brown algae killed by water change

[punchy]

i just noticed that the top 3" of algae is completely gone from my tank, almost as if perfectly scraped clean by a magnetic algae scraper.

i can think of only a water change which i did a few days ago, which emptied the tank of ~3" of water, as the cause.

the tank is 2 months old and the algae coverage is light and brown in color, so i'm guessing i'm dealing with brown diatoms - do they die easily, ie out of water for ~20 mins?

this isn't a problem as much as a curiosity, and i don't remember this happening before... granted i may not have been that observant before

and, hello rc! :wave:

 

[dkeller_nc]

Welcome to reef central!

Normally, an algae layer (or diatoms, or cyanobacteria) won't die from being out of the water for just a few minutes because the layer won't dry out that fast.

However, if you did perform a water change that lasted an hour or more because you cleaning rock or equipment in the tank, then yes, you'd expect any creatures or algae out of the water that long to die.

 

[CStrickland]

I bet they just got unstuck from the surface. Diatoms are pretty powdery, you can use a turkey baster to puff them off the rocks. Seems like as the water went up and down during the change the same thing would happen on your glass. Maybe you were a little splashier this time or maybe they are starting to finish their peak in your cycle so they aren't coming back as fast as they did before