Advice Needed! Phosguard Versus Algae Scrubber

[Randy Holmes-Farley]

Randy as someone who has never run a scrubber please leave your advice out of this. We deal with this on a daily basis and have advised thousands how to turn around their nutrient uptake. The redfield ratio along with having the correct amount of trace elements factors into growth and uptake more than your books can teach you!

Then you misuse the Redfield ratio on a daily basis.

You are certainly welcome to your opinion, and are welcome to back it up with any sort of information you choose. As am I.

Let me ask you a question to help you and others understand what I believe is incorrect before you just reflexively reject my comment.

Suppose that you have everything at your preferred ratio. Yes, algae in the scrubber will grow fine.

Then you add some extra nitrate by dosing it. You are no longer at your preferred ratio.

Is there any scenario where the algae grows more slowly because you are no longer at that preferred ratio but everything else remained the same?

If you view it differently, as in having enough N and P so that neither one is limiting, that seems to solve the problem.

 

[Randy Holmes-Farley]

I'm a bit confused by the GARF paper, but if it is taken literally as written, they see algae growth rising as phosphate rises up to about 0.2% P (Figure 6).

Really? Is that a typo, or are they really looking at phosphate levels above 2,000 ppm P (>6,000 ppm phosphate). Did I misunderstand it?

It sure wouldn't surprise me that phosphate at that level caused all kinds of bad stuff. Force feeding of P, precipitation of iron phosphate, etc.

 

[Randy Holmes-Farley]

It can but it can also lead to other issues. What we have seen is that corals don’t usually like the immediate drop caused from gfo. However quick drops with natural filtration has not affected them in such a manner.

Why is that, do you think? How does a coral know what removed the phosphate?

IMO, the issue is the drop extent and speed, regardless of how it happened.

 

[Dan_P]

There are so many unanswered questions with regard to scrubbers.



You mean something like this rabbit hole;

Too much phosphate ?

This experiment seems to indicate reduced algae growth at increased phos levels; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3434001/ wouldnt this indicate that once a tipping point has been reached, you'll never get enough growth to reduce it ? Don't mind if I'm wrong on this by the way, but...

algaescrubber.net

Oh my! The referenced paper on this post is a gem. Thanks

 

[BroccoliFarmer]

someone above stated: as someone who has never run a scrubber

honest question and not trying to troll. But anyone who runs a macro algae fuge be knowledgeable enough to speak to N and P uptake? I honestly don’t understand the statement. What magic does a scrubber do that macro in a fuge does not. As someone who has run both they use the same bio mechanisms to pull nutrients from the water.

ok. Maybe a little troll. Let’s say 97% honest question 3% troll.

 

[HB AL]

Randy as someone who has never run a scrubber please leave your advice out of this. We deal with this on a daily basis and have advised thousands how to turn around their nutrient uptake. The redfield ratio along with having the correct amount of trace elements factors into growth and uptake more than your books can teach you!

Take a deep breathe, relax. I do my own thing my way but always read any articles, etc... that Randy posts as he's always a straight shooter and isn't posting up posts to make money off the forum so I listen to him versus the many vendors that post on here to steer people to there products they represent for the sole reason of the mighty dollar.

 

[HB AL]

Not singling out any specific companies but for what the actual hardware is and how an algae scrubber works they have to be one of the most overpriced pieces of equipment a reefer could buy.

 

[Garf]

I'm a bit confused by the GARF paper, but if it is taken literally as written, they see algae growth rising as phosphate rises up to about 0.2% P (Figure 6).

Really? Is that a typo, or are they really looking at phosphate levels above 2,000 ppm P (>6,000 ppm phosphate). Did I misunderstand it?

It sure wouldn't surprise me that phosphate at that level caused all kinds of bad stuff. Force feeding of P, precipitation of iron phosphate, etc.

I’m pretty sure the 0.2% figure is tissue content of the algae, not the water. The enrichment looks like it reached 0.28 ppm P, for 50% of the growth experiment, in pulses. I posted that on the scrubber site 10 years ago hoping someone could clarify as I assumed someone would know, I was wrong

 

[EeyoreIsMySpiritAnimal]

Not singling out any specific companies but for what the actual hardware is and how an algae scrubber works they have to be one of the most overpriced pieces of equipment a reefer could buy.

Well, those and ATO reservoirs, lol!

 

[EeyoreIsMySpiritAnimal]

Randy as someone who has never run a scrubber please leave your advice out of this. We deal with this on a daily basis and have advised thousands how to turn around their nutrient uptake. The redfield ratio along with having the correct amount of trace elements factors into growth and uptake more than your books can teach you!

Whelp, you've lost all credibility with this post!

 

[EeyoreIsMySpiritAnimal]

Randy as someone who has never run a scrubber please leave your advice out of this. We deal with this on a daily basis and have advised thousands how to turn around their nutrient uptake. The redfield ratio along with having the correct amount of trace elements factors into growth and uptake more than your books can teach you!

You might also want to learn what the redfield ratio really applies to...

Redfield ratio as it pertains to the reef or your reef is stupid and pointless

This Redfield ratio thing always pops up on here and every other forum. For some reason many people have been convinced that it has something to do with reef tanks, let alone actual reefs. The Redfield ratio is about the consistent molar ratio between carbon, nitrogen and phosphate of the deep...

www.reef2reef.com

 

[Someshmuk]

I run an algae turf scrubber and a protein skimmer as my nutrient management. Seems to be working since I haven't check nutrients in a good year+ and my acros have better polyp extension and color than when i was chasing nutrient control. The only maintinance I have to do for either is cleaning the screen on the ATS and the cup for the skimmer.

The name of the game is stability and an ATS is a stabilizing control on nitrates and phosphates. I haven't seen any indicators from any of my corals that i'm bottoming out nutrients so theres a self regulating function built into an ATS.

 

[BroccoliFarmer]

Not singling out any specific companies but for what the actual hardware is and how an algae scrubber works they have to be one of the most overpriced pieces of equipment a reefer could buy.

I agree. For what it does vs a cheapie grow light over a fuge is very much a waste of money.

One positive thing I will say about an algae scrubber is that it helped cure my gha infestation in my sump. All gha not in scrubber went away. i have since removed it and sold it as it didn’t do anything more than my chaeto.

 

[GARRIGA]

I’ve found that carbon dosing keeps my nitrates under 5 ppm and phosphates under 0.25 ppm. Experimental tank and don’t need precise phosphates at the moment but have found that for my setup carbon dosing can actually zero out my nitrates but that can be resolved by periodically adjusting the dosage and trying to keep feeding about the same.

Much easier for me to overfeed then add nitrates and/or phosphates as needed than trying to pinpoint an exact carbon dosage or amount of GFO or PhosGuard to get everything dialed in perfectly.

Caveat, no WC or skimmer therefore mileage on phosphates and carbon dosing may vary and I’ve had to use lanthanum chloride when phosphates have gotten higher and didn’t want to wait on carbon dosing to solve it. Again. Easier to bottom something out for me and add then trying to get subtraction correct.

 

[BroccoliFarmer]

I’ve found that carbon dosing keeps my nitrates under 5 ppm and phosphates under 0.25 ppm. Experimental tank and dint need precise phosphates at the moment but have found that for my setup carbon dosing can actually zero out my nitrates but that can be resolved by periodically adjusting the dosage and trying to keep feeding about the same.

Much easier for me to overfeed then add nitrates and/or phosphates as needed then trying to pinpoint an exact carbon dosage or amount of GFO or PhosGuard to get everything dialed in perfectly.

Caveat, no WC or skimmer therefore mileage on phosphates and carbon dosing may vary and I’ve had to use lanthanum chloride when phosphates have gotten higher and didn’t want to wait on carbon dosing to solve it. Again. Easier to bottom something out for me and add then trying to get subtraction correct.

+1

 

[Randy Holmes-Farley]

I’m pretty sure the 0.2% figure is tissue content of the algae, not the water. The enrichment looks like it reached 0.28 ppm P, for 50% of the growth experiment, in pulses. I posted that on the scrubber site 10 years ago hoping someone could clarify as I assumed someone would know, I was wrong

OK, THat's seems a lot more sensible, but I still don't understand the graph then. Table 1 lists only 3 conditions but the graph has more than 3 data points. What are they from?

Anyway, Figure 5 does show that neither N (as urea) nor P are limiting to total growth, which means something else is limiting. High phosphate does show a growth decline.

 

[ReefGeezer]

The thing is, I have a big phosphate problem. Phosphate is at .25ppmand nitrate is at 4.2ppm...

...I have heard positives and negatives about both. On the one hand, I love the natural approach with the algae scrubber, but I am worried it will bottom out my nitrates. On the other hand, I feel the Phosguard will solve my problem, but I am worried about bottoming out my phosphates and I feel like it may be a short-term solution when I need something sustainable.

Any thought or suggestions?

So, using natural methods i.e. Cheato, Algae Turf Scrubbers, and carbon dosing might not be optimal for your situation. All those methods use nitrogen as well as phosphate. I think too, they use more nitrogen in relation to phosphate. While nitrate won't immediately limit the process, it's a good bet that it will in the future. Like many have said, Phosguard, GFO, or some other phosphate binding media would be the best bet. There is a third option... Lanthanum Chloride dosing. It is capable of reducing free phosphate levels at a controllable pace. Read up on it though. It has some risks and requires the reefer to be careful.

 

[Garf]

OK, THat's seems a lot more sensible, but I still don't understand the graph then. Table 1 lists only 3 conditions but the graph has more than 3 data points. What are they from?

Anyway, Figure 5 does show that neither N (as urea) nor P are limiting to total growth, which means something else is limiting. High phosphate does show a growth decline.

These algae under test were used to really low nutrients, I suppose it could be an acclimation type scenario. They stored P at the expense of growth, it appears, perhaps preparing for leaner times. May have absolutely no relevance to a tank or scrubbers except where P fluctuates like a fiddlers elbow. Yes the charts do seem to have more data points than the tests suggest possible, which is odd. My assumption was extra testing was carried out and plotted but not described in the text, just another mystery, lol.

 

[EeyoreIsMySpiritAnimal]

I run an algae turf scrubber and a protein skimmer as my nutrient management. Seems to be working since I haven't check nutrients in a good year+ and my acros have better polyp extension and color than when i was chasing nutrient control. The only maintinance I have to do for either is cleaning the screen on the ATS and the cup for the skimmer.

The name of the game is stability and an ATS is a stabilizing control on nitrates and phosphates. I haven't seen any indicators from any of my corals that i'm bottoming out nutrients so theres a self regulating function built into an ATS.

I'm glad your tank is doing well and I agree that chasing numbers is not the best policy, but if you "haven't checked nutrients in a good year+", then how can you say for sure that your nutritients are stable?

 

[Dan_P]

I'm a bit confused by the GARF paper, but if it is taken literally as written, they see algae growth rising as phosphate rises up to about 0.2% P (Figure 6).

Really? Is that a typo, or are they really looking at phosphate levels above 2,000 ppm P (>6,000 ppm phosphate). Did I misunderstand it?

It sure wouldn't surprise me that phosphate at that level caused all kinds of bad stuff. Force feeding of P, precipitation of iron phosphate, etc.

The paper is providing data that shows the growth rate hypothesis does not apply to three macro algae species. The hypothesis says that growth rate is correlated to RNA amount is correlated to internal phosphorous amount (dry weight). That’s failure is OK because the GRH is a bold hypothesis linking internal element amount to a very complex process, growth.

The hypothesis belongs to the science of biological stoichiometry and related to ecological stoichiometry where the Redfield ratio lurks. As these sciences gather more information, it looks more and more like the Redfield ratio is a grand average of stoichiometric ratios and not a fundamental insight into ocean life.