sargassum question

[Stacey Wood]

It seems that I have inherited a 29 gallon reef tank (with 10 gallon sump) from my son. He started it at age 15 and now at age 17 his interests have changed. The tank is in fairly good condition with the exception that it is overrun with sargassum. I pulled as much of it off the rock as possible (filled a 5 gallon bucket about half full!!)but like any plant, it appears to have roots that you can't extract from the rock.

I know this is probably not the correct forum for this but:

If I keep up with frequent water changes, etc, etc. will the "roots "eventually die off if I keep harvesting this stuff as soon as I see that it is starting to grow?

(I've thought about just replacing the rock a piece at a time but I'm guessing that it probably would be infiltrated with "spores" that are already in the tank and I would be back where I started)

 

[graveyardworm]

Not sure how you got the id on the algae, but I believe sargassum generally floats and grows in mats. Its more likely what you have is some sort of hair algae. It is unlikely the roots will just die off, If conditions are not right for its growth, they will most likely become dormant and wait for conditions to be right again. Proper filtration with a good skimmer, regular water changes, a clean up crew with appropriate herbivores, and competition for nutrients with macro algae are all important in keeping nuisance algae at bay. Any chance you post some pictures.

 

[Stacey Wood]

here is a photo

 

[tekknoschtev]

Nope, thats sargassum. Sargassum generally is a floating plant but in my experience, it will develop holdfasts and attach to rocks - thats how we got it in.

Truth be told, we just pulled it off of a rock and called it a day. The bits on the rock apparently died off and did not start to produce more plants. Now we have it floating and weighted down in the fuge of our 150 - growing well. Definately adds a little something to the fuge dominated by chaeto and frags. We've been working to diversify the plantlife in the fuge.

 

[Stacey Wood]

The holdfasts currently seem to regrow. is there anyway to keep this from happening?

 

[mr_fosi]

Turn the rocks so the holdfasts are away from the light? That is more of a band-aid than anything, but it is easier than the sure-fire alternative.

The only way that I have been able to defeat invasive macroalgaes (like caulerpas) was to "cook" the rock for a couple weeks.

If you just want to kill the macroalgaes, you don't have to do it for months. Just 3-4 weeks in a 10g tank masked with junkmail worked for me.

EDIT: Check your PM box.

 

[slow_leak]

Might want a small tang, but why not just harvest it. It looks nice if arranged right.

 

[dalbrecht]

Here's a thought, but has anyone tried controlling macro with kalk paste?

 

[stevebla]

don't worry

don't worry

I have a lots of sargasum in the display tank i just thin it out now and then, I think it looks nice and is easy to thin.

 

[piercho]

Stacey, its certainly a brown algae, looks like Sargassum to me, I'd guess Sargassum hystix. Not distinct in your picture but characteristic are clusters of little "balls" around the stem - these are what gives Sargassum its boyancy. Sargassum, when attached, grows upwards from a holdfast. In the wild, strands of Sargassum that break loose will float to the surface and cluster in rafts, continuing to grow and making their own micro-habitat at the surface of the open ocean.

Resistant to snails, most fish, and - IME - urchins, including Diadema. Some tangs of genus Naso are supposed to eat brown algaes but these are very large tangs. On the positive side, a controllable and easily harvested macroalgae. Growth of Sargassum will slow and eventually stop, IME, if the tank water becomes lean enough. My advise is to let it sponge up nutrients in your tank and then harvest excess Sargassum by hand rather than try to eradicate it.

If you just want to kill it, the rock can be placed in a light-deprived tub and "cycled" for 6 or more weeks. Search for threads on "rock cooking".

 

[piercho]

I've thought about just replacing the rock a piece at a time but I'm guessing that it probably would be infiltrated with "spores" that are already in the tank and I would be back where I started

True for many of the worst algae (Valonia, Asparagopsis, Bryopsis) but IME not Sargassum. Sargassum does not even spread readily from fragments or spread quickly by growth of its holdfast across the rock. This is why I consider it a "good" algae for a reef display, if the tank has enough nutrients for it to grow.