These pucks are odd ducks

[Rocket J Squirrel]

I accidentally bought these tabs at Ace Hardware not realizing they weren't pure trichlor. I have no idea what 3.5% zinc sulfate monohydrate will do to my pool water, and I've never seen this ingredient in tabs.

Is zinc bad simply because it's a metal? Or is it more of a salt in this form? These tabs were very expensive so I'd like to use them once in a while to supplant LC when I'm out of town, but not at the cost of polluting my water.

Thumbs up or down?

 

[ajw22]

I don't think zinc accumulation stains pools the way copper and iron do.

I would be more concerned with the accumulation of sulfates in the water.

Problems sulfates can cause include:

• Sulfates can damage concrete & plaster
• Excess sulfates in water increases the likelihood of corrosion on metal parts
• Excess sulfates in splash out water leads to degradation of any concrete surfaces
• Sulfates degrade the coatings on SWG plates
• At high enough concentrations, sulfates can react with calcium to form spindly, needle-like crystals of calcium sulfate (gypsum)

Chem Geek commented on it here...

Snake Oil - Can I get an opinion?

The local AM garden guy is pitching this stuff. http://www.crystalclearchems.com/ Cupric Sulphate Pentahydrate, Zinc Sulphate Monohydrate Looks to me like an algaecide. I am planning to send him an email directing him to TFP and the hazards of blindly dumping chemistry in. Hopefully I can...

www.troublefreepool.com

Let's see what @JoyfulNoise thinks.

 

[JoyfulNoise]

It’s a mild bacteriostat and it also acts as a floc. However at the pH of those tabs and pool water, it’s effectively useless. Just a filler so they can use less trichlor per puck.

 

[Rocket J Squirrel]

So OK for occasional use? I dose manually with LC and use pucks only when I'm unable to be there to lug a jug.