A few newbie questions on Macroalgae and corals

[Shawn O]

OK, I've seen these things talked about, but not in depth on a couple of matters so here goes...

First: I hear people saying they use macroalgae to remove phosphates from the tank but then feed those same macros to their tangs. Doesn't this just put the phosphates back into the tank since the tangs eat the phosphate laden macroalgae and then poo it back out? Do the fish absorb the phosphates into their tissue without it becoming an issue of being toxic after a long time?

Second: I hear of corals engaging in chemical warfare with one another. I can understand this between different species but am unsure of it with the same or related species. As an example, if I had two different colored Montipora digitata, would they fight it out if they grew into each other? Also, if were to frag a 6" Montipora digitata into several frags and placed them close to each other would it be an issue when they get larger and grow closer to each other? Or, if they were say, a branching acropora and a bird's nest?

Thanks in advance for any info you can provide.

 

[Puffyluv]

Really interested to hear someone take a stab at the first question...I will take the second!

No, two of the exact same species of coral will usually not sting each other. In fact, many times you can get away with touching corals that have the same "first name"...such as montipora capricornis and montipora digitata...always fun gluing combo frags of these two!

Notice I said usually? Well, there is always that one instance that will prove you wrong when you make a blanket statement like that...and besides, most of the time when we state the scientific name in this hobby we are just guessing. Nobody is sitting there with a microscope and some bone cutters in a lab coat proving this...not PROOF, you see, just a guess. Soooo, though I will say sure, go ahead and try it...I will still say watch carefully to be sure! Similar corals may sting each other, just not as bad as say, an acan vs. an acro.

Ok, let's hear that first question, (seems worth knowing, and I have never heard anyone ask before!) I want to know what the chemistry experts have to say about that!

 

[Shawn O]

Thanks for the info Puffyluv

 

[Puffyluv]

No prob! My guess on the first question is yes, much of the phos is pooped right out, while some is absorbed by their bodies. I am really not a chem nut, tho, should wait for someone not guessing on that one. Anybody could GUESS, lol...

 

[Dan_P]

OK, I've seen these things talked about, but not in depth on a couple of matters so here goes...

First: I hear people saying they use macroalgae to remove phosphates from the tank but then feed those same macros to their tangs. Doesn't this just put the phosphates back into the tank since the tangs eat the phosphate laden macroalgae and then poo it back out? Do the fish absorb the phosphates into their tissue without it becoming an issue of being toxic after a long time?.

Most of the phosphorus that fish eat is excreted. So, you are correct. The goal is to harvest and get rid of more macro algae than you feed to the fish, though fish health comes first on the list of priorities, before phosphate level.

 

[jayball]

Most of the phosphorus that fish eat is excreted. So, you are correct. The goal is to harvest and get rid of more macro algae than you feed to the fish, though fish health comes first on the list of priorities, before phosphate level.

You have to feed the fish anyway, may as well do it with recycled nutrients. I would imagine feeding with live Macro would be cleaner than nori anyway, It is not rotting as it sits in the tank waiting to be finished.

 

[Sk8r]

In short, yes, it does cycle phosphate through the tank, and feeding phytoplankton I suspect even more so.

This is why getting something to eat the algae is not as good an answer as a GFO reactor, which sucks up and binds the phosphate so it can't recirculate.

Some amino acids bind up phosphate and those are, perhaps, taken out by the skimmer. http://homepage.smc.edu/wissmann_paul/anatomy2textbook/AAcidsProteins.html

But in general, the reason HAIR algae is so bad is that your first rock---especially rock that was never in a tank before comes in loaded with phosphate. Hair algae attaches to such rock and just loves the phosphate that comes leaking out ---and out---and out. It will grow just so long as that rock leaks phosphate. WHich is why it can take GFO a few months to get rid of your hair algae.

You will notice that GFO generally doesn't impact your macroalgaes. They are apparentlly not the phosphate sinks that hair algae is, for whatever reason. You can kill off all your hair algae with GFO, but your cheato in your fuge will remain dark green, and thrive. So the hair algae has got to need far more than satisfies the cheato.

Hope that makes sense to you.

You can note the rise of film algae as either your rock finds some deep reserve of phosphate---or you overfeed in the 'green' category---but to answer your question---yes, but.

 

[Shawn O]

Good to know, thanks much.