When to start dosing for macro?

[KonradTO]

Hi all,
I have a 32g tank. The plan is to have a mixed reef tank with mostly LPS, but for now I have only some macro (Caulerpa, halymeda and apparently some Galaxaura) lots of fanworms and pods and an hermit.
Since the macro, and especially Caulerpa, are growing really fast (I have to trim weekly) , I am a bit worried that I am going to deplete all the nutrients for the slower plants and corals I am gonna introduce soon. Are micronutrients included in the salts for the water change or I should start dosing at some point? I would like to have the macros simply balancing the nutrient in the tank without relying on NPK supplement, but for micro its a complete different story I guess..

 

[KonradTO]

I forgot to mention, I do 10% weekly WC and I ghost feed the tank to keep the nutrients higher for now that I am under stocked

 

[Dan_P]

Hi all,
I have a 32g tank. The plan is to have a mixed reef tank with mostly LPS, but for now I have only some macro (Caulerpa, halymeda and apparently some Galaxaura) lots of fanworms and pods and an hermit.
Since the macro, and especially Caulerpa, are growing really fast (I have to trim weekly) , I am a bit worried that I am going to deplete all the nutrients for the slower plants and corals I am gonna introduce soon. Are micronutrients included in the salts for the water change or I should start dosing at some point? I would like to have the macros simply balancing the nutrient in the tank without relying on NPK supplement, but for micro its a complete different story I guess..

Trace element depletion by macro algae seems like a possibilty.

I grow Ulva for nitrate control. I noticed that the Ulva initially grew very well but started to weaken and developed patches of cyanobacteria. Nitrate and phosphate were adequate. I tried Chaeto Gro and that seemed to cause the Ulva to start growing again (coralline too) and it continues to do well. I use the recommended daily once per week because higher doses sickened my Mexican turbo snails (they stopped eating and moving around).

 

[KonradTO]

Trace element depletion by macro algae seems like a possibilty.

I grow Ulva for nitrate control. I noticed that the Ulva initially grew very well but started to weaken and developed patches of cyanobacteria. Nitrate and phosphate were adequate. I tried Chaeto Gro and that seemed to cause the Ulva to start growing again (coralline too) and it continues to do well. I use the recommended daily once per week because higher doses sickened my Mexican turbo snails (they stopped eating and moving around).

OK I see. Today I checked for Ca and it seems to be OK (450 ppm). NO3 are at zero so macro rather than micro might be the problem.. Is chaeto grow micro or macro+micro fertilizer? I could dose some npk in case..

 

[Dan_P]

OK I see. Today I checked for Ca and it seems to be OK (450 ppm). NO3 are at zero so macro rather than micro might be the problem.. Is chaeto grow micro or macro+micro fertilizer? I could dose some npk in case..

I don’t have the bottle in front of me. I think it is only trace elements

 

[Subsea]

OK I see. Today I checked for Ca and it seems to be OK (450 ppm). NO3 are at zero so macro rather than micro might be the problem.. Is chaeto grow micro or macro+micro fertilizer? I could dose some npk in case..

ChaetoGrow has no N or P. It does have potassium which is consumed 5 fold more than nitrogen, which is 30-50 fold more concentrated than phosphate. Not all macros need same trace minerals. Iron is always good. Some macros need iodine.

 

[KonradTO]

ChaetoGrow has no N or P. It does have potassium which is consumed 10 fold mor than nitrogen, which is 30-50 fold more concentrated than phosphate. Not all macros need same trace minerals. Iron is always good. Some macros need iodine.

I am dosing Iron tomorrow and I will check Mg this evening. My caulerpa now almost stopped growing, even after I trimmed half of it. On one side its not too bad because I guess I reached the baseline where the amount of nutrients is not enough for more growth, but if I stock more or something dies in the tank then the macro will absorb like crazy the excess nutrient, as long as it is not limited in micro, am I right?

On the other if I will have LPS then I need to either dose N or trim more my caulerpa..

 

[Subsea]

I am dosing Iron tomorrow and I will check Mg this evening. My caulerpa now almost stopped growing, even after I trimmed half of it. On one side its not too bad because I guess I reached the baseline where the amount of nutrients is not enough for more growth, but if I stock more or something dies in the tank then the macro will absorb like crazy the excess nutrient, as long as it is not limited in micro, am I right?

On the other if I will have LPS then I need to either dose N or trim more my caulerpa.

You are correct with both of those generalizations. Micronutrients will limit macro growth. That’s why I add ChaetoGro.

Because I grew Gracilaria Parvispora, Red Ogo, for human consumption, I had it analyzed by a regional agriculture lab.

N at 2.59%
P at 0.082%
K at 13.54%
Ca at 0.555%
Mg at 1.163%
Sulfur at 4.81%
Zn at 139 ppm
Fe at 107 ppm
Mn at 20 ppm
Cu at 7 ppm

 

[KonradTO]

You are correct with both of those generalizations. Micronutrients will limit macro growth. That’s why I add ChaetoGro.

Because I grew Gracilaria Parvispora, Red Ogo, for human consumption, I had it analyzed by a regional agriculture lab.

N at 2.59%
P at 0.082%
K at 13.54%
Ca at 0.555%
Mg at 1.163%
Sulfur at 4.81%
Zn at 139 ppm
Fe at 107 ppm
Mn at 20 ppm
Cu at 7 ppm

It would be interesting to run an empty tank with know elements concentration and then add macro for a certain time and relate growth rate to the nutrient uptake until limiting factor is reached (and which one gets reached first). I mean % composition is interesting but it is the effect of accumulation and does not tell much about the rate of absorption.

A was reading a thread here (https://www.reef2reef.com/threads/m...se-guys-with-stellar-macroalgae-tanks.824253/) where I got some nice inputs.
Instead of opening/closing the connection between planted fuge and DT I guess it would be possible to simulate that by trimming more or less the faster growing macros. I just need to find out how much grams of Caulerpa deplete Nitrogen in X time, then I can keep the right amount of Caulerpa that absorb the right amount of N and P introduced by my stock.

Ok. Maybe it is much more complex than that XD

 

[Randy Holmes-Farley]

Unless your nitrate and phosphate are low, and unless you have measured potassium to be low, I wouldn't randomly dose those.

Iron and manganese are much more likely to be depleted.

 

[KonradTO]

Unless your nitrate and phosphate are low, and unless you have measured potassium to be low, I wouldn't randomly dose those.

Iron and manganese are much more likely to be depleted.

Nitrates are 0, phosphates too. As I wrote above I was thinking to determine how much N my green macros deplete by adding a known amount of N and see how long it takes to be used. Do you think is feasible? How much g/l should I start with? The problem is when it gets depleted faster than I can measure.

 

[Randy Holmes-Farley]

Nitrates are 0, phosphates too. As I wrote above I was thinking to determine how much N my green macros deplete by adding a known amount of N and see how long it takes to be used. Do you think is feasible? How much g/l should I start with? The problem is when it gets depleted faster than I can measure.

Then if you are growing macroalgae for fun, you'll need to dose.

If you are growing it for nutrient reduction, I'd reduce the amount of macroalgae or the lighting period.

Dosing nitrate and phosphate is cheap and easy, when needed. Food grade sodium nitrate and sodium phosphate are my recommendation.

 

[Subsea]

It would be interesting to run an empty tank with know elements concentration and then add macro for a certain time and relate growth rate to the nutrient uptake until limiting factor is reached (and which one gets reached first). I mean % composition is interesting but it is the effect of accumulation and does not tell much about the rate of absorption.

A was reading a thread here (https://www.reef2reef.com/threads/m...se-guys-with-stellar-macroalgae-tanks.824253/) where I got some nice inputs.
Instead of opening/closing the connection between planted fuge and DT I guess it would be possible to simulate that by trimming more or less the faster growing macros. I just need to find out how much grams of Caulerpa deplete Nitrogen in X time, then I can keep the right amount of Caulerpa that absorb the right amount of N and P introduced by my stock.

Ok. Maybe it is much more complex than that XD

Understanding the principals in play enables you to draw those conclusions, however measuring those details is quite complex.

I use bioindicators to assist with diagnosis. If Caulerpa is dull green, I add iron.

Perhapes you should send off your water for ICP testing And remove all doubt.

 

[Duncan62]

I am dosing Iron tomorrow and I will check Mg this evening. My caulerpa now almost stopped growing, even after I trimmed half of it. On one side its not too bad because I guess I reached the baseline where the amount of nutrients is not enough for more growth, but if I stock more or something dies in the tank then the macro will absorb like crazy the excess nutrient, as long as it is not limited in micro, am I right?

On the other if I will have LPS then I need to either dose N or trim more my caulerpa..

Be careful with iron. Feed you fish a varied diet that includes flake food. All your stuff will love it.

 

[Subsea]

Be careful with iron. Feed you fish a varied diet that includes flake food. All your stuff will love it.

This is what Randy Holmes Farley says about iron.

Chemistry And The Aquarium: Iron In A Reef Tank

Randy discusses iron and its usage in our aquariums.

reefs.com

Iron in Reef Tanks: How Much and What Form?​

[Deciding how much iron to add is fairly easy because, in my experience, it doesn’t seem to matter too much. Presumably, once you add enough to eliminate iron as a limiting nutrient, extra iron does not apparently cause harm (at least that I’ve detected in my tanks or heard of from others).]

In my experiences, you can’t overdose iron.

 

[Duncan62]

This is what Randy Holmes Farley says about iron.

Chemistry And The Aquarium: Iron In A Reef Tank

Randy discusses iron and its usage in our aquariums.

reefs.com

Iron in Reef Tanks: How Much and What Form?​

[Deciding how much iron to add is fairly easy because, in my experience, it doesn’t seem to matter too much. Presumably, once you add enough to eliminate iron as a limiting nutrient, extra iron does not apparently cause harm (at least that I’ve detected in my tanks or heard of from others).]

In my experiences, you can’t overdose iron.

I've been told iron with silicate can contribute to cyano outbreaks. I really don't know the science. The tap water in this area is high in Iron though I've never tested for it. Thanks for the Information.

 

[Subsea]

I've been told iron with silicate can contribute to cyano outbreaks. I really don't know the science. The tap water in this area is high in Iron though I've never tested for it. Thanks for the Information.

I am not a chemist, @Randy Holmes-Farley is a doctor of chemistry and an avid hobbiest for 50 yrs.

I am a marine engineer and an avid hobbiest for 50 yrs. I learned before the internet existed. Using Danish philosopher Niels Bore definition of an expert as,

”Someone who has made every possible error in a field of endeavor”.

I can qualify as an expert when it comes to commercial growing Red Ogo, Gracilaria Parvispora seaweed, in a 10K gallon greenhouse growout system for supply to increased demand for fresh seaweed demand in Austin restaurants.

On their own, silicates can fuel diatom growth. I use groundwater which is saturated with silicates from being a shallow inland sea. As I have numerous ornamental sponges and cryptic sponge refugiums, the silicates work in my systems.

@Duncan62
My comment about being difficult to overdose iron, comes from information at the end of the article I linked from Advanced Aquaria written by Randy, where he refers to well document strategies used by seaweed to store iron for lean times. Coral does the same thing with nitrogen storage strategies.

In my case for iron storage, Gracilaria Hayi grown in a monoculture 55G tumble culture growout tank. By mistake, I spilled 250ml of Seachem Iron which immediately dyed water red and I couldn’t see back glass. Within 36 hours, tank water was clear and within 4 days, instead of Hayi being thin lightly calcified, the fronds got thicker and were slightly spongy. After two weeks with no more iron additions Gracilaria Hayi returned to its normal shape,

Marine Plants in the Aquarium

macroalgae, marine plants, caulerpa, refugium substrate, marine macroalgae for sale

www.marineplantbook.com

 

[Randy Holmes-Farley]

I've been told iron with silicate can contribute to cyano outbreaks. I really don't know the science. The tap water in this area is high in Iron though I've never tested for it. Thanks for the Information.

Where did you read that?

I've not seen any evidence that cyanobacteria require or benefit from silicate, and the one scientific paper I read suggested that silicate dosing in a lake decreased cyano and increased diatoms.

Some companies (e.g., Red Sea) and some methods (e.g., Dutch DSR) suggest quite high iron levels (far above natural levels) for various reasons such as phosphate control, and do not apparently suffer from unusual cyano outbreaks.

 

[Duncan62]

Where did you read that?

I've not seen any evidence that cyanobacteria require or benefit from silicate, and the one scientific paper I read suggested that silicate dosing in a lake decreased cyano and increased diatoms.

Some companies (e.g., Red Sea) and some methods (e.g., Dutch DSR) suggest quite high iron levels (far above natural levels) for various reasons such as phosphate control, and do not apparently suffer from unusual cyano outbreaks.

Thanks. As stated above, it's something I've been told by other hobbieists. I definitely am not up for a chemistry debate but I am greatful for your information. I really don't think I'm the only one who associates silicates with cyano. Just saying. But I'll take your word. I'm just lucky my stuff is happy for whatever reason. Thanks again.

 

[Subsea]

”told by other hobbiest” is very far removed from scientific objectivity.

@Duncan62
There is no chemistry debate here. you were given scientific facts from 2 inviduals with 100 years of hands on experience & research as reef hobbiest.