If your pool is properly water balanced and has a pH near 7.5 (certainly greater than 7.2), then it is unlikely that the copper pennies will be a problem with either water balance or stains. Remember that the heat exchanger in a gas pool heater is probably copper and water flows through it whenever the pump is running (even when the heater is turned off). Also, consider that many homes use copper water pipes.
Metals will corrode (oxidize) in acidic conditions with the presence of dissolved oxygen though the actual factors are quite complex. Nevertheless, you should probably scoop out the pennies from the pool after your kids have had their fun, mostly for safety and aesthetic reasons.
Too many pennies(say a gallon of them or so) may cause green water if improper water balance but copper is a natural germ killer so no it can only be a benefit unless they get into your pump.
Remember that water is a solvent and can dissolve many things. Even if you have a "perfectly balanced" pool ( and realistically nobody does) those pennies will stain the pool -- they are not solid copper and have a mixture of other elements in them.
the most likely culprite is chemical or biological chlorine uptake. something in your water isn't allowing you to achieve break point chlorination ( the point at which you can measure free chlorine). This could be due to ammonia, sulfur, iron deposits or some other chemical in your sourcewater that is "eating up" your chlorine.
The chemical symbol of the halogen element chlorine is Cl.
Chlorine is an element.
Chlorine is "CL".
Chlorine is a chemical element.
No. Chlorine is a chemical element.
Chlorine is indeed a chemical substance, specifically one of the chemical elements.
The chemical symbol (not formula) of chlorine is Cl.
In the English language is chlorine.
The chemical symbol (not formula) of phosphorous is P; the chemical symbol (not formula) of chlorine is Cl.
There is no other substance in chlorine except chlorine, which is an elementary substance.
The chemical formula for carbon and chlorine is CCl4 (carbon tetrachloride).
The chemical formula of diatomic chlorine gas is Cl2.
The chemical symbol on the periodic table for Chlorine is 'Cl'.
The chemical symbol for chlorine is Cl. The symbol for sulphur is S.
Chemical activity increases as you move upward in the group. Chlorine gas and chlorine compounds have been used as chemical weapons
Chlorine is a highly reactive agent thus this indeed is chemical.
The chemical bond between chlorine and hydrogen is polar covalent.
The diatomic chemical formula of chlorine is Cl2.
Chlorine is a simple element composed of chlorine. It is it own chemical substance.
Chlorine is a chemical element and contain only chlorine atoms.
There is no chlorine chloride. A molecule of chlorine has the formula Cl2.
Chlorine iodide (ClI)