The Taylor K-1716 iron test is used if you strongly suspect the presence of iron in your water.  If you water source for your pool is community water, it is unlikely you have iron in it.

If your water comes from a well, then you have a  much better opportunity for iron in your pool.  Iron can be noticed with staining on pool surfaces (usually brownish) that are very difficult to remove. It can also be present in it's soluble form and the pool water will be perfectly clear.