Alkalinity Up?

[mackeeg]

The pool store said to add 3 pounds of alkalinity up today. Would that be 3 pounds of baking soda?
Thanks

 

[DavidD]

Yes, baking soda will raise alkalinity. I'm always skeptical of pool stores and their employees so don't add all at once. Add a little and re-test. I have encountered very few that are even remotely competent. Too bad there aren't many Evan B.'s (waterbear) out there . What is your alk and other readings? How many gallons? Type of pool?

Dave

 

[mackeeg]

The sheet says
FAC 5
TAC 5
PH 7.2
TA 90
Cal. H 120
CYA 100

above ground 18 foot 7500 gallons

 

[JohnT]

Your alkalinity is fine, but your CYA is too high.

 

[DavidD]

As Carl D. says, you have been "pool stored" my friend . With an alk reading of 90ppm, I wouldn't add any alk unless you are fighting a low pH problem. In other words, unless you are constantly having to raise your pH. Right now, I'd add a cup of Borax (20 Mule Team found at the grocery or Wal-Mart) to raise the pH and retest. Keep an eye on it and if it keeps going back down, raise the alk by adding a little baking soda. the ideal range is 80 - 100 ppm.

Dave

 

[DavidD]

Your alkalinity is fine, but your CYA is too high.

On a separate note, I agree with John but would add "for me" at the end of his statement. Your FC is 5 ppm and this is a little low for 100 ppm of CYA. You have two options:
1 Do some partial draining and refill to lower CYA. Most feel the ideal range is 30-50 ppm.
2. Keep your FC higher, 8 ppm MIN. per the chart below. Stop using Trichlor (3" pucks) and/or Di-chlor (Shock) since both of these add CYA.

Ben's 'best guess' FC/Stabilizer table for algae free operation of OUTDOOR pools
-- as of July 2003 --

Stabilizer . . . . . . Min. FC . . . . Max FC . . . 'Shock' FC
=> 0 ppm . . . . . . . 1 ppm . . . . . 3 ppm . . . . 10 ppm
=> 10 - 20 ppm . . . . 2 ppm . . . . . 5 ppm . . . . 12 ppm
=> 30 - 50 ppm . . . . 3 ppm . . . . . 6 ppm . . . . 15 ppm
=> 60 - 90 ppm . . . . 5 ppm . . . . . 10 ppm . . .. 20 ppm
=> 100 - 200 ppm . . . 8 ppm . . . . . 15 ppm . . .. 25 ppm

Quite frankly, there is nothing realy wrong with a high CYA, only as long as you understand that your chlorine must be maintained at a higher level in order to prevent algae and keep your pool properly sanitized. Agian, "I" keep mine lower. Also, as usual, I'll give you the priceless advice of getting a good drop based test kit that utilizes the FAS-DPD Powder system of chlorine testing. Dave S. sells one on this site or you can buy the more expensive Taylor K-006. Either way, do your own testing to avoid being "pool stored" in the future.

Dave

 

[mackeeg]

We just filled it with city water 1/2 way up this week. I wonder way the CYA is SO high then? I'll add a little Borax.
Thanks

 

[JohnT]

We just filled it with city water 1/2 way up this week. I wonder way the CYA is SO high then? I'll add a little Borax.
Thanks

If you haven't added any, then it might not be. CYA only comes from pool chemicals. If you've used trichlor or dichlor pucks or shock for several years, it could be pretty high, but you may be getting bad test results. None of your numbers are far enough out to be in a huge hurry to add anything. I'd go to Walmart and get their $15-ish test kit and run the numbers yourself, or go to a different pool store with a sample. I'd also recommend you get the test kit at www.tftestkits.com for better results and a wider range of testing ability.

 

[DavidD]

We just filled it with city water 1/2 way up this week. I wonder way the CYA is SO high then? I'll add a little Borax.
Thanks

Only Two possibilities as city water has 0ppm of CYA:
1. The pool store has given you an inaccurate test
2. Your CYA level from last year was approaching 200.

Either one or even a little of both is likely.

Dave