CYA and the pool store reading

Mar 4, 2015
718
Sugar Land , TX
So I go to pool store about every 3-4 weeks just to double check myself ( probably first mistake ). About 3 weeks ago CYA was at 40ppm ( PS reading ) so I added enough to get to 50 ( hot Houston ). Yesterday went to PS and it read "0" ! PS guy asked if I had drained and refilled water ( no ). Asked if we had bad splash out ( no ). Asked how long I let pump circulate before getting sample ( 1 1/2 hrs like previuos ). He said I should let pump run 4 hrs prior to getting sample. I also said we have had alot of rain ( daily ) and my overflow might be causing loss of water. He said probably not since CYA tends to settle at bottom of pool and that is why the 4 hours of pump prior to sample. I have not read that before. Anyone know if this is true or not? Going to restest tomorrow
 
There is no truth in the idea that CYA settles, chances are their equipment was wrong.

ps I bet if you take the SAME sample to a different pool store you would get different results, you really need your own quality test kit and do your own testing
 
Yes get a kit, trust your own readings. Cya does not settle, it stays evenly distributed throughout the water column. Just last week, we had one saying it stayed on top providing "shade" for the Chlorine.

C'mon Pool Stores!!! :hammer:
 
Ordered my TF100. I know ..Why did you wait so long....

Went to pool store today after testing myself this morning.
So my test this am:
FC 3+ using OTO ( Stenner system )
pH 8.2 raised TA last week with A&H and it increased pH. added acid per pool math
TA 90 Right were I want it.

Pool store 1 hr later:
FC 0.5 This can not be correct 1 hr later. I have not been loosing chlorine like that.
TAC 0.5
pH 7.4 probably correct added 16oz. acid
CYA 10 this is after being 40 most of April-May and then as I mentioned above May 20th went to "o" and now they say 10 and I have not added any type of CYA. Goes to show you can not trust their numbers.

Can't wait to get my TF100 and get correct numbers.
 
Now you're getting it! :goodjob:


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Richard in your opinion, with all the rain we have had in Houston over the last months. Had 10 " Memorial day at our house overnight. Would that affect my CYA levels that much? I have read other threads about rain and it seems large volumes can affect it. We have auto overflow so I do not know how much dilution really takes place. Anyway the TF100 will let me know.
 
Richard in your opinion, with all the rain we have had in Houston over the last months. Had 10 " Memorial day at our house overnight. Would that affect my CYA levels that much? I have read other threads about rain and it seems large volumes can affect it. We have auto overflow so I do not know how much dilution really takes place. Anyway the TF100 will let me know.
You're asking the wrong guy about rain. We've had just under 9" since last October 1 !!

It's a straight progression. If you average pool depth is 50", 10" of rain will have reduced CYA and CH by 20%. How far has the CH dropped? If it matches the CYA drop, you know your reading is right.
 
Well that answers some questions since CH has not dropped at all. Either I have something in my pool eating the CYA, and if I do, I need to bottle and sale it so I can retire! LOL

OR the pool store can't get the reading correct. Which do you want to bet on?
 
If you discover that CYA eating "monster" you have, Your new pool will be so large there will be a MAJOR TFP party at your house. There's about a million Texans on this forum (all will be your new, best friends) who can be there in 24 hours.

I'll bet they missed the first one at 40 but I hope not. Anyway, you will soon know for yourself. Don't get frustrated by the ambiguity of the CYA test.....it gets easier after you do it a few times. Pour the solution back into the view tube over and over so you can get multiple "reads" from the same sample.
 
There is only one thing known to eat CYA, and that is a bacteria that converts it to ammonia. Well Ill restate, there is a second bacteria sold commercially, but it doesn't work well.

If you had the ammonia type, you would be going through all chlorine in less than an hour, which your not.
 

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UPDATE 6/12/15 Re: CYA and the pool store reading

Did my first test with TF100 this morning. Only had time to do quick OTO ( 2ppm) and first CYA ( 0 ). May have to eat crow here but it matched what pool store said. I guess 10 inches of rain over night plus all the other rain we had must had diluted or over flowed it out. So I think the excessive rain was my CYA eating monster!! I think this will be a good time to use up my pucks ( sorry for using the p word ) I purchased when pool was new. This should slowy add some CYA and my pH needs to lower a little also. I would like to get CYA back to 40-50 so pool math says 32oz trichlor ( #4 8 oz 3" pucks ) will raise FC to 26 and CYA to 16 and lower pH 1.38. So my question is what flow rate ( 1-5 ) should I turn my Pentair 300 feeder to? I assume 1 or 2 to slowly build up over a couple weeks. Any ideas?
 
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