WC schedule maths

[rennjidk]

Sorry in advance. I've heard it said that a 1.5% daily water change will cause a plateau effect on build up of contaminants and elements after only a couple months. Where would a 0.5% daily WC plateau (assuming all additions are equal)? And how often for a total volume change over (within reason, not diminishing infinitely if it does)?

 

[rennjidk]

I realize that was probably poorly worded and may be confusing. Here's an article by Randy of what I'm referencing, only with 0.5% daily WCs.

http://reefkeeping.com/issues/2005-10/rhf/index.php#3

 

[Randy Holmes-Farley Verified Community Expert]

The article you have shows the effects.

See Figure 6, red line.

 

[rennjidk]

The article you have shows the effects.

See Figure 6, red line.

Follow up question in regards to WC math since we're on the subject, if you don't mind.

I don't have a mixing station (apartment), and am occasionally forced to do large WCs in emergency situations. Is there any sort of formula for calculating the tempature equilibrium between 2 bodies of water?

Let's say for example, my kid dumps something in my tank and I need to do an 80% WC. For me, that is filling up 4 separate buckets with 4 separate heaters and powerheads for hours, while my display tank sits almost empty. This is obviously impractical. However, if I could just dump the 4 buckets (in this case 4g each) and have some sort of formula that shows removing "X" rodi from the 4g and boiling it, will result in a tempature increase of "Y" when added back, then I could just boil a gallon or whatever on the stove and have an entire tank volume of water made up and temp'd in like 20 mins.

 

[rennjidk]

Follow up question in regards to WC math since we're on the subject, if you don't mind.

I don't have a mixing station (apartment), and am occasionally forced to do large WCs in emergency situations. Is there any sort of formula for calculating the tempature equilibrium between 2 bodies of water?

Let's say for example, my kid dumps something in my tank and I need to do an 80% WC. For me, that is filling up 4 separate buckets with 4 separate heaters and powerheads for hours, while my display tank sits almost empty. This is obviously impractical. However, if I could just dump the 4 buckets (in this case 4g each) and have some sort of formula that shows removing "X" rodi from the 4g and boiling it, will result in a tempature increase of "Y" when added back, then I could just boil a gallon or whatever on the stove and have an entire tank volume of water made up and temp'd in like 20 mins.

I actually found an answer on my own, just posting it in case it becomes convenient for someone else with a different system volume in an emergency. Here's the formula (NOT my math because I'm dumb, just copied and pasted):

"The temperature of a mixture of different temp waters can be expressed as ([volume of water] x [temp]) / volume of water. You have two volumes: the amount you’re intending to boil (x) and the amount you’re leaving in the tank (4-x)

(68(4-x)+212x)/4=76
272+144x=304
144x=32
x=.2222… gallons
28.4 fluid oz"

I thought It may be helpful coming up on power outage season with people heating water on gas stoves.