I need reassurance

[Marqoid]

I have been doing the TFP method for ~18 months with good results.
I have 15k in ground plaster. My CYA has been ~100 and reducing since beginning TFP. I have been maintaining 10 ppm chlorine and needed to shock twice to 30 ppm in the past year when I neglected to monitor chlorine.
I use k-2006 to test, but take a sample to my pool store to let them check my CYA. Eveytime they tell me that my chlorine is way too high and unsafe for swimming and unsafe for my equipment, but they insist that 100ppm CYA is appropriate. I hate to think that I understand pool chemistry better than my pool store owner after reading TFP method and forums for a few hours, but their recommendations are contradictory to my understanding of chemical interactions. This past time they even told me that it would be illegal to tell me that my pool was safe.
Am I missing something?
Does the chlorine sanitization effectiveness as related to CYA level also relate to corrosive effects on equipment?

 

[jblizzle]

Welcome to TFP!!!

Sorry to have to tell you, buy you indeed know more than the pool store owner.

All too often they seem to only get their chemistry knowledge from the chemical companies looking to sell stuff. And are wrapped up in the outdated EPA water recommendations that pertain to drinking water, not pool water. The FC/CYA relationship was proven in the 1970s and yet the pool industry continues to ignore it ... maybe out of ignorance, maybe out of desire for profit?

Simple solution is to just avoid the pool store and trust your own test kit (which is likely better than what the pool store uses).

10ppm of FC in 100ppm or CYA is equivalent in effectiveness and harshness to 3ppm of FC in 30ppm of CYA ... it will not hurt your equipment or you.

 

[Marqoid]

Excellent.
I'm still confused because I only go to the pool store to buy liquid chlorine, but when they test my water they tell me I don't need to buy so much chlorine. So they must not be too interested in profits, just unaware.

I thought it was funny that I showed them the CYA/chlorine chart and their response was "I've never heard of TFP and wouldn't trust it."

This site is a great resource, thanks.

 

[Donldson]

This past time they even told me that it would be illegal to tell me that my pool was safe.

Lol, reminds me of the old mechanic trick, "Legally I can't even let you drive out of here with your car like that." And just the same, 100% lie. There is zero legal regulation of advice given for residential pools, otherwise chlorine-free system salesmen would all be in jail.

Don't let them test your water. Confirming your testing with a pool store is like using a sundial to verify an atomic clock.

 

[pinguy]

If you are really interested in the science behind the FC/CYA ratios recommended here, there is a really deep rabbit hole to jump down here: Pool Water Chemistry.

 

[Texas Splash]

 

[Piolin]

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