We need to for sure get an accurate CYA level on your pool. Pool store said 25? You say 5? Markings on the bottle are 20 and 30.... CYA will determine what our shock level is for SLAM based on this chart: Chlorine / CYA Chart - Trouble Free Pool
If you have been using tablets in a floater all this time then it can't be zero... Does it cloud up at all? When you fill all the way to the 20 mark it's still clear and you can still see the dot?
If CYA test stays clear (no clouding), then let's add 30ppm stablizer in a sock in the skimmer. Use Pool Math to determine amount based on pool gallons. Lower pH to 7.2. Then go into full SLAM mode and hold chlorine level at 12 while running the filter 24/7 until it clears.
I get mine at Wal-Mart, Lowes or Home Depot. It will say "Stabilizer" or Cyanuric Acid. It's needed so your chlorine doesn't get used up immediately by the sun.
The SLAM process is basically bringing your FC level to an elevated level (based on the FC/CYA chart) and keeping it there until all the algae is killed in the pool. I recommend reading the article several times until it clicks. SLAM - Shock Level and Maintain - Trouble Free Pool
OK, go to your local wally world and find the clorox pool stablizer. Then download the Pool Math application or go to this page PoolMath and put in all your info and set your current CYA at 0 and your goal of 30. It will tell you how much (by weight) of the stablizer to put in. It comes in a 4 lb jug. Add the amount you need to an old sock and place the sock in a skimmer or hang it in front of a return to let it dissolve out of the sock. It's VERY slow to dissolve (hours). Then, yes, SLAMing means raising your free chlorine level to at least 12 and holding it there. Use your test kit to check your free chlorine level as often as you can (at least twice a day but 3 4 5 times even better)... and then add chlorine often to get it back up to 12. Your goal is to hold it at 12 until the pool clears. Once the pool is crystal clear, we move on to next steps. While SLAMing, run pump 24/7 and get as much debris out of the pool as you can. Keep an eye on pump pressure and backwash/clean as necessary. No tablets or powdered chlorine during this process. Liquid only.
Ignore the current goals. You are SLAMing. We find our goal in this chart: Chlorine / CYA Chart - Trouble Free Pool -- Since we are assuming your CYA is 0 or maybe 5 or 10.... and we are going to add 30 ppm CYA, our new CYA will be somewhere between 30 and 40. So your SLAM target is at least 12 and maybe even as high as 16. Those are the levels that we can max out your chlorine at for a temporary period and hold there to kill all the algae and bacteria and help to break it down so your filter can clean it out and make your water pretty again.
Make sure you enter your pool volume so it knows what to base calculations off of. From there, set your current CYA at 0 and your goal CYA at 30. It will use the gallonage of your pool to calculate how many ounces or pounds of CYA we need to add via the sock method to your pool.
Your current chlorine of 13 is fine, but it will drop overtime from sunlight (especially with no CYA in the water) and from killing algae and bacteria and waste in the pool. We are at war with algae and to kill the algae dead and gone we are gonna hold at 12 or slightly above but no more than 16 and run the pump 24/7 until it's all cleared up. This will require you to test the chlorine level several times per day. Set your current chlorine at whatever you test and set your goal at 16 and it will tell you how much to add to make up the difference. This is done the same way as you calculate how much CYA to add. Just put in your current value and then what you want to be at and it will tell you what to add to get there. Same with pH.
My pool is 11, 000 gallons. I set the settings soon as I installed the app, it is correct. Ok it says add 6% chlorine - 2 quarts. I still have 3 bags of shock left. Can I use them and then the liquid chlorine?
There are different options other than just 6% chlorine in the app. There is 8% I think, 10, 12.5%. You just choose what it is that you have on hand. Different areas of the world/country have different concentrations available to them, so there is options for different strengths. Since your calcium hardness based on testing was 150... you most certainly CAN use calcium hypochlorite (your shock ReFresh bag you posted). That 1 bag will add 7ppm free chlorine and 5ppm calcium hardess. You are currently at 150 but don't go over 350 so you can only use that type of chlorine 40 times and then stop because each time it will add 5ppm calcium hardness.
Remember ...when you read the recommended chlorine is 1-3ppm that is for when you have no stabilizer in the water but also NO ALGAE!
If you have algae (cloudy water for example) you need more FC than normal so that you can kill this living algae.
Ok I'll add 1 bag now, pump on. Then fill pool later so I can vacuum to waste. This morning the skimmer basket had a few dead bugs and some round green things from the trees. Pump is running at 12 psi and ran overnight.
1. Get CYA dissolving in a sock/stocking. (I get a little over 2 lbs in pool math, so half a 4 lb container)
2. Once it's dissolved, keep FC at 12 (test and adjust often) until the pool is clear. Use liquid chlorine (bleach, chlorinating liquid from Wal-Mart, etc. Don't use Clorox)
3. Brush at least once a day