DiScussion of the Week ~The use of algaes~

[mojoreef]

Many people in the hobby these days use algae in many different ways. Nutrient uptake in refugium, turf algae in scrubbers and so on and so on. But in reality are they even worth it? They are leach the nutrients back into the tank even on a good day, we run the risk of haveing them going sexual and dumping thier whole nutrient load back in. We cant feed these algaes back to our fish as they are full of nutrients and will eventually cause the fish to succumb to it.
So why do we do it? Is it another biodiversity thing? Do we just like the pretty green colors? Do we have a deep seeded need to harvest the stuff.

What say you all pro's cons?????

[galleon]

Well basically you're stuck with it either way. Algae holds the record for biomass to reef surface area ratio on all reefs. It is vitally important for the food web on reefs for grazing and biogeochemical reasons. I don't believe it should be the primary means for removal of nutrients by any means. Just take a look at all the problems Adey had (Sprung and Delbeek, The Reef Aquarium, V.1). Keep overrunning species that you have no grazers for out (Caulerpa sp., etc.). Others will keep themselves under control via grazers and self limitation from nutrient, space and light availability. Get rid of detritus and have a ginormous protein skimmer and UV. NO dsb.

I hate algae. That is all.

[Reedman]

I'm curious, are there any attractive, slower growing algaes that could be used in a refugium to process nutrients and provide shelter for critters. I would like to avoid the calurpa route because it just grows way too fast. I understand that this provides the best export, but I woul like to have the refugium as a display above my main tank.

Thanks in advance.
-Reed

[wasabi]

i have had feather in my refugium, and large 2 foot x 2 foot masses of halimeda in my main tanks. the feather has never gone sexual but i pull half a five gallon bucket every three weeks. all in all the halimeda seems to be a fast growing excellent nutrient export. iv'e been harvesting both algeas for over two years. this is an sps tank i've heard the leaching tale but cannot cofirm that it is true, because i've had great results so far.

[wildthings44]

I have tons of algae in my tank... but then I don't have much to eat it. Most of it is calerpa types that are harvested monthly, but I have halimeda and a couple of other wierdos in there (I am unsure of the names, but I know one is called "finger algae", as to the others....?) I like it, I wish it would grow so well in freshwater tanks (don't get me going on my stupid freshwater tank... just about ready to tear it down and do salt, which seems so much easier these days...) I would love to get some of the red stuff, just to see how it does. But then I don't have a sps tank and I am pretty loose on how my tank looks. I like to have the "wineglass" calerpa growing around some of my softies, it fills in the gaps and looks like a lawn of pretty green (since I can't have a real lawn in this desert country...)
It also provides places for fish, as well as the "coodies", to hide in the tank.
I don't know, I guess I am just backwards...

[dark horge]

The number of 'problem' algae are actually quite smal, compared to the unoticed majority that make coral reefs (both wild and captive) even remotely possible.

Using 'farmed' algae for nutrient export in aquaria is an involved topic, and I'll post on that in a bit (takes time to hammer out a coherent outburst).

[CAT]

I have a 28 gal. bowfront that I won't be upgrading until I stop moving every year. This little tank did well for a while, then the nitrates/phosphates started to climb. I added a fuge to it, filled it with macros and a few rocks and the nitrates disappeared. The different macros seem to come and go, almost like they're taking turns, but the water quality remains excellent. I have a 50/50 PC for lighting on the fuge so I don't get outrageous growth. Works for me

[mojoreef]

In order to make a meaningful comparison, we need some standardized measure of growth, however, because a "stalk" of one alga and another may be quite different. The most common measure is "specific growth rate" in which the growth is measured in mg per gram of algal body weight per day, or percentage increase. So, to compare the specific growth rates of some of the more common species that I can find data for, the maximum growth rates appear to be something like this:

Halimeda: ~2% / day (10-20 mg/g/d)
Dictyota: ~ 10% (50-100 mg/g/d)
Padina: ~ 10% (75-100 mg/g/d)
Caulerpa: ~ 10% (50-100 mg/g/d)
Thalassia: ~1.5% (10-15 mg/g/d)
Palmaria: ~15% (doubled in 1 week)
Enteromorpha: 20% (7 fold increase in 1 month)
Gracilaria: 6-10% / day

However, if you want to maximize the nutrient export, the clear winner in field experiments is the cyanobacteria Lyngbya, which grows at a rate of roughly 5 times that of any of the common macroalgae in the trade, and adds an average of about 35% (300-400 mg/g/d) of it's weight per day! But it would be a pain to remove and looks like hell....

So, obviously there is a bit of a trade-off that we have to take into account when we talk about nutrient export. We want something that grows fairly quickly to remove nutrients, but also you want something that is easily controlled, harvested, and doesn't make your tank look like a cesspool. The other consideration is that most of the common algae on the reef (e.g., Dictyota, Padina, Caulerpa) are often highly chemically defended (otherwise they are eaten by herbivorous fishes), and most people seemt to be trying to avoid such species in their tanks. So you have to balance the specific growth rate against the suite of secondary chemicals which these species release and the ability to harvest them for nutrient export. So, taking all of this into account (growth, ease of removal, chemical defenses, probability of overgrowth, appearance, etc.), my favorite choices for macroalgae in my own tanks is typically Halimeda or Ochtodes if included in the main display tank, and Enteromorpha, or Graciliaria, if included in a refugium or a sump....

MIKE

[Jimbo]

I have several types of caulerpa in my refugium and have recently cultivated some halimeda in the main tank to slow the growth of the feather caulerpa. Halimeda's biomass is much greater than caulerpa (Feather), so even though it appears to grow slow it's probally on par with other macro algeas from my observation.

The halimeda is much easier to harvest and it does not put down tracers all over the rocks. It also does not ooz out fluid like caulerpa does when harvested. Halimeda seems to be sensitive to trace elements, since I've done several water changes have seen a markatable increase in growth.

[mojoreef]

Halimeda seems to be sensitive to trace elements, since I've done several water changes have seen a markatable increase in growth.

yep it does like calcium

mike

[Big Dave]

Originally posted by Jimbo
The halimeda is much easier to harvest and it does not put down tracers all over the rocks. Halimeda seems to be sensitive to trace elements, since I've done several water changes have seen a markatable increase in growth.

Jimbo-
I've noticed almost the exact opposite. I pulled a small section out of my sand and it pulled up a golfball sized root mass. Also, I have done one water change in the last 4 months and it has grown fast the entire time. Although, I do add calcium every week to my tank of softies and LPS!

Big Dave

[CAT]

Originally posted by Jimbo

The halimeda is much easier to harvest and it does not put down tracers all over the rocks.

I've had no luck with halimeda Had some in my old tank but the hippo and sally ate it all. I also bought a bunch that must not have been cut right because it disintegrated in the tank.

How do you harvest this stuff? Does it need to have some roots attached?

[Flatlander]

As one of the few that seem to run a large turf scrubber, guess I had better add my 2 cents worth.

Are turf scrubbers the answer. I dont know anymore. I would ask why have they not seen more use. The large units, like mine, cost no more than a large beckett and pump.

The turf algae does not go sexual, like my refugium/algae removal system did. I sometimes wonder how much it helps overall though. It seems not to prevent nor help cyno growths. One must wonder how much ammonia, nitrate, nitrite , phosphate, etc. its removing.

I dont use an ro anymore, but would not its use on my well water and the several hundred pounds of rock I have, do some of the same.

I have no use for refugiums myself. I never found they provided anymore food than my pod piles and all the rock I have in the show tank. And as mentioned my attempt at a large tub/sandbed/calerpa nutrient removal system was a failure. Seemed like a major pain to me, then one day my tank was green pea soup. Many aquarists I talk to, now have the same conclusion.

I do, on the other hand, like some in the main tank. I agree with others about hamilda, also my favorite. I have also taught some, a cheaper way to do a fish/modified reef tank, by harvesting lots of calerpa in the show tank. I still think Montys tank on Aqualink, full of razor calerpa, is a very nice tank and an excellent alternative for some.

For myself, I have to go with Chris. I have removed any sandbed, {added some fine, easily cleanable crushed coral piles in the back for my leopard I could not bare to part with, }. Have lots of live rock, but well stacked, with good flow. Trying to keep most detritous in suspension, to be picked up by the beckett skimmer.

[dark horge]

ATS' are a boon in high-import setups, just like DSB's are. If your import of food is moderate or light, and you already have various waste procesing agencies on board, you are unlikely to notice a significant improvement re nitrogenous waste concentrations.

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Regarding Halimeda
They are a pretty good algae for nutrient management ---you just have to understand how to harvest them.

The chloroplasts migrate periodically to the growth tips:

The plant turns white at night, right? That's because the chloroplasts hunker down under all that calcium armor. More to the point, the chloroplasts migrate towards the fresh growth-tip/disc, to accelerate, well, growth. If you trim off this growth-tip when most of the chloroplasts are there, you may eliminate the bulk of the specimen's chloroplasts, and effectively kill it.

For larger species, I like to husband several individual specimens. I harvest WHOLE specimens at a time. Halimeda are very cheap anyway. I plant them, and then after five months uproot and ditch. Otherwise, trim only when what will remain is green. If the part to be trimmed off is the only green, then don't.


H. opuntia is a rabid attacher, and branches like nobody's business. Tearing out whole strands works for me, making sure to leave as much green stuff alone. I sometimes trim off the BOTTOM, since the specimen is also attached further up on its body.


Honestly, I don't really trim/harvest for export.
The primary reason is that the stuff just gets too big.

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