First time pool owner with lots of questions

Pool stores ALL look at calcium levels and if it's not between 200 and 400 they say "You need calcium". No, you don't. Calcium is, as you suspect, for masonry pools, because the concrete, mortar, plaster, and grout all are calcium carbonate and water will leech and weaken them unless there's sufficient calcium in the water. Vinyl? NOT an issue! :)

Magic additives sold by pool stores never work. Period. I never use them. Watermom never uses them, and most of our support team here never use them. The RARE times any of them might be usable, the owner, PoolDoc (Ben) can determine EXACTLY how to use whatever and what steps to take, but that is very, Very, VERY rare! 99.999% of the time they are a problem and do no good.

Thank you watermom and CarlD!

Yes I purchased the test kit.

Estimated delivery date of the testing kit is... Sept. 17, 2014 - Sept. 22, 2014

It's been poring all day today so far almost 6 inches has fallen just in the past 5 hours! it's crazy.. the pool is looking full, and I'm guessing I'm going to need to pour a lot of chlorine in or it's going to turn green again! today the pool looked light blue but still foggy.. i backwashed yesterday and cleaned the sand filter, hopefully it will start clearing up... of course this rain may change everything.

oh yeah.. a little more information on the pool... I looked at my pump and its a 3/4 hp pump.. the filters information is completely faded so no idea brand or size. if i get the 24 or 30 inch sand filter should i upgrade the pump to 1hp or 1.5 or not at all?

A 3/4hp pump is just fine. In fact, you don't want a too powerful pump. The equipment set ups that work best are larger filter paired with pumps that are not too big.

Watermom is right ( :) )! More horsepower is GREAT in cars, boats, motorcycles and lawnmowers--but not in pools! It just burns electricity and frequently overtaxes undersized filters.

Update on the pool today.. water is blue but still cloudy... do I just wait to see if the filter takes care of the cloudiness? haven't done much except shock with chlorine after the big rain so that it doesn't go green again. what does cloudiness mean when it comes to pools?

It usually means dead algae. Keep your chlorine high and run the pump 24/7 while you are trying to clear it.

OK so ran pump 24/7 through the weekend... water still cloudy, however it is less coudy than it was.. i can now see to the second rung of the latter, but it's a big couldy.. the top rung is crystal clear. at this rate, my water will be clear just in time to close the pool...