH. Chlorine will go down by itself or add sodium thiosulfate
Hydrogen Choloride
Use one gallon of chlorine for every 10,000 gallons of water.
Do you mean that adding a little chlorine made the reading go from 0 to a higher level? You should shock your pool once a week with 1L of liquid chlorine per 10000L of water in your pool. You need to add enough chlorine to break apart the combine chlorine (the combination of chlorine and dirt which doesn't sanitize.) If you don't add enough at once, it will be used up and the chlorine reading will remain low.
It is best to add chlorine in the evening, during the day there is a good chance the sun will burn it out before it gets a chance to work.
Because sunlight breaks down the chlorine. If you add it in the morning and the sun breaks it down, you may end up with little or no chlorine in your pool by late afternoon. If that happens you will have very little defense against algae all evening and night, until the next morning. If you add your chlorine in the evening then your pool is protected all evening and night, and the sun doesn't start working on it until morning. If the chlorine is low or gone by late afternoon and you dose the pool again in the evening, there is very little time when your pool is unprotected!
Testing kits are available to indicate when this is required. the best time of day to do this is in the evening as the nigh with no sunlight will not loose you as much chlorine until the next day.
Yes, you can add chlorine granules and algecide.
Add a clarifier, available at you pool supply store
Chlorine
Add more chlorine.
Assuming the liquid is water - add a flocculant (eg; Alum) and allow the sediment to settle.
You have to add more chlorine.
You can add liquid chlorine by walking it around the outside edges of the pool or adding 3 inch tablets through a chlorine floater.
Add chlorine
Add sodium bicarb to raise pH. Chlorine will go down by itself or add sodium thiosulfate