Wrong Colors !?!

Problems relating to pH and total alkalinity.
Increase ph, increase TA. Reduce pH, reduce TA.
pH chemistry advice and techniques for the pool.
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Wrong Colors !?!

Postby JPlunket » Mon 13 Apr, 2009 07:34

Diluted another quarter late yesterday, refilled and heated overnight, thinking I should bite the bullet, get CYA down ASAP to save on bleach usage. But I stopped at a quarter down, realizing I could just accept higher bleach needs for now, until the sun/weather gets hot enough to raise my water temp above where we like it --then we'll get double-duty from dilution.

Water is crystalline, does not block the black dot without the reqgents added.

Would a pool store be able to get a really accurate CYA reading if I brought them a sample? I'd still like to make 100% sure I'm using enough chlorine to avoid the dreaded Yellow Algae or the like.

Related Qs --I use the "Nature2" cartridges, which are touted as lowering to 0.4ppm the chlorine level required for proper sanitation. First, do you accept this claim for the product? Second, will high CYA affect the functioning of this product? Third, is it possible to determine an adjustment factor to apply to the Chlorine/CYA chart at Pool School, related to the use of Nature 2?

chem geek
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Wrong Colors !?!

Postby chem geek » Mon 13 Apr, 2009 10:17

If the Nature2 cartridges are adding enough copper to the pool to kill algae, then they will be effective, but that level of copper is also enough to stain the pool if the pH goes up (it can also turn blond hair greenish). Usually in a pool, Nature2 systems are too weak and don't add enough copper, but your pool is smaller so perhaps it's been sized correctly.

High CYA should not be affecting the functioning of that product. You did notice that you got algae, which makes sense given the relatively ineffective chlorine level (low FC/CYA ratio), though if the Nature2 was putting out enough copper you should have prevented algae anyway. Perhaps they have it set lower to prevent staining so it helps reduce the rate of algae growth but doesn't stop it on its own without a certain level of chlorine.

It's hard to have an adjustment factor to the Pool School chlorine/CYA chart for Nature2 because, at least for algae prevention, it depends on the level of copper in the pool. With sufficient copper levels, algae growth can be stopped even if there is no chlorine in the pool, but such copper levels can stain the pool, especially if the pH rises. There are other ways of inhibiting algae growth including weekly use of PolyQuat 60 algaecide or use of a phosphate remover. These don't have the side effects of copper staining, but they, like Nature2, are extra cost. Of course, managing the FC/CYA ratio is a way of preventing algae growth using chlorine alone, but can be more frequent maintenance.


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