Key    : D
Standard EADGBe tuning

I think they omit the C# bass in the third verse.

Verse 1
D5
Oh crimson flow once shed for me
                         A5
My life I owe my saving King
               D5             
His blood has paid my ransom fee
Oh crimson flow that set me free

Chorus
D5
Oh the blood of Christ
                  A5
Oh the blood of Christ
D5                B5
Oh the blood of Christ
     G5     A5   D5
It washes over me

Verse 2
Oh crimson flow this solemn creed
That in my life I must decree
To tell the lost His Word and deed
Power to live in Christ our King

D5   A5   G5   A5  D5

Verse 3
Oh crimson flow the scarlet key
By which my soul at last shall see
The King above in all glory
With God most high I'll ever be