An Introduction to My Pool - Old Plaster - Old Pool - Black Algae !

  • Cya <30 added 2.5 lbs to the sock so it should be approaching 25. Im gonna run tabs to get it the rest of the way if there is no issue with that.
  • CL - .5 ---> 3 with liquid this AM
    • I dropped 2 tabs in the floater this morning so it stops going to 0 in between rounds
      • Is this Kosher?
Use liquid chlorine. Pucks contain CYA and chlorine...no way to control the addition of each, bit of a get what you get. Using liquid chlorine and CYA, you control what is added.
CH - 300 headed to 350
  • will mix another 10 lbs or so to get there today
Why? 200 is what is recommended on the npc. 250 is just fine. Don't add more.

What is your CSI? In pool math, upper right gear, enable track CSI and track Temperature, and at the bottom enable sharing with TFP. Use your TFP login/password. That way we can see your logs.

Also i noticed this black spot appear about a foot below the tile in one spot
No idea. @ajw22 @JamesW @onBalance
 
  • Also i noticed this black spot appear about a foot below the tile in one spot. It feels like aggragate, i tried to brush it out as I was worried about black algae since my CL kept going to 0 periodically using the Liquid CL.
    • Is this just an errant piece of non quartz aggregate?
    • Brushing sort of created a little grayish swirl around the spot?
      • Should I be worried here?
      • Plater guy is supposed to be here today with the light so I will ask him then.

View attachment 641238
You are not going to get black algae that quickly.

Get through your 30 day startup and see what the plaster guy says.
 
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@PoolStored @ajw22

  • Standing down on the CH increase. I read minimum 200 and read that as free to go to the ideal target range.
    • My CSI is 0.07.

  • Regarding tabs, I guess what I am asking is, is it harmful? Its easy enough to measure the Cya and I know its about 6 ppm per tab. My plan is just to do this until im up to around 40 to 50 cya and my chlorine isnt vaporizing the instant i put it in the pool. I will add more to the sock, but for now with what's in the pool I know I can't exceed 40 on the cya even if the tabs dissolve completely between now and then. I am also trying to manage this with a trip headed out of town for a couple days which complicates things given my partner's inclination to work on the pool.

  • Also just following up on the light install. Should i hold off on that for the month to keep metal out the pool?
 
Why? 200 is what is recommended on the npc. 250 is just fine. Don't add more.

What is your CSI? In pool math, upper right gear, enable track CSI and track Temperature, and at the bottom enable sharing with TFP. Use your TFP login/password. That way we can see your logs.
A positive CSI of up to +0.5 is desired for the best plaster curing during the start-up.

The normal CSI guidelines do not apply to new plaster finishes under 30 days old. It is necessary to achieve a smooth and dense surface to have about a +0.5 CSI during the first 30 days. This is because the plaster (cement paste) surface contains about 20% calcium hydroxide, which is somewhat soluble in balanced and slightly positive CSI water and can be dissolved away. The plaster surface must be "carbonated" before the CSI is lowered to the acceptable and balanced range. That is generally achieved during the first month under balanced water.

 
Any CH of 250 - 650 is fine. I wouldn't add more than 250 at this point. Test your fill water (hose or whatever you would use if you had to add water) for CH and report that.
You want a higher CSI... ajw22'd
.
Tabs are acidic and will affect your pH. I would rather you control pH and TA with acid per the NPC. You have no idea if the tabs will increase FC above your 3 target or not.
If you have to manage a trip, then go ahead and use the tabs, likely the best option you have. I'd make sure you use a floater, and I'd make sure you tie it off with string or something else so that the floater does not sit next the side of the pool. The acidic water may affect the plaster cure. You want it in the middle of the pool.
 
@PoolStored @ajw22

  • Standing down on the CH increase. I read minimum 200 and read that as free to go to the ideal target range.
    • My CSI is 0.07.

You want to get your CSI up a bit higher.

  • Regarding tabs, I guess what I am asking is, is it harmful?

Yes, since you cannot tightly control the acid added and its effect on pH, TA, and CSI.

  • I am also trying to manage this with a trip headed out of town for a couple days which complicates things given my partner's inclination to work on the pool.

For a couple of days you can put tabs in a floater.

Liquid chlorine does not vaporize the instant you pour it into the pool.

  • Also just following up on the light install. Should i hold off on that for the month to keep metal out the pool?
There is no reason not to install the light. I do not know where you got the idea that you could not have the light in the pool.
 
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So just for reference. I added chlorine this morning to 3 ppm. with the floater. I just checked and the 10 ml chlorine test is barely pink so a small fraction of a ppm left even with the floater. Do I add chlorine 2 3 times a day or just once??

my pH was 7.4 and alk was 80+ at the same time.
 
So just for reference. I added chlorine this morning to 3 ppm. with the floater. I just checked and the 10 ml chlorine test is barely pink so a small fraction of a ppm left even with the floater. Do I add chlorine 2 3 times a day or just once??

my pH was 7.4 and alk was 80+ at the same time.
So I am tinkering with the CSI calc and even if i put 200 CH in the CSI calc it drops from -0.12 to -0.29 with those #s I am very confused. The only things i can do to get the CSA to plus 0.5 are to raise the pH, Raise the alk and Raise the CH with pH having the most dramatic effect and being way outside the range of the NPC recs.
 

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So I am tinkering with the CSI calc and even if i put 200 CH in the CSI calc it drops from -0.12 to -0.29 with those #s I am very confused. The only things i can do to get the CSA to plus 0.5 are to raise the pH, Raise the alk and Raise the CH with pH having the most dramatic effect and being way outside the range of the NPC recs.
Let your pH get to 7.8 to raise your CSI.

NPC sets up a puzzle that is almost impossible to solve.
 
Ok. Ill add some soda ash. Thanks. A mystery wrapped inside and enigma this NPC instructions. I guess you are supposed to replaster pools when its hot outside.
Do not add soda ash.

Just let your pH drift up.

  • Baking Soda = big TA change, small pH change
  • Borax = big pH change, small TA change
  • Soda Ash/Washing Soda (Sodium Carbonate) = big pH change, big TA change. Probably more TA change than you want. It is never recommended for use.