Advice Needed! Phosguard Versus Algae Scrubber

[Randy Holmes-Farley]

Thanks Dan. I’m not sure what was limiting growth here , but there are plenty of papers where adding N or P or both to natural seawater boost growth of various species of macroalgae.

 

[Garf]

Thanks Dan. I’m not sure what was limiting growth here , but there are plenty of papers where adding N or P or both to natural seawater boost growth of various species of macroalgae.

My scrubber grew just great at 60ppm nitrate and 1ppm phos, which is a fair departure from redfield, lol. It also grew great at 15ppm N, 0.15ppm P. However there would have been no acclimation issues here.

I have long believed that algal exudates produced by green stuff should probably be kept away from coral, as far as possible. Not just algal exudates, in fact most if not all coral exudates also. A separate recirculating sump section chocked with non porous bio media to consume the exudates (and produce bacterial flocks as a consequence), perhaps. I’ve Been running an upside down trickle filter for 6 months, for this purpose (but not running a scrubber) and appears to digest proteinous stuff just fine.

 

[Josh@ClearWaterScrubbers]

For one thing we have peer reviewed information from Randy versus anecdotal information from a vendor. Not sure this puts you in a strong position to invalidate Randy’s advice.

Just because you use the Redfield ratio to formulate advice for your customers is not a very strong case that the Redfield ratio is relevant to adjusting an algae scrubber.

And finally, I have to wonder that you need to advise so many customers on a daily basis. This does not speak highly of the methodology you are selling. Maybe what Randy is saying or further civil discussion could result in an improved operation of your product.

For one thing we have peer reviewed information from Randy versus anecdotal information from a vendor. Not sure this puts you in a strong position to invalidate Randy’s advice.

Just because you use the Redfield ratio to formulate advice for your customers is not a very strong case that the Redfield ratio is relevant to adjusting an algae scrubber.

And finally, I have to wonder that you need to advise so many customers on a daily basis. This does not speak highly of the methodology you are selling. Maybe what Randy is saying or further civil discussion could result in an improved operation of your product.

How do you have anything peer reviewed from Randy when he’s NEVER ran an ATS?

Maybe you should as to see Randy’s tank before defending him like he’s a god of reefing…

 

[Randy Holmes-Farley]

How do you have anything peer reviewed from Randy when he’s NEVER ran an ATS?

Maybe you should as to see Randy’s tank before defending him like he’s a god of reefing…

Wow, you really are looking to pick a fight, aren't you.

Have you seen my tank? Do you have a criticism of it? What criticism?

While it is NEVER appropriate to judge the correctness of scientific comments by the keeper of a reef tank by looking at the tank he or she keeps (people do right things for wrong reasons all the time, and many reef tanks thrive despite inaccurate understanding of what is happening), I think my reef tank operated just fine for 20 years. It did not use an ATS (I grew macroalgae in refugia), but I never thought an ATS would have made it worse (or better) than growing macroalgae.

You may have a great tank. You may have thousands of customers with great tanks. That does not make your misuse of the Redfield ratio a correct principle.

 

[ninjamyst]

How do you have anything peer reviewed from Randy when he’s NEVER ran an ATS?

Maybe you should as to see Randy’s tank before defending him like he’s a god of reefing…

Picking fights on a public forum is not a good marketing strategy. Never heard of your company but I did just Google it and will stay away from it. It doesn't matter at this point whether you are right or wrong. It's PR management.

 

[Garf]

How do you have anything peer reviewed from Randy when he’s NEVER ran an ATS?

Maybe you should as to see Randy’s tank before defending him like he’s a god of reefing…

I spent many hours looking over the research of folks that are paid to research this ratio in algae. It appeared that the ratio not only changed with species but also location, temperature, ph, light, nutrient availability and even associated bacterial communities. I gave up trying to figure it out as there were too many variables.
I also added CO2 which appeared to make the algae heavier per unit of growth. I concluded extreme CO2 skewed the carbon content but the more I looked into that, the more I realized how little I really knew.

On another note, have you tried feeding a scrubber with water laden with air bubbles (Venturi or something similar) ? Grows great

 

[BroccoliFarmer]

I am really dumbfounded that someone claiming to represent a company could be this combative on a public forum. It’s almost like he doesn’t know the internet. Especially when his product has the same essential processes of a fuge with macro. To claim superior knowledge because you are selling a piece of equipment that is legitimately not needed and is redundant to what many people do and have been successful at …you’d think you would make up with charm and knowledge to compensate for the waste of money.
Of well, good luck. Hopefully your public aggressiveness to someone that is genuinely trying to help others comes back with some karma.

 

[EeyoreIsMySpiritAnimal]

How do you have anything peer reviewed from Randy when he’s NEVER ran an ATS?

Maybe you should as to see Randy’s tank before defending him like he’s a god of reefing…

Are you trying to alienate the R2R community so we won't buy your product? Because it's working...

 

[Oldreefer44]

To answer the original question:
My experience with an Algae scrubber, Phosgard, as well as a CO2 scrubber was the difficulty maintaining a stable amount of PO4. With all of these there was a cycle of effectiveness that caused my PO4 to go up and down. IMO, stability is more important that getting to a certain number (within reason). I am currently dosing Phosphate-E daily and while I am still trying to nail down the exact dosage I am finding it to be an easier way of keeping the "number" stable.

 

[Turbo's Aquatics]

I couldn’t resist

 

[killer2001]

I call my urchin the algae scrubber.

 

[Rams]

How do you have anything peer reviewed from Randy when he’s NEVER ran an ATS?

Maybe you should as to see Randy’s tank before defending him like he’s a god of reefing…

You lost your credibility man..never ran algae scrubber and I won’t after seeing your comments.if I have to I will just DIY.

 

[EeyoreIsMySpiritAnimal]

I couldn’t resist

Aren't you the co-owner with Josh?

 

[SantaMonica]

There are a few things which cause a non-linear N/P ratio growth effect in algae, and thus, nutrient uptake. Luxury Uptake is one, but in the particular case of scrubbers, the darkening effect on the growth, from any excess nutrient, blocks light and therefore changes the ongoing growth/absorption pattern of all algae that is under/below that darkened growth.

 

[Randy Holmes-Farley]

There are a few things which cause a non-linear N/P ratio growth effect in algae, and thus, nutrient uptake. Luxury Uptake is one, but in the particular case of scrubbers, the darkening effect on the growth, from any excess nutrient, blocks light and therefore changes the ongoing growth/absorption pattern of all algae that is under/below that darkened growth.

That's an interesting idea, and it seems to support the hypothesis that the Redfield ratio (or any ratio ) is not the best way to think about it since higher nutrients at any fixed ratio may cause darkening relative to lower nutrients at the same ratio. I think it goes back to the idea that trying to keep both N and P in desirable absolute ranges (e,g., 2 to 10 ppm nitrate and 0.02 to 0.1 ppm phosphate, or whatever ranges folks prefer) is unlikely to ever be worse than targeting ratios of any kind independent of the absolute values.

Do you have any idea of the magnitude of the effect you are talking about?

For it to be significant, some fairly complicated things need to happen...

Darkening of algae in elevated nutrients is presumably from additional chlorophyll and the algae trying to take advantage of the available nutrients. Absolute concentrations of chlorophyll in the ocean is often taken as a good measure of the local productivity of photosynthesis. So that would be different here.

For there to be a darkening effect that reduces overall productivity, one would need that the chlorophyll in the upper layers of algae are absorbing light but not using it as effectively for growth as a lower down algae would. That could possibly be the case, if the algae is getting all the chemical energy it can handle and is wasting some excess. I've never looked to see if that sort of thing is known to happen with excess nutrients.

I know that organisms do have protective mechanisms when there is too much light which removes the excess energy to prevent damage. But I've not seen an indication that higher nutrients could trigger such effects

Harnessing the right amount of sunshine

Researchers from MIT and the University of Verona have discovered how a key photoprotection protein allows moss and green algae to protect themselves from too much sun by dissipating the extra energy as heat. Learning more about how this protein works could allow scientists to alter it in a way...

news.mit.edu

"The researchers found that the protein, embedded in the membranes in the chloroplast, can switch between different states in response to changes in sunlight. When moss and green algae absorb more sunlight than they need, this protein releases the energy as heat, preventing it from building up and damaging the cells. The protein can act within seconds of a change in sun exposure, such as when the sun appears from behind a cloud."

The other thing needed is that not only are the lower down algae more efficient, but they would need to be enough more efficient to offset other losses of light (e.g., absorption, scattering, reflection back up) while passing through the first algae bodies before it gets to algae deeper down.

I personally would not have predicted this overall effect to happen (that is, decreased growth due to greening up of the algae) , but it is certainly a plausible effect.

 

[Garf]

That's an interesting idea, and it seems to support the hypothesis that the Redfield ratio (or any ratio ) is not the best way to think about it since higher nutrients at any fixed ratio may cause darkening relative to lower nutrients at the same ratio. I think it goes back to the idea that trying to keep both N and P in desirable absolute ranges (e,g., 2 to 10 ppm nitrate and 0.02 to 0.1 ppm phosphate, or whatever ranges folks prefer) is unlikely to ever be worse than targeting ratios of any kind independent of the absolute values.

Do you have any idea of the magnitude of the effect you are talking about?

For it to be significant, some fairly complicated things need to happen...

Darkening of algae in elevated nutrients is presumably from additional chlorophyll and the algae trying to take advantage of the available nutrients. Absolute concentrations of chlorophyll in the ocean is often taken as a good measure of the local productivity of photosynthesis. So that would be different here.

For there to be a darkening effect that reduces overall productivity, one would need that the chlorophyll in the upper layers of algae are absorbing light but not using it as effectively for growth as a lower down algae would. That could possibly be the case, if the algae is getting all the chemical energy it can handle and is wasting some excess. I've never looked to see if that sort of thing is known to happen with excess nutrients.

I know that organisms do have protective mechanisms when there is too much light which removes the excess energy to prevent damage. But I've not seen an indication that higher nutrients could trigger such effects

Harnessing the right amount of sunshine

Researchers from MIT and the University of Verona have discovered how a key photoprotection protein allows moss and green algae to protect themselves from too much sun by dissipating the extra energy as heat. Learning more about how this protein works could allow scientists to alter it in a way...

news.mit.edu

"The researchers found that the protein, embedded in the membranes in the chloroplast, can switch between different states in response to changes in sunlight. When moss and green algae absorb more sunlight than they need, this protein releases the energy as heat, preventing it from building up and damaging the cells. The protein can act within seconds of a change in sun exposure, such as when the sun appears from behind a cloud."

The other thing needed is that not only are the lower down algae more efficient, but they would need to be enough more efficient to offset other losses of light (e.g., absorption, scattering, reflection back up) while passing through the first algae bodies before it gets to algae deeper down.

I personally would not have predicted this overall effect to happen (that is, decreased growth due to greening up of the algae) , but it is certainly a plausible effect.

howdy from the uk - day one - Page 15

thought i would chip in and let you comment on my effort so far. Backgroung of display- 5 x 2 x 2 with 240 ltr sump containing skimmer (massively inefficient), DSB in display (silica play sand), approx 100 kgs live rock. Most corals are 7 years old and all fish but 2 of the tangs, are of...

algaescrubber.net

 

[Dan_P]

That's an interesting idea, and it seems to support the hypothesis that the Redfield ratio (or any ratio ) is not the best way to think about it since higher nutrients at any fixed ratio may cause darkening relative to lower nutrients at the same ratio. I think it goes back to the idea that trying to keep both N and P in desirable absolute ranges (e,g., 2 to 10 ppm nitrate and 0.02 to 0.1 ppm phosphate, or whatever ranges folks prefer) is unlikely to ever be worse than targeting ratios of any kind independent of the absolute values.

In addition to luxury uptake causing changes to an N/P uptake ratio, the growth rate and health of the plant also change the uptake ratio. In addition to this confounded factor, algae scrubbers are rarely ever a single species with all the individuals growing at the same rate. By now we can begin to see why the uptake N/P ratio is a meaningless term.

One serious issue causing wildly different growth rates is self-shading. When trying to grow dense communities of any photosynthetic organism, self-shading is always something you have to deal with. And because of this variation in light intensity, the N/P ratio is meaningless.

Another aspect of dense benthic algae communities is nutrient availability. As the mat thickens in an algae scrubber, diffusion of nutrients and waste begins to slow down. Over time other organisms that can live under these nutrient choked areas move in. Growth of cyanobacteria is probably an indication that the algae is suffering which in turn means that the N/P uptake ratio is changing in that region of the mat. This is when higher nutrient concentration, not a change in N/P ratio, could benefit those plants located lower in the mat. But why would you dose nutrients to an algae scrubber whose job it is to remove nutrients? Algae scrubbers might be thought of as algae-slime scrubbers because of this declining nutrient availability that occurs as the the algae growth becomes denser and nutrient availability declines.

 

[Jposch]

In addition to luxury uptake causing changes to an N/P uptake ratio, the growth rate and health of the plant also change the uptake ratio. In addition to this confounded factor, algae scrubbers are rarely ever a single species with all the individuals growing at the same rate. By now we can begin to see why the uptake N/P ratio is a meaningless term.

One serious issue causing wildly different growth rates is self-shading. When trying to grow dense communities of any photosynthetic organism, self-shading is always something you have to deal with. And because of this variation in light intensity, the N/P ratio is meaningless.

Another aspect of dense benthic algae communities is nutrient availability. As the mat thickens in an algae scrubber, diffusion of nutrients and waste begins to slow down. Over time other organisms that can live under these nutrient choked areas move in. Growth of cyanobacteria is probably an indication that the algae is suffering which in turn means that the N/P uptake ratio is changing in that region of the mat. This is when higher nutrient concentration, not a change in N/P ratio, could benefit those plants located lower in the mat. But why would you dose nutrients to an algae scrubber whose job it is to remove nutrients? Algae scrubbers might be thought of as algae-slime scrubbers because of this declining nutrient availability that occurs as the the algae growth becomes denser and nutrient availability declines.

In the OP's case. I wouldn't. Same as for most other situations when both main nutrients are in excess. Regardless of ratio.
If N or P are truly 0, then yes. A well established scrubber can strip 1 or the other very effectively, thus leading to an N or P limitation.
The multi-species community on a scrubber is another major factor not thought about by desktop experts. Even those who manufacture scrubbers. If nutrients are exceeding the capability of a scrubber, rather than buying a larger unit, you can just change the photo period to be multiple shorter periods with short rests of 15mins or so in between. Alage are simple and unlike coral, don't require "a full night's rest." Example:4hr on, 15mins off, round the clock, 24/7. Doing this can near double the growth and nutrient uptake for a screen size.
Need proof? Just try it yourself. ‍
I suggested this method to @jlanger and it worked incredibly well for him as well.

 

[Jposch]

*not sure why it changed the emoji. Lol

 

[GARRIGA]

Alage are simple and unlike coral, don't require "a full night's rest." Example:4hr on, 15mins off, round the clock, 24/7.

Tried a 24/7 cycle on freshwater green water and plants both submerged and floating and after several months found no ill affects yet my parameters remained stable. Got the idea from pot growers. Those guys are pushing the boundary on lighting plus Reef Builders run their chaeto refugium 24/7. Was thinking slime algae found on scrubbers should work the same.

Benefit of 24/7 being one could run the lights off ph values by only turning off photosynthesis when ph exceeds certain thresholds. Research has shown that plants in freshwater continue to take certain nutrients in the absence of light although not sure how that works with marine macro algae and if those nutrients are still removed during photosynthesis periods.

As you said. Just try it and how I approach many issues that seem controversial including those that have an established mantra yet logically it might work differently if approached differently. Experience being the best teacher because what we thought yesterday might not be the same tomorrow. Knowledge changes with new experiences.