Quote:
Originally posted by CoolROD
In Althornin's spreadsheet:
for "% Kill-off Per Day" we have the formula:
=(1-A2^(K5*60*24/I9))*100
If 24 is the number of hours in a day -->and I change it to a 5
--> =(1-A2^(K5*60*5/I9))*100
I still get a result of 99.5763325 effective sterilization in 5 hours.
Al. -Is this correct?
Now I have no idea how often to run this thing. I would definately run it for the first 48 hours, though. And then, what, weekly for a few hours?
I don't want to have to run it unnecessarily...a few extra BTUs, bulb life, etc.
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The formula for kill offper day is simply
surviveability^(flow rate in Liters per min * mins per hour * hours per day / system volume in liters)
this however, gives an overall surviveability, so we subtract it from 1 to get kill off, and times 100 to get percent.
now, the interesting part is in the s^(blah blah) part:
look at units:
liters*mins*hours/mins*hours*days*liters
it gives cycles through system per day...
The thing is, with a 10liter per minute flow rate and maybe a liter of volume, you pass each bit of water through the UV light 600 times per hour
So if only 1% dies each hour, thats .99^600, which is .0024, and so per hour, almost everything is killed off.
you have to realize, these things are DESIGNED to deal with a good flow rate (but not even 10 liters/min - 7.6 for the 4 watt device) but HUGE tank volume, meaning water only sees the inside of the device like two times per hour! So in our case, we are running water through it 300 times more often than it needs....
Quote:
Power / max gph / Max tank size (g)
4 W / 120 / 75
8 W / 180 / 150
15 W / 450 / 300
30 W / 750 / 500
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en these maxed systems, each bit of water runs through less than twice per hour! so yes, even 5 hours on could easily kill damn near everything... its the same effect as running those things in a tank at max spec for like 1500 hours
ah yes, slightly updated excel file, all i added was common unit conversion spaces (gallons to liters and inches to cm) just for ease of use. hopefully its more than just you and me reading this stuff, CoolRod.