Water changes vs Evaporation (1 Viewer)

[Copingsaw]

I'm curious to find out what people's opinions are on the role evaporation plays in acheiving water changes.

I have a couple of small tanks and I have religiously done 20% water changes every other week. I don't have a skimmer on my 12-gallon nanocube so I have been especially careful to complete water changes on that tank. During these hot summer months I am running fans to cool the water temp and the amount of evaporation has increased significantly. I am topping off my 20-gallon with a good 1/2 gallon of water daily to make up for evaporation. I figure that adds up to about 4 gallons or 20% of the tank volume weekly.

Does this qualify as a water change or is there a good reason to exchange mixed water? The only thing I can think of is that fresh salt may contain certain beneficial elements or something and, therefore, it would be a good idea to do water changes in addition to just making up for evaporation.

 

[tedu]

You've answered part of your own question. Water changes replace depleted trace elements.

The other part is that water changes remove waste, simply replacing evaporated water doesn't.

 

[MarkieB]

Evaporation does not replace water changes!

The bad stuff, detrious, does not evacuate with evaporation!
As well as the trace minerals you guys mentioned.

If you operated under that theory for a year, you would most likely suffer a tank crash! Too bad, I wish it did work!

 

[Guest]

What Markie said. The reason for water changes is to renormalize the water composition: remove bad dissolved solids, replenish good dissolved solids. All you're doing through evaporation is exchanging H2O molecules 1 for 1.

Reminds me of the guy who's car burned oil. he stopped changing the oil because he was adding 4 quarts a month

 

[Copingsaw]

Thank you for answering my question. I knew in the back of my mind that there had to be a better reason that I was coming up with.