chemistry questions for newb

[Shirker]

Test results (via TF100 kit)
FC: 2
CC:0
TA: 90
CH: 225
PH:7.5
CYA:<20*

Questions
1.) I read on this site that I should not add calcium (above ground). I started out with 0 and the pool store recommend that I add 25 pounds. I still have about 8 pounds left to add. Should I stop?

2.) My local pool store measured my CYA as 20. But I can fill the view tube completely and still see the black dot. Is the test sensitive to levels that low?

3.) I am using trichlor tablets with a feeder. I understand that this can cause my CYA to get too high. Should I try to keep my CYA low or should I add more now to hit the recommend level of 30 to 50?

Thanks in advance for all of your help. This site is great!

 

[Casey]

Hey Shirker.

#1 You have an above ground vinyl pool. You don't need Calcium. It is more for plastered and fiberglass pools. You got pool stored. Sorry to say.

#2 Pool Stores are notoriously wrong with CYA levels among other things. Trust your test kit. That's why you bought it right?

#3 Not only will the trichlor raise your CYA, it will make your pH and TA too low as it is acidic. To simplify things, you should get Stabilizer/Conditioner at WalMart, throw it in a sock over the return and dissolve it that way and call it a day. DONE! Then the only thing you'll need to worry about on a daily basis is your FC and pH.

 

[Abigail K]

Replies in red.

Test results (via TF100 kit)
FC: 2 2FC is the MINIMUM. Add chlorine.
CC:0
TA: 90
CH: 225
PH:7.5
CYA:<20*

Questions
1.) I read on this site that I should not add calcium (above ground). I started out with 0 and the pool store recommend that I add 25 pounds. I still have about 8 pounds left to add. Should I stop?
Calcium isn't needed in AG pool as there is no plaster to leach calcium. However, calcium accumulates (from topping up the pool esp. if you have hard water) and too much calcium can cause scaling. Some heater manufacturers require minimum calcium levels for warranty but this doesn't seem applicable to you - definitely stop.

2.) My local pool store measured my CYA as 20. But I can fill the view tube completely and still see the black dot. Is the test sensitive to levels that low?
If you could see the dot but it was cloudy, then you have some CYA but less than 30. So yes, it is sensitive to levels that low. Also, CYA takes up to a week to be detected.

3.) I am using trichlor tablets with a feeder. I understand that this can cause my CYA to get too high. Should I try to keep my CYA low or should I add more now to hit the recommend level of 30 to 50?
We do not recommend the use of trichlor for routine FC maintenance due to the reason you mentioned. Because you have a relatively fresh fill, it hasn't affected your water chemistry significantly. Use bleach/liquid chlorine to maintain your FC levels. If you know how many pucks you have used so far, you could input it into PoolMath "Effects of adding chemicals" to get a more accurate CYA level.

Thanks in advance for all of your help. This site is great!

 

[Divin Dave]

To add to what Casey and Abigal said,
first thing you need to do is get your CYA up so you can protect your FC. Your 2 ppm is going to burn off quick.
http://www.troublefreepool.com/content/160-pool-filter-comparison
http://www.troublefreepool.com/calc.html

 

[Shirker]

Thanks for the feedback. I thought I could trust the pool store guy. I was impressed that he told me *not* to buy the Alkalinity Plus from him and to instead buy baking soda from the grocery store next door. I guess I can just give him the benefit of a doubt and assume he did not realize I didn't need the calcium? Oh well.... I now need to find a cool science experiment with the kids to use up the unused portion.

My FC levels have bounced up and down (from 5 to 0 and now back up to 2). Trying to figure out how long I need to run my pump each day and at what setting for the chlorine feeder. Still researching but will probably switch over to liquid chlorine soon.

 

[Abigail K]

Maybe he didn't realise you didn't need calcium... Did he know what surface your pool is?
I'm half the planet away and not too familiar with US geography, but does it snow where you are? Because you can keep it for use as ice melt...

See also Pool School on how to determine pump run time.

 

[Shirker]

Yes, he knew I had an above ground with liner. Yes we get a little snow around here (1-2 inches {2-5cm} per year) but it is usually gone by lunch time.