so in the config I want the blood moon to happen every 7th day in MC

schedule {
# The chance of a bloodmoon occuring at the beginning of a night (0=Never;1=Every night;0.05=5% of all nights)
D:Chance=0.01

# Whether there should be a bloodmoon whenever there is a full moon
B:Fullmoon=false

# Every nth night there will be a bloodmoon (0 disables this, 1 would be every night, 2 every second night)
I:NthNight=0

}

The problem is how do i configure the first line of "The chance of a bloodmoon occuring" to allow the "Nth night" code to work properly. Currently, if i set the chance to "0" it will never spawn in the world voiding the nth night spawn chance. if i set the chance number to a value it will happen to spawn on the nth day and possible other days which i dont want.

Setting the chance to 0 doesn't prevent the nthnight option from working for me. How exactly did you test this?

it would make sense to set it to 1.
100% of days masked by every 7th day