Chaeto & GHA - too much ChaetoGro+Iron?

[Kelliwilliams817]

Hey guys!

So I've been trying to setup a small quarantined chaeto farm to service three of my LFS and get a little coral money!

I've got the flow down with everything nicely tumbling, Kessil fuge lights dialed in, etc. Chaeto has been growing but so has the GHA. So I went back to the basics and drastically lowered my phosphate dosing.

Over the weekend, GHA completely exploded. Water is testing 50ppm nitrate and 0 phosphate. However, I have been dosing about 70ml of ChaetoGro and 30ml of Ferrion every day (100 gallon setup with nothing but chaeto).

Two questions:

Can low levels of phosphate but extremely high levels of trace/iron lead to a GHA explosion?

If I turn off the lights and put the chaeto/GHA mass in an aerated bucket with nothing but fresh saltwater (0 nitrate 0 phos 0 ChaetoGro 0 iron) and change the water every day for a week, will the GHA die but the chaeto survive?

 

[Mr. Mojo Rising]

I'm not sure how accurate nutrient testing would be in a macro algae tank that has hair algae, both will consume the nutrients which would skew the test results. For that reason I don't test on my macro algae tank, I just judge based on the color and growth of the macro algae and lack of other algae's.

 

[Subsea]

Hey guys!

So I've been trying to setup a small quarantined chaeto farm to service three of my LFS and get a little coral money!

I've got the flow down with everything nicely tumbling, Kessil fuge lights dialed in, etc. Chaeto has been growing but so has the GHA. So I went back to the basics and drastically lowered my phosphate dosing.

Over the weekend, GHA completely exploded. Water is testing 50ppm nitrate and 0 phosphate. However, I have been dosing about 70ml of ChaetoGro and 30ml of Ferrion every day (100 gallon setup with nothing but chaeto).

Two questions:

Can low levels of phosphate but extremely high levels of trace/iron lead to a GHA explosion?

If I turn off the lights and put the chaeto/GHA mass in an aerated bucket with nothing but fresh saltwater (0 nitrate 0 phos 0 ChaetoGro 0 iron) and change the water every day for a week, will the GHA die but the chaeto survive?

Short answer: no to both questions. Also, GHA is a catch all name for many variety of seaweed.

Normal ratio of N:P in biomass of seaweed is 30:1.

Seaweed growth is not controlled by the most abundant nutrient, however, it will be limited by the least abundant.

 

[Randy Holmes-Farley Verified Community Expert]

Seaweed growth is not controlled by the most abundant nutrient, however, it will be limited by the least abundant.

So many people misunderstand that, which is why I posted this article yesterday to help folks:

https://www.reef2reef.com/ams/forget-redfield-liebig-is-the-man.1176/

 

[vlangel]

So many people misunderstand that, which is why I posted this article yesterday to help folks:

https://www.reef2reef.com/ams/forget-redfield-liebig-is-the-man.1176/

Randy, I appreciated this article. It helped me understand better why my high nutrient system has worked pretty well. I was operating that way because my past reef experience taught me that it could work. I remember when I was first getting on reef forums around 2012 and testing my nitrates and phosphates for the first time (mind you I had been keeping a reef for over a decade) and being horrified at how high both my nitrates and phosphates were. However, I did not have a nuisance algae issue and I was fairly successful with soft coral and some LPS. At that time I was reading that one should strive for ultra low nutrient systems and especially phosphates. In my uneducated mind I decided that I just wasn't going to try more difficult coral because I wasn't going to try and keep a reef that way. I guess that is why I never had dinos and happened to stumble into a successful way to keep a simple mixed reef. With adding cheatogro, and water changes, apparently most everything I am keeping is not limited. Its been my belief that most macroalgae outcompete most nuisance algae or again maybe I have just stumble on something in practice that is working that I don't really understand the whys or hows? All I know for sure is I have never struggled with bad algae. To keep more SPS, I probably need to address the lack of calcium and alkalinity in my tank, which I have been experimenting with. I use regular IO which I know is very low in both of those, which is why my tank has almost no coraline algae. That's why I have been trying AFR and also Sea Lab #28. I realize that its kind of risky dosing blind but I am not a precise reef keeper, I am more of an observant reef keeper. I don't have coraline algae so I figured that I am not overdosing, that and the corals seem happy. Anyway back to your article, thank you for sharing.

 

[Randy Holmes-Farley Verified Community Expert]

I guess that is why I never had dinos and happened to stumble into a successful way to keep a simple mixed reef. With adding cheatogro, and water changes, apparently most everything I am keeping is not limited. Its been my belief that most macroalgae outcompete most nuisance algae or again maybe I have just stumble on something in practice that is working that I don't really understand the whys or hows?

A sufficiently large clean up crew can keep algae under control regardless of levels in the water. Is that a possible explanation?

 

[vlangel]

A sufficiently large clean up crew can keep algae under control regardless of levels in the water. Is that a possible explanation?

CUC is definitely helping right now since I have nassarius and astrea snails, a few small hermits, a cucumber and a fighting conch. This is the biggest CUC I have ever had so there is no doubt that they are controlling some nuisance algae.

 

[SantaMonica Verified Sponsor]

Might have been chaeto's lesser ability to photosynthesize than GHA. As you stopped dosing and levels got lower, only the GHA could grow. I have a new patent that uses this to an advantage.