Nitrate and Phosphorus Control via Phytoplankton Additions?

[taricha]

I bought a super sketchy cheap centrifuge for like $60. It's great if things like knobs that stay attached aren't important to you . It only goes up to 4000rpm, but way slower than that would settle phytoplankton in a very short time. On maximum speed symbiodinium cells stay intact, and tiny pods and worms seem unharmed. It can do 6x15mL at a time. This amount of dense live phyto freed of f/2 culture medium would be about what I would want to dose to my 70 Gal and it would take like 2 minutes to do.
(But again, Dana is getting his crazy low N and P results without separating the cells from the growth media. Unexpected.)

 

[sde1500]

I believe the OP's theory was that the increased biodiversity that the phyto was feeding was actually responsible for the nutrient( N&P) reduction, not the phyto itself.

I would agree with this. Same reason new tanks without much life seem to struggle with nuisance growths more than mature tanks. Tanks packed with coral and filter feeder and inverts etc are more balanced and use up more nutrients. Add the same levels of nitrate to a bare tank and a packed tank, the bare tank gets algae, the packed tank eats it through corals and filter feeders. Phyto offering another good food source for the corals and other life theoretically serves to grow that biodiversity.

 

[sde1500]

Skimming through 10 pages with your kids in toe is your fun Neil?
I was only looking for a brief

I said it a bit tongue in cheek, but we're all busy, I work full time, have a 2 year old, and am remodeling my house. It doesn't have to be read in one sitting, but there is a lot of information and discussion here. Going into any long thread and expecting someone to give you a detailed cliff's notes version is acting a little bit entitled. Contributors here have put in the time and effort to share experiences and contribute to the discussion. I don't think it is a big ask for you to put in the effort to consume it.

 

[User]

I bought a super sketchy cheap centrifuge for like $60. It's great if things like knobs that stay attached aren't important to you . It only goes up to 4000rpm, but way slower than that would settle phytoplankton in a very short time. On maximum speed symbiodinium cells stay intact, and tiny pods and worms seem unharmed. It can do 6x15mL at a time. This amount of dense live phyto freed of f/2 culture medium would be about what I would want to dose to my 70 Gal and it would take like 2 minutes to do.
(But again, Dana is getting his crazy low N and P results without separating the cells from the growth media. Unexpected.)

HAs anyone actually done the math? I mean, an almost steady state cukture that’s just about to Ben harvested should have almost completely exhausted the added nutrients. Then factor in the dilution factor- even putting a gallon of straight phyto into a 100 gallon is only 1% increase.I just don’t think ‘contaminating nutrients’ are an issue, unless people are massive overdosing with fertilizer or dumping into the tank the next day after addition


Re: centrifugatiin. 500 rpm is more than enough, but of course, to allow extrapolation to other people machines, we should use RCF (relative centrifugal force, which takes into account the diameter of the swing circle.) 500 rpm at a 9cm rotor diameter is almost 4 times more centrifugal force compared to an 18cm rotor.

 

[Greg P]

How’s that?

Perfect. Thank you

 

[Greg P]

Going into any long thread and expecting someone to give you a detailed cliff's notes version is acting a little bit entitled

I don't feel entitled at all. I was looking for a summary to decide whether the thread is for me.
I would do the same for anyone else.

 

[User]

Perfect. Thank you

lol, ok, glad you approve

 

[taricha]

HAs anyone actually done the math? I mean, an almost steady state cukture that’s just about to Ben harvested should have almost completely exhausted the added nutrients. Then factor in the dilution factor- even putting a gallon of straight phyto into a 100 gallon is only 1% increase.I just don’t think ‘contaminating nutrients’ are an issue, unless people are massive overdosing with fertilizer or dumping into the tank the next day after addition

You can poke around and find a few nutrient depletion curves for nannochloropsis etc. Most of the ones I found showed that Nitrate in f/2-like media was depleted after anywhere from 5-9 days (0 NO3 by day 7 seemed common). and Phosphate could also deplete in that time frame, but more often it looked a little slower to go all the way to zero.
example: https://www.semanticscholar.org/pap...cd1cd55071fc448727ac238fd9f408451985/figure/8

That said, If you dump a Liter of phyto grown on f/2, then you are adding all the nutrients from a liter of f/2 media. It's just that most of it is in phyto cells. But it still all goes in the system. just a question of what happens to it then. I bet some systems would see a definite nutrient increase if they don't have strong export, or a thriving community of phyto eaters etc.

I believe the OP's theory was that the increased biodiversity that the phyto was feeding was actually responsible for the nutrient( N&P) reduction, not the phyto itself.

Tanks packed with coral and filter feeder and inverts etc are more balanced and use up more nutrients.

This may be true, but I'd like to make skeptical noises about it.
What organisms do we think eat phyto, and absorb MORE N and P from system around them when fed phyto?
My guess is most is eaten by zooplankton (pods, etc) that would excrete more waste when fed more phyto. I don't see how that would reduce N and P.

 

[tripdad]

Yes, the more they eat the more they excrete. However some of what they eat is converted into energy for life, so they excrete less than they take in. Therefore they cause a reduction from the initial amount consumed versus that excreted. So the more life forms eating and reproducing causing more to be consumed, then we see a reduction in excess nutrients.

 

[sde1500]

You can poke around and find a few nutrient depletion curves for nannochloropsis etc. Most of the ones I found showed that Nitrate in f/2-like media was depleted after anywhere from 5-9 days (0 NO3 by day 7 seemed common). and Phosphate could also deplete in that time frame, but more often it looked a little slower to go all the way to zero.
example: https://www.semanticscholar.org/paper/Growth,-nutrient-uptake-and-chemical-composition-of-Paes-Faria/d960cd1cd55071fc448727ac238fd9f408451985/figure/8

That said, If you dump a Liter of phyto grown on f/2, then you are adding all the nutrients from a liter of f/2 media. It's just that most of it is in phyto cells. But it still all goes in the system. just a question of what happens to it then. I bet some systems would see a definite nutrient increase if they don't have strong export, or a thriving community of phyto eaters etc.



This may be true, but I'd like to make skeptical noises about it.
What organisms do we think eat phyto, and absorb MORE N and P from system around them when fed phyto?
My guess is most is eaten by zooplankton (pods, etc) that would excrete more waste when fed more phyto. I don't see how that would reduce N and P.

Coral would absolutely eat phyto. And if the extra food they get increases growth then they’d absorb more nutrients from the water too.

 

[taricha]

Coral would absolutely eat phyto. And if the extra food they get increases growth then they’d absorb more nutrients from the water too.

I'm glad the conversation went here. It's a great question, and it's possible Dana might actually know the answer.
@Dana Riddle if we feed a coral colony phyto, will it therefore also consume more NO3 and PO4 from water than if we don't feed it? (excepting the case you posted recently of a coral colony that died without food addition.)

 

[Greg P]

I don't think it is a big ask for you to put in the effort to consume it.

I feel bad for even getting involved to start with. My question was not posed well and my state of mind caused things to go downhill from there.

Let's just pretend I wasn't here and I'll happily follow quietly along

 

[erk]

Just to update with what's been going on so far. I crashed one of my cultures because I didn't harvest enough to allow it to continue growing. I wasn't able to harvest from the culture because I was travelling. With the crashed culture and lack of dosing I have noticed a visible difference in the amount of suspended particles in the water column. Almost 2 weeks without regular phyto dosing due to travel and resurrecting a crashed culture. The tank has suffered greatly without regular dosing, especially this last week as I was on business travel for 3 days. Not sure if this is because I let the skimmer run 24/7 while I was gone or lack of food or maybe both. I'm back to dosing regularly again and hoping I see a turn around soon.

In regards to the crashed culture, I noticed cyano started growing in the culture when it started dying. I think this exasperated the issue as the cyano was competing with the nanno for nutrients.

 

[User]

Coral would absolutely eat phyto. And if the extra food they get increases growth then they’d absorb more nutrients from the water too.

Isn't the growth due to the nutrients in the phyto though? It's not like they can just start sucking up free nitrate from the water column...

 

[tripdad]

I think it's fairly accepted that corals can take nutrients from the water column directly.

 

[sde1500]

It's not like they can just start sucking up free nitrate from the water column...

I am fairly positive they can.

 

[User]

I am fairly positive they can.

Wasn’t aware it would be a substantial amount. Thanks

 

[VR28man]

I dozed phyto pretty consistently for one or two months prior to a tank crash two weeks ago. After a while, I started getting skimmate that looks like this (old-school glass tube and wood airstone).

It seems that I was just skimming out all of the phyto I was putting in?

[photo to follow; I thought I had it!!!!]

Edited to Add: still can't find it!!!! I must have accidentally deleted the photo. And post tank crash my skimmate looks completely different (and I'm not dosing phyto either)

And for more detail per @sde1500 : yeah, my skimmate used to be dark olive green (almost army color), but after like a week of phytodosing the hue of green changed to almost exactly the same bright forest-green hue of the Kent phytoplankton.

 

[sde1500]

I dozed phyto pretty consistently for one or two months prior to a tank crash two weeks ago. After a while, I started getting skimmate that looks like this (old-school glass tube and wood airstone).

It seems that I was just skimming out all of the phyto I was putting in?

It is possible that you are skimming some out, but my skimmate always looked a dark green color similar in color to the phyto I added. Even before I was adding phyto.

 

[Dana Riddle]

I dozed phyto pretty consistently for one or two months prior to a tank crash two weeks ago. After a while, I started getting skimmate that looks like this (old-school glass tube and wood airstone).

It seems that I was just skimming out all of the phyto I was putting in?

[photo to follow; I thought I had it!!!!]

Edited to Add: still can't find it!!!! I must have accidentally deleted the photo. And post tank crash my skimmate looks completely different (and I'm not dosing phyto either)

And for more detail per @sde1500 : yeah, my skimmate used to be dark olive green (almost army color), but after like a week of phytodosing the hue of green changed to almost exactly the same bright forest-green hue of the Kent phytoplankton.

I saw the same thing when running the skimmer continuously - the bottom of the skimmer cup was coated with phyto, hence I don't run the skimmer during the day.