Is this some form of precipitate?

[jkobel]

I have some of this in my tank, in random spots here and there. I noticed it after using coral snow, appears to be detritus combined with coral snow (IMO). I also know it goes away within a week or so, I think my copepod population is consuming it.

Do you add pods regularly? What would you say your pod population is like?

 

[jkobel]

Double post

 

[TokenReefer]

Are you doing anything to remove it?

I vacuumed and scraped some out and it came back

Some? I'd be getting as much of that out as I could

 

[killer2001]

Do you add pods regularly? What would you say your pod population is like?

I don't add pods but I don't have anything to control my pod population, so they multiply with ease. Lets just say, if diatoms invade my glass, I'll have a cluster of copepods on the glass soon after.

 

[jkobel]

Are you doing anything to remove it?

Some? I'd be getting as much of that out as I could

Totally agree, i was over simplifying.

I blew off all the rocks a few times and brushed everything with a tooth brush and vacuumed and ultimately had to scoop a bunch of this junk off the sand. After a few rounds of all that over the course of a month and it keeps coming right back I am looking for a more sustainable method of getting rid of it.

 

[TokenReefer]

What's the time frame for how long it take to come back?

 

[92Miata]

Hey everyone,

I have been battling GHA for a few months and right at the beginning of that battle this purple stuff started showing up on my sand...


.....

Alk - 8.7
Ca - 437
Mg - 1390
Phos - 0.0
Nitrate - 0.0
Ph - 7.97
Temp - 78.1
Sal - 1.026

There is no end to the amount of weird biological stuff that can happen in a reef tank as a result of a tank being nitrogen or phosphorus limited and somebody continuing to try to aggressively remove those things from the water column because they believe that algae means high nutrients. Pest algae thrive in environments that are unbalanced, disturbed, or have very limited competition.

Everything you want to keep in a reef tank needs nitrogen and phosphorus (and generally gets carbon via photosynthesis and CO2 or bicarbonate) - and many of the things you don't want to keep have alternative methods of getting them (pulling nitrogen from the air, creating local low pH zones and dissolving the surface of rock, or literally just catching crud and having it break down in their fronds).


I'd guess Randy is correct here with the purple bacteria (or similar) - as they're able to photoautotrophically fix carbon (they can consume carbon without nitrogen and phosphorus - just need light) and you've created an environment where nitrogen and phosphorus are scarce, and carbon is most likely abundant. It's an environment tailored to their biology.

Think of pest algae like weeds in a garden bed in the spring. You don't combat them by stripping the environment of food/water - because that will kill your tomatoes faster than it kills the weeds, because the weeds are better at surviving in poor environments. You mechanically handicap the weeds by weeding, and tailor the environment to the tomatoes until they can grow tall enough, and get enough root mass that they can outcompete the weeds.


Siphon out as much of this stuff as you can, pull out as much of the hair algae as you can (get in there and scrub with a toothbrush if you need to), and then get some food into the tank(or nitrogen and phosphorus). If the hair algae grows long, do it again. You need to control this stuff mechanically while the biology of the tank gets back to normal. Once the purple stuff disappears - buy a rabbit fish or something to help with mechanical reduction of the hair algae.

And after a while, corals/coralline/etc will consume enough of some macro- or micronutrient fast enough that those tufts of algae that you're mechanically keeping short won't be able to get at it anymore, and they'll die.

 

[TokenReefer]

Think of pest algae like weeds in a garden bed in the spring. You don't combat them by stripping the environment of food/water - because that will kill your tomatoes faster than it kills the weeds, because the weeds are better at surviving in poor environments. You mechanically handicap the weeds by weeding, and tailor the environment to the tomatoes until they can grow tall enough, and get enough root mass that they can outcompete the weeds

An excellent example people can wrap their heads around. Well said!