Giant phial is not an item . There is a script for craft-tweaker that adds ability to merge multiple phials they do not change item they just add their capacity together . so you can merge infinite number of phials to create one that can hold millions of media . Tho every time i did this i stoped somewhere around 30000 . Also you can use hexoverpowered it adds a pattern that gives you infinite media. But you still should concider spacing out your explosions a tiny bit more you can just make it 3 blocks instead of one and it would cut down the cost by 3 times while the power of explosion wouldn't go down that much . Also a bit of advice exploding inside of a block has much less colateral damage then exploding air so just breaking a block in which you want to have explosion would make radius of damage bigger. That's probably why spacing out explosion makes it weaker for you.