Preaching TFP in the land of infidels--so is Cl an evaporant?

[Durk]

I´ve been visiting my ex- and kids in Brazil for the last month and the pool guy and I are having the predictable lack of understanding. He basically throws in an inadequate dose of Cal-hypo once a week (even though he comes Mondays and Thursdays) and makes up for it with cheap copper algaecide and flocculant. It was cloudy when I got here, and I gave it a quick fake slam (done by guess rather than testing, but it worked) and some 24-hour filtering, and cleared it right up. Maintained it perfectly with Cal-hypo every day for the past three weeks--all say it has never been so clear. But he is fighting me tooth and nail. Increased chlorine use and stopping algaecide will cost more and won´t work well, blah, blah. Meanwhile, decent testing equip./supplies beyond test strips and OTO/phenol red are unknown. The ´pros´ use basic Aqua-Chem strips.

Today, he throws a new one at me. Chlorine is an evaporant, he says, and higher levels increase water evaporation and thus usage. The city I am in, Itu in São Paulo state, is in a drought caused water shortage crisis, and this is a big deal. Is there any basis to this, or can I call chemical BS?

Pool is 100k liters, 35 year old 100% full-tile, 7m x 12m x 1.2m avg, big sand filter, 1.5 hp Pentair pump (Triton?) set to run 3hr/day, water sits at 80°F and air gets to low 90°s. Open all year. Brutal sun right now as right on Tropic of Capricorn.

TESTs: pH 7.5, CYA <40 but some (strips--gag), Cl 4.0 target, 1.0 pre-dose (what I did and worked), CH 200-300(strips again), TA 70-80 (likewise). CYA is there because they use powdered tri-chlor (yes, trichlor) and cal-hypo pretty much interchangeably. No pucks.

 

[JasonLion]

Not really, chlorine won't have any noticeable impact on water evaporating, either pro or con.

It is not the same thing at all, but this kind of reminds me of outgassing. Chlorine will outgas (leave the pool and go into the air), and if the FC level is very high it will outgas more quickly. However, this happens slowly enough that it is not a significant issue. And, of course, outgassing is not the same as evaporation.

 

[Durk]

Not really, chlorine won't have any noticeable impact on water evaporating, either pro or con.

It is not the same thing at all, but this kind of reminds me of outgassing. Chlorine will outgas (leave the pool and go into the air), and if the FC level is very high it will outgas more quickly. However, this happens slowly enough that it is not a significant issue. And, of course, outgassing is not the same as evaporation.

Thanks, Jason. He wasn´t talking about outgassing, rather a real increase in evaporation rates. Two buckets are now sitting on the pool edge, Cl=0 and Cl=12. We´ll see if A or B goes faster. It´s on, dude.

 

[duraleigh]

You will win, Durk....no doubt.

At some point they need to test CH and CYA. What is the average rainfall? (for dilution purposes).

 

[Shirker]

Just keep an eye on your control bucket!

 

[Durk]

You will win, Durk....no doubt.

At some point they need to test CH and CYA. What is the average rainfall? (for dilution purposes).

Normal years, enough to dilute down anything. Inch an hour type rain is common. Almost all Brazilian pools are built with overflow drains or they would overflow regularly. But this past year has been a record breaker on the dry side, in both wet and dry months. City reservoirs under 10% and they had odd day rationing (and worse) in the middle of last year. People had to buy from tank trucks for household use. Houses here use 1500-3000L gravity tanks even on city water.

In Itu, the climate is warm and temperate. There is significant rainfall throughout the year in Itu. Even the driest month still has a lot of rainfall. The climate here is classified as Cfa by the Köppen-Geiger system. The temperature here averages 19.5 °C. The average annual rainfall is 1279 mm.http://en.climate-data.org/location/10535/