General order of operations, CYA <20, my initial measurements and why no algaecide?

#1
General order of operations, CYA <20, my initial measurements and why no algaecide?

First, thank you for the great work you guys do! :D I'm a reformed chemist and always knew the ingredients in the pool store chemicals were common household chemicals that I could get for a lot cheaper. I just didn't have a resource to provide the numbers/calculations for proper dosing.

First, the measurements:
pH: 6.8
FC: 7.5
CC: 0.5
TA: 55
CH: 125
CYA: <20

Second, the story:
I pulled the cover off the pool yesterday and it looks great! Clear water with just a tiny layer of green algae on the bottom. I had to add a lot of water from the well to get it to a proper operating level. The well water is slightly acidic and slightly hard (I don't have exact numbers for that). I added a gallon of 10% liquid bleach just for good measure until I could get the filter going and get measurements today. I got the pump and filter going this evening, stirred everything up by scrubbing the bottom surface of the pool with the vacuum head and then waited 30mins and got the above measurements.

I am familiar with the pool calculator, so I'll get my numbers into that but I have a couple of questions:
  1. What is the general order of operations for chemical addition? I just haven't found any exact instructions on the site as far as something like the order that is on all of the pool chemical labels: 1. Stabilize the pool with CYA 2. pH balance the pool. 3. Add chlorine
  2. My CYA was not measurable with the T100 kit. It is far less than 20 as the black dot was still super visible but the water was slightly translucent. How should I add the CYA to not overdo it?
  3. I haven't seen any mention of algaecide or clarifier on TFP. Why not? Is it because, if one does it right, one does not require either?

Thank you for your help and any additional recommendations that were not addressed by my questions.
 

jblizzle

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May 19, 2010
41,197
Tucson, AZ
#2
Re: General order of operations, CYA <20, my initial measurements and why no algaecid

:wave: Welcome to TFP!!!

There is no flow chart because every story seems to be a little different ... and honestly the order does not really matter.

You want to get your CYA up to about 30ppm to start with ... so maybe add 20ppm initially (in a sock dissolving in front of a return jet).

After you got the sock in the water, you need to get that pH up with borax or soda ash and keep it in the 7s. Actually given that your top off water is acidic, you might just raise the TA up to about 70-80ppm with baking soda and then retest your pH in an hour or so.

Once the pH in the 7s, then start to follow the process assuming your CYA is around 30ppm (you can speed the dissolving by squeezing the sock a bunch of times).

If you maintain the correct FC/CYA ratio ([FC/CYA][/FC/CYA]), then there is no need for any algaecide or clarifiers or magic potions.
 

AimeeH

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Apr 2, 2012
1,998
Columbia SC
#3
Re: General order of operations, CYA <20, my initial measurements and why no algaecid

HI there :)

I hope I can answer your questions. You're familiar with pool math so first adjust PH up to about 7.2 (washing soda or borax).

You'll want to raise your CYA to a target of about 30 before proceeding to follow the SLAM process Pool School - SLAM - Shock Level And Maintain

We reccomend adding CYA by putting the granulated form in an old sock and hanging in front of a return to help dissolve.

We don't generally reccomend Algaecide because by and large they are a preventative not cure and so many add copper to the pool which is simply an undesirable and can lead to staining.
 
#4
Re: General order of operations, CYA <20, my initial measurements and why no algaecid

Thanks for the help! Here's the progress so far:

Original #'s
pH: 6.8
FC: 7.5
CC: 0.5
TA: 55
CYA: <20

So I added:
Bleach: 0 gals
Baking Soda: 3lbs
Borax: 2lbs
CYA: 2lbs

And got the following measurements the next morning:

pH: 6.8
FC: 8.0
CC: 0.0
TA: 70
CYA: 25

So then I added, in an attempt to get the pH up without too much of a TA increase and to get the CYA to 30:
Bleach: 0 gals
Baking Soda: 2lbs
Borax: 4lbs
CYA: 0.5lbs

I have yet to measure this morning...

My question is why was there no measurable change in pH between the 1st and 2nd chemical additions? 3lbs BS and 2lbs Borax should do something. Is it b/c of the CYA addition and its corresponding lowering of pH? Or is it because the FC is high enough to disrupt the pH measument?

As a side note, the CYA in the sock in front of the return was great! 2lbs dissolved in ~12 hours with some massaging.
 

pooldv

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Aug 10, 2012
24,993
DFW, TX
#5
Re: General order of operations, CYA <20, my initial measurements and why no algaecid

Yes, CYA will lower PH. Toward the bottom of PoolMath is Effects of Adding Chems enter the amount and select a Chem and it will tell you what it will change in the pool. Sounds like your TA is getting too high, 60-70 is good. More here, Pool School - Recommended Levels

FC only interferes with pH test above 10ppm.
 
#6
Re: General order of operations, CYA <20, my initial measurements and why no algaecid

Sounds like your TA is getting too high, 60-70 is good. More here, Pool School - Recommended Levels
The link says 50-90+. Are there any issues with high TA? I didn't have enough borax to do the entire 2nd chemical addition in borax so I used some baking soda to help with the pH, knowing that it would continue to raise the TA.

When do the reagents in the TFP-100 kit expire? My kit is left over from last season.
 

jblizzle

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May 19, 2010
41,197
Tucson, AZ
#7
Re: General order of operations, CYA <20, my initial measurements and why no algaecid

The higher the TA the faster the pH is pulled up. TF test kits warranties the test kit reagents for 18 months.
 

pooldv

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Aug 10, 2012
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DFW, TX
#8
Re: General order of operations, CYA <20, my initial measurements and why no algaecid

It isnt a big deal. The higher TA gets the more it will push up your pH. But, then adding acid to lower your pH will slowly lower your TA over time.

Taylor reagents are guaranteed for a year. If it is stored inside in a climate controlled area it will be good for this summer.

Edit: 18 mos? I need to read up! :)
 
#9
Re: General order of operations, CYA <20, my initial measurements and why no algaecid

So I measured tonight after the last chem addition last night and got:

pH: 7.0
FC: 7.5
CC: 0.0
TA: 80
CYA: 25

Only a 0.2 pH increase after adding 2lbs of BS and 4lbs of Borax? Is it still the CYA keeping it down or what else could it be? I am going to add 4 more lbs of borax to try to get the pH up again.

The good news is that my FC is stable. Do you still recommend the SLAM with stable FC levels ~7.5?

thanks again for your help!

 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
41,197
Tucson, AZ
#10
Re: General order of operations, CYA <20, my initial measurements and why no algaecid

So you added chlorine last night and tested up level of 7.5 PPM? And then tonight tested the same level? Because that is just not possible due to losses to the Sun.
 
#11
Re: General order of operations, CYA <20, my initial measurements and why no algaecid

No, haven't added any bleach for days, since the initial gallon I dumped in after removing the winter cover. I've just been trying to get the pH and CYA up to levels appropriate for a slam. I live in NH and have a solar cover on it and the water temp is in the 50's, so all of that helps reduce FC loss but, i agree, there should have been some loss.