PhenoMenal
Well-Known Member
can somebody good with maths please check if my calculations are correct? I'm pretty ordinary with maths so struggled with this all day trying to get it right but i think i'm there now 
this is just to determine how much water to add to a res to lower its EC to a target
I know this is the basic calculation for when the topup water is EC=0.0:
New res volume = ((CurrentEC x UnitsOfWater) / TargetEC)
eg. to go from EC=3.0 to EC=2.0 in a 10L tank would be:
New res volume = ((3.0 x 10) / 2.0)
and from that i get 5 ("add 5 liters of EC=0 water to go from EC=3 to EC=2")
BUT my water is EC=0.5, so Im trying to adjust for that.
I think I've got it, but not 100% sure...
New res volume = ((CurrentEC x UnitsOfWater) / (TargetEC / (TopupWaterEC+1)))
eg. New res volume = ((3.0 x 10) / (2.0 / (0.5 + 1)))
and from that I get 12.5 ("add 12.5 liters of EC=0.5 water to go from EC=3 to EC=2")
If i set TopupWaterEC=0.0 i get the correct original answer so it seems ok from that test, but am not sure about >0
this is just to determine how much water to add to a res to lower its EC to a target
I know this is the basic calculation for when the topup water is EC=0.0:
New res volume = ((CurrentEC x UnitsOfWater) / TargetEC)
eg. to go from EC=3.0 to EC=2.0 in a 10L tank would be:
New res volume = ((3.0 x 10) / 2.0)
and from that i get 5 ("add 5 liters of EC=0 water to go from EC=3 to EC=2")
BUT my water is EC=0.5, so Im trying to adjust for that.
I think I've got it, but not 100% sure...
New res volume = ((CurrentEC x UnitsOfWater) / (TargetEC / (TopupWaterEC+1)))
eg. New res volume = ((3.0 x 10) / (2.0 / (0.5 + 1)))
and from that I get 12.5 ("add 12.5 liters of EC=0.5 water to go from EC=3 to EC=2")
If i set TopupWaterEC=0.0 i get the correct original answer so it seems ok from that test, but am not sure about >0