Magic the Gathering???

Question

Actually My question Is On a Specific Card Called Shimmering Grotto I Don't get It's effect Completely.The card Effect Say's That When it's Tapped Add One (Meaning Any mana) To My Mana Pool But Under it It Say's

1,Tap,Then i can Add One Mana Of Any color To My Mana Pool.

1.Why Does It Say that If I can Add any One Mana By Just Tapping Why would i tap One of my mana Does it mean i can tap one of my mana and add an extra to my mana pool making it two mana per turn if i don't draw a land

2.Can i use shimmering grotto's effect to put another shimmering grotto in my mana pool

Answer 1

Shimmering Grotto can add 1 colorless mana to your mana pool when it's tapped.  If you pay 1 colorless and tap Shimmering Grotto, it turns that 1 colorless mana into a mana of any color.  It's Chromatic Sphere as a land with the sacrifice cost.

Answer 2

( 1 ) does not mean any color mana.  It means 1 COLORLESS mana.

Colorless mana has no color and can't be used to pay costs requiring a specific color.

For example if you have a spell which costs 2GG ( where G = the green tree mana symbol ), you would need to generate 2 mana from sources which SPECIFICALLY generate G ( the green tree mana symbol ).

In this case you could tap your grotto to pay for 1 of the 2 generic mana costs in the spell, or you could pay 1 generic mana and use it to generate a G.

And yes, lands count towards effects based on number of permanents.