How much nutrients does chaeto really export?

[jenjen]

Hi all. My question is regarding my 55gal. It's a sumpless/skimmerless 'natural' softie tank. I run PC lighting. I've got about a 5in fine sandbed, about 50lbs seeded lace rock. My stocklist is very light:

pair of clarkii's
YWG/pistol shrimp pair
tailspot blenny
2 cleaner shrimp
1 fire shrimp
emerald crab
staghorn hermit
orangelip conch
1 large feather duster
couple of misc snails and teeny hermits

I feed pellets most of the time because it's easier to monitor how much is going un-eaten, add a little frozen maybe weekly as a 'treat', and a bit of phyto daily for the staghorn. Nitrate has never been above 5.

NOW THE QUESTION: I have a very small bit of chaeto (smaller than a fist) in a breader container on the back of the tank. It isn't growing well. Before I spend time/money getting a better chaeto setup into this system I am wondering how much nutrient export I can actually expect to gain from the chaeto and whether it's worth my time to try and get it growing well.

Thanks

 

[Randy Holmes-Farley]

A very small amount, or any that isn't growing well is not very useful.

I detial the amounts here:

Phosphate and the Reef Aquarium
http://reefkeeping.com/issues/2006-09/rhf/index.php


from it:

Phosphate Export by Organisms: Macroalgae



--------------------------------------------------------------------------------

Growing and harvesting macroalgae can be a very effective way to reduce phosphate levels (along with other nutrients) in reef aquaria. In my reef system, where I have large, lit refugia to grow the macroalgae Caulerpa racemosa and Chaetomorpha sp., these algae are clearly the largest phosphate export mechanisms. Aquaria with large amounts of thriving macroalgae can avoid microalgae problems or excessive phosphate levels that might inhibit coral calcification. Whether the reduction in phosphate is the cause of the microalgae reduction is not obvious; other nutrients can also become limiting. But to reef aquarists with a severe microalgae problem, the exact mechanism may make no difference. If rapidly growing macroalgae absorb enough phosphorus to keep the orthophosphate concentrations in the water column acceptably low, and at the same time keep microalgae under control, most reefkeepers will be satisfied.

For those interested in knowing how much phosphorus is being exported by macroalgae, this free PDF article in the journal Marine Biology has some important information. It gives the phosphorus and nitrogen content for nine different species of macroalgae, including many that reefkeepers typically maintain. For example, Caulerpa racemosa collected off Hawaii contains about 0.08 % phosphorus by dry weight and 5.6% nitrogen. Harvesting 10 grams (dry weight) of this macroalgae from an aquarium would be the equivalent of removing 24 mg of phosphate from the water column. That amount is the equivalent of reducing the phosphate concentration from 0.2 ppm to 0.1 ppm in a 67-gallon aquarium. All of the other species tested gave similar results (plus or minus a factor of two). Interestingly, using the same paper's nitrogen data, this would also be equivalent to reducing the nitrate content by 2.5 grams, or 10 ppm in that same 67-gallon aquarium.

 

[Jared J]

Also remember, the nutrients aren't really exported until the chaeto is trimmed and disposed of.

 

[JeF4y]

Also remember, the nutrients aren't really exported until the chaeto is trimmed and disposed of.

(Please correct me if I'm wrong, but I always hear people make the above statement and it doesn't really make that much sense to me because...)

However, the nutrients are no longer in the water column, so it's not harming the tank right? As long as the Macro is growing and you have room for it to grow, why trim? The nutrients are in use in the Macro and not by the rest of the aquarium so why bother?

 

[Jared J]

You will eventually need to trim the chaeto. Theres always the possibility that something will cause the chaeto to die off or turn to mush. If it does that it will release those nutrients back into the water.

 

[tmgrash]

A very small amount, or any that isn't growing well is not very useful.

I detial the amounts here:

Phosphate and the Reef Aquarium
http://reefkeeping.com/issues/2006-09/rhf/index.php


from it:

Phosphate Export by Organisms: Macroalgae



--------------------------------------------------------------------------------

Growing and harvesting macroalgae can be a very effective way to reduce phosphate levels (along with other nutrients) in reef aquaria. In my reef system, where I have large, lit refugia to grow the macroalgae Caulerpa racemosa and Chaetomorpha sp., these algae are clearly the largest phosphate export mechanisms. Aquaria with large amounts of thriving macroalgae can avoid microalgae problems or excessive phosphate levels that might inhibit coral calcification. Whether the reduction in phosphate is the cause of the microalgae reduction is not obvious; other nutrients can also become limiting. But to reef aquarists with a severe microalgae problem, the exact mechanism may make no difference. If rapidly growing macroalgae absorb enough phosphorus to keep the orthophosphate concentrations in the water column acceptably low, and at the same time keep microalgae under control, most reefkeepers will be satisfied.

For those interested in knowing how much phosphorus is being exported by macroalgae, this free PDF article in the journal Marine Biology has some important information. It gives the phosphorus and nitrogen content for nine different species of macroalgae, including many that reefkeepers typically maintain. For example, Caulerpa racemosa collected off Hawaii contains about 0.08 % phosphorus by dry weight and 5.6% nitrogen. Harvesting 10 grams (dry weight) of this macroalgae from an aquarium would be the equivalent of removing 24 mg of phosphate from the water column. That amount is the equivalent of reducing the phosphate concentration from 0.2 ppm to 0.1 ppm in a 67-gallon aquarium. All of the other species tested gave similar results (plus or minus a factor of two). Interestingly, using the same paper's nitrogen data, this would also be equivalent to reducing the nitrate content by 2.5 grams, or 10 ppm in that same 67-gallon aquarium.

Good info, thanks

 

[slief]

Will Chaeto growth be inhibited by the use of a reactor with GFO? I am adding a fuge to my system and already have a reactor with GFO running.

 

[Randy Holmes-Farley]

Yes, the growth of macroalgae can be slowed or stopped by other methods that drive phosphate too low for it to grow.

My macroalgae growth has slowed considerably since initiating organic carbon dosing.

 

[hihikeke]

I don have any algae going crazy in the tank, but it never hurts to have one, right?

 

[DThompson]

Also remember, the nutrients aren't really exported until the chaeto is trimmed and disposed of.

This is not making sense to me. So are you saying that the Chaeto merely stores the phosphates? It does not consume them? Also, if the export is not complete until we trim and remove the Chaeto, does this mean we are giving "Phosphate full" Chaeto to our fellow hobbyist when we give it away to others?

Hope you can see why I am having a hard time getting my head around this. It would seem logical to me that the Chaeto is consuming the nutrients rather than just storing them.

 

[Randy Holmes-Farley]

I think you have a good understanding. The idea is just that if the macroalgae dies (or is eaten, etc.), it might release the nutrients again, but as long as it is alive, the nutrients are as good as exported.

 

[luther1200]

Will Chaeto growth be inhibited by the use of a reactor with GFO? I am adding a fuge to my system and already have a reactor with GFO running.

Yes, I noticed a slow down after I started using GFO. But now after about 12-14 months of carbon dosing I don't have any Macro at all anymore. It kept wilting away until I finally just removed the rest. But it kept growing good for a while even after the GFO and carbon dosing.

 

[100%hydrophylic]

This is not making sense to me. So are you saying that the Chaeto merely stores the phosphates? It does not consume them? Also, if the export is not complete until we trim and remove the Chaeto, does this mean we are giving "Phosphate full" Chaeto to our fellow hobbyist when we give it away to others?

Hope you can see why I am having a hard time getting my head around this. It would seem logical to me that the Chaeto is consuming the nutrients rather than just storing them.

in this situation "you are what you eat" applies pretty well. chaeto does not poop. and by law of conservation of mass matter can not be created nor destroyed, so you can break things down but they will not be destroyed. soooo chaeto doesnt make nitrate/phosphate go poof. storing may not be the best way to put it though. you know the nitrogen cycle i assume. something dies, creates ammonia, turns into nitrite then nitrate. welll the chaeto absorbs the nitrate and other nutrients but if it dies the decaying matter will create ammonia then nitrite then nitrate...... youl probably just see the nitrate because the others are broken down so quickly

 

[eidillitih]

jenjen, I hope yu don't mind me jumping in with my own related questioin. I have about two gratefruit size cheato in my fuge. I'm running phospate remover and dosing vodka. I don't have much bio-load (just one fish). Now I begin to see my cheato fading white (dieing). Would it be better just to take the cheato out. Cause I'm guessing the low phospates in the water is killing it. I think it's making my water slightly cloudy.

 

[Octoshark]

Now I begin to see my cheato fading white (dieing). Would it be better just to take the cheato out. Cause I'm guessing the low phospates in the water is killing it. I think it's making my water slightly cloudy.

That may be your best bet, or reducing the total amount of chaeto.

 

[Randy Holmes-Farley]

Caulerpa racemosa that some of us use seems better able to compete (even out competing Chaeto), so it may last when Chaetomorpha cannot.

 

[DThompson]

in this situation "you are what you eat" applies pretty well. chaeto does not poop. and by law of conservation of mass matter can not be created nor destroyed, so you can break things down but they will not be destroyed. soooo chaeto doesnt make nitrate/phosphate go poof. storing may not be the best way to put it though. you know the nitrogen cycle i assume. something dies, creates ammonia, turns into nitrite then nitrate. welll the chaeto absorbs the nitrate and other nutrients but if it dies the decaying matter will create ammonia then nitrite then nitrate...... youl probably just see the nitrate because the others are broken down so quickly

Is there a paper on this I could read? Some sort of study? Because this makes no sense. I have had quite a bit of Biology and this is hard for me to grasp. The plant is taking in something and then unable to expel through gas exchange or another method? (Obv gas exchange in this case)

So what happens when it reaches max capacity? If it is not exchanging the material, rather storing it, then I would assume that it is not using it as energy for growth. Am I wrong?

Thanks

 

[Randy Holmes-Farley]

I think you're over-analyzing the situation. If it dies it releases nutrients. If it does not, it does not. End of story. There is no concern unless it dies.

If it just stops growing rapidly, it stops taking up nutrients rapidly. But they are not released unless it dies.

 

[luther1200]

Is there a paper on this I could read? Some sort of study? Because this makes no sense. I have had quite a bit of Biology and this is hard for me to grasp. The plant is taking in something and then unable to expel through gas exchange or another method? (Obv gas exchange in this case)

So what happens when it reaches max capacity? If it is not exchanging the material, rather storing it, then I would assume that it is not using it as energy for growth. Am I wrong?

Thanks

Its just like anything else. All your fish food was live and growing at 1 point. Either plants or animals, and they take up nutrients to live and grow. If any living thing decays in water it will release those nutrients back into the water, on land it would be the soil.

 

[arrowheadpuffer]

So what happens when it reaches max capacity?

It grows! There is no max capacity, until it has completely overgrown the tank. Just like how people fertilize plants with fertilizer containing phosphates, the plant takes in the phosphate (and other nutrients), grows, and then needs more to grow more.