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Lastest water test at local pool store:
CYA 168
TC 0.6
FC 0.6
pH 6.9
TA 126
TH 527
TDS 2100
20,000 gal, in-ground gunite
Cartridge filter
We are having to shock every week. We are currently stuck in that "Bioguard is the best" trap. We use the Smart Sticks in our skimmer and the Bioguard shock products.
Ubalr, welcome ot the forum! Your numbers are certainly from a pool store, honest folks who do their own testing get numbers that end with "0". Your cya and hardness results make a partial draining a good idea, but only if the fill water is lower in calcium. My best advice is to get a good test kit and learn how to use it, take control of your pool. Your pH is way low, dump a box of Borax in ASAP, and a couple gallons of regular (unscented) bleach in the pool -NOW (with your cya so high, you need a lot of chlorine) I'm sure that others who know more about the chemistry side will post, but do what I'v said as soon as you can. Good luck with the pool, you can escape the Biocrud cycle if you take matters into your own hands.Quote:
Originally Posted by ubalr1
Thanks Waste. Not sure I understand this "honest folks who do their own testing get numbers that end with "0"." We do have our own tester that we use on a sporadic basis. Our numbers are in the ballpark with the pool store. We just added 12lbs of sodium hydrogen carbonate (aka., soda ash, baking soda, sodium bicarbonate). We'll see what that does. The water in my area is very hard (19-20 grains, ?ppm). So, I am thinking of switching the auto-fill supply from hard water to soft water. I should have done it summer before last when we drained the pool. Still considering (researching) the whole liquid bleach approach.Quote:
Originally Posted by waste
BTW, from what I find online, Borax and soda ash are not the same thing. Does Borax (also called sodium borate or sodium tetraborate) do the same thing chemically in the pool as Soda Ash (also known as sodium carbonate, sodium bicarbonate, sodium hydrogen carbonate)?Quote:
Originally Posted by waste
Never mind. I'm learning as fast as I can - the more I read through this forum. Add Borax to raise pH. Add soda ash to raise total alkalinity. Both problems (low TA and low pH) that I have according to my numbers. Right?
Ubalr1, I believe that every new poster deserves a quick response, even if I can't provide the 'full' answer. There are folks here who understand chemistry MUCH better than I. What I know has been (mostly) gathered from reading a bunch of threads here, so I'm passing on second hand info to you.Quote:
Originally Posted by ubalr1
As for the 'results ending in '0' ', pool store testers seem to have a 'built in' 'sell chems' sub program in them, when I do a drop based test (like Ben's kit or the Taylor 2005 kit) I get results that are in increments of 10 - a pool store number that doesn't end in "0" is an indication of the 'selling software' kicking in. (this does not apply to cl or pH)
While we're at it soda ash (a/k/a sodium carbonate/ soda ash is different from sodium bicarbonate (a/k/a sodium hydrogen carbonate) The Borax is a different way of raising the pH, but it doesn't affect the total alkalinity like soda ash does.
I hope that this is at least slightly helpful, I'm thinking that a few of the folks who know more about chemistry will post when they see it.
Very helpful. Thank you.Quote:
Originally Posted by waste
Waste is right on the money with his answer about soda ash vs. borax!:D
Soda ash will increase pH and TA at the same time which, usually is not desirable. Borax will have minimal impact on the TA while raising the pH. The reasons are pretty technical and really of interest only to chemical nerds like myself.:rolleyes::D
If you need to increase the TA don't buy the 'sodium hydrogen carbonate' from your (I am assuming) Bioguard dealer at the pool store. It is most likely commercial grade. USP grade (which is much purer) can be had at the grocery store for less money as Baking soda!
If your pool store is using a colorimeter for testing with liquid reagents then it is possible that your numbers won't end in a 0, BUT if they don't calibrate the instrument on a regular basis then the readings might be less accurate then those from a test strip. IF they are giving you a computer printout either the meter is hooked up to the computer or they are manually entering the numbers, either way the clerk can (and sometimes do, I have seen it) change the numbers before the printout is run. You never know. If they are using strips with a meter I would suggest to RUN and NOT WALK out of there and not believe the results. Get in the habit of doing you own testing and take control of your water. You will be glad that you did! (And yes, I DO test water for people all day at work and sell chemicals!)
[QUOTE=ubalr1]Lastest water test at local pool store:
CYA 168
TC 0.6
FC 0.6
pH 6.9
TA 126
Adj TA 76
TH 527
TDS 2100
20,000 gal, in-ground gunite
Cartridge filter
Ahhh! This is confusing. What is the defference between Total Alkalinity (TA) and Adjusted TA. What I forgot to post originally was the Adj. TA as calculated? by the pool store. Adj. TA was 76. Which should I really be using to make adjustments.
I found this formula online:
Adjusted TA = TA - (Stabilizer X Stabilizer Factor)
with
Total Alkalinity Adjustment Factors:
PH____Cyanuric Acid Factor
7.0____0.22
7.2____0.26
7.4____0.30
7.5____0.32
7.6____0.33
7.8____0.35
8.0____0.36
Following this formula (and extrapolating for my pH since it's just off this chart)
I get an Adj TA of 90.72 (not 76 like the pool store)
Adj TA = 126- (168*.21) = 90.72
We're heading back to the pool store for another test since we added 12# of sodium hydrogen carbonate yesterday. Our test kit fo TA indicates not much change in TA.
Things are improving.
. . . . . .28-May. . . 29-May*
CYA. . . .168. . . . . 110
TC. . . . . 0.6. . . . . 0.7
FC. . . . . 0.6. . . . . 0.7
pH. . . . . 6.9. . . . . 7.2
TA. . . . . 126. . . . .161
Adj TA. . .76. . . . . 128
TH. . . . . 527. . . . .450
TDS. . . . 2100. . . .2100
After 12# of sodium hydrogen carbonate. Adding chlorine now.
Hi ibalr1 :)Quote:
Originally Posted by ubalr1
glad you found the forum...hope you find it as useful as I have.
I am a total pool noobie...so I'm asking for clarifications sake>>>
How did you get your CYA to drop 58 points in a day?
did you get the sample done at the same places? (no matter if with the same test kit...or from the same store)
Did you partially drain and refill your pool?
I suppose that's my largest question...
thanks,
dan
Same pool store, same pool guy. The only things we did between samples are:Quote:
Originally Posted by gonefishin
- remove solar cover (temp of pool on 5/28 was 92, on 5/29 it was down to 86)
- add 12# sodium hydrogen carbonate
Your question is intriguing, since all I have read in the last couple of days regarding CYA says the only way to lower it is by draining water and replacing it with fresh.
Frist, the difference in your CYA readings is from operator testing error. NO doubt in my mind about that! There is NO way that taking your solar cover off and adding baking soda (which is what sodium hydrogen carbonate is) will lower your CYA! The CYA test is the easiest to get bad results from sloppy testing. Get a test kit and test it yourself!
Second, Total alkilinity vs. ajusted Total Alkaliniy....The amount of CYA in the water will have an effect on the alkalinity reading. The CYA will show up in the TA test and make it read higher (your Ph at the time of testing will have an effect on this and possibly on the TA reading also). If you CYA levels are very high this can cause your TA to read a bit higher than it actually is for a giving pH (higher than the actual amount of carbonates/bicarbonates in the water). Many people don't feel this correction is really important. IMHO, unless your CYA levels are very high and your TA is at the very low end of the accepted range it really isn't that important as your own numbers show the trend. If your CYA is in the accecpted range of 30-50 ppm this correction has very little impact on the TA reading for a given pH. Also get your pH in line first since this has an effect on both the TA and adjusted TA as you saw in your own research!
Just decide if you want to use TA or adjusted TA and stick with it once everything else is in line. I personally just use TA on my own pool because I am too lazy to do the math and my numbers are still in range when I make the correction! I think you will find the same to be true once you get everything balanced.
My advice would be to lower the CYA by a partial drain and refill and then retest. Also, get a good test kit and start doing your own testing. It's really easy.