Phytoplankton culture water?

[Jay Hemdal]

Hi folks,

I have a general question that's been bugging me for some time now. I've grown various phytoplankton cultures for 30+ years. I use them to feed rotifer or copepod cultures for raising larval fish. Typically, I use a modified Guilliards f2 nutrient growth material.

I hear people are adding phyto cultures to their reefs now. How do you avoid adding excess nutrients and waste products from the culture water? I tried micron filtration and even centrifuge, but wasn't pleased with the results......

Thanks,

Jay

 

[Mhamilton0911]

I just recently started a phyto culture and out of curiosity I set up a test for NO4 and PO3 and found no detecable amounts. Even with a high concentration. I am using just salifert tests though. And 7 day phyto. I'm assuming the phyto used all the fertilizer in that 7 days.

I first tested plain fresh saltwater, 0 for both nitrate and phosphate. Then I added 1ml to a quart of fresh saltwater. Still 0 for both. I upped to 5ml/ quart of saltwater, still 0 for both. I again upped to 10ml phyto to 1 quart saltwater, still testing 0 nitrate and phosphate.

So by my math, at the 10ml/qt dose, that's 40ml per gallon, I have a 29g tank, I'd have to dose 1160ml to my 29g to get the same concentration, thats more than a quart of phyto into my tank, which will never happen. I feel confident adding my shotglass worth of phyto and not adding extra nutrients.


What nutrients or waste products are you worried about specifically?

 

[Jay Hemdal]

I just recently started a phyto culture and out of curiosity I set up a test for NO4 and PO3 and found no detecable amounts. Even with a high concentration. I am using just salifert tests though. And 7 day phyto. I'm assuming the phyto used all the fertilizer in that 7 days.

I first tested plain fresh saltwater, 0 for both nitrate and phosphate. Then I added 1ml to a quart of fresh saltwater. Still 0 for both. I upped to 5ml/ quart of saltwater, still 0 for both. I again upped to 10ml phyto to 1 quart saltwater, still testing 0 nitrate and phosphate.

So by my math, at the 10ml/qt dose, that's 40ml per gallon, I have a 29g tank, I'd have to dose 1160ml to my 29g to get the same concentration, thats more than a quart of phyto into my tank, which will never happen. I feel confident adding my shotglass worth of phyto and not adding extra nutrients.


What nutrients or waste products are you worried about specifically?

f2 media has a number of things I wouldn't want to add to my tank:

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ncma.bigelow.org

My guess is that when people make this up for phyto culture, they drop the silica, but IDK for sure.

I'm worried because phyto cultures crash in an absence of nutrients, so if I'm adding a fresh culture, I know I must be adding some nutrients as well. In addition, technically, the phyto doesn't remove nutrients, it only sequesters it. My nutrient mixes are pretty rich. Those nutrients get bound up in the phyto cells, but they are still there in the culture.

I'm not sure I can test culture water on my spectrophotometer - the base color of the culture itself may interfere.

So here is the basic conundrum: People take great care to only use RO/DI water in their reef tank, but then go and pour in some grody phyto culture water....


Jay

Jay

 

[sixty_reefer]

Hi folks,

I have a general question that's been bugging me for some time now. I've grown various phytoplankton cultures for 30+ years. I use them to feed rotifer or copepod cultures for raising larval fish. Typically, I use a modified Guilliards f2 nutrient growth material.

I hear people are adding phyto cultures to their reefs now. How do you avoid adding excess nutrients and waste products from the culture water? I tried micron filtration and even centrifuge, but wasn't pleased with the results......

Thanks,

Jay

Hi jay, are you mainly concerned with the traces from the f2 contamination?

 

[Mhamilton0911]

I ran my test for nitrate and phosphate because that's the number one thing I gathered from many hours of reading was that dosing phyto could raise those nutrients. I actually have a starved system and could use those extra nutrients. I should be adding nitrate and phosphate to get any detecable readings, but I haven't been dosing those lately, I'm trying to get those up naturally.

 

[Jay Hemdal]

Hi jay, are you mainly concerned with the traces from the f2 contamination?

Yes, as well as the nutrients bound up in the algae cells themselves. Then, what about phenols/cresols and other waste products that can’t be measured? Algae cells are pretty “leaky” and let some materials escape….
Jay

 

[HuduVudu]

I used calcium nitrate or magnesium nitrate for a nutrient source.

 

[sixty_reefer]

Yes, as well as the nutrients bound up in the algae cells themselves. Then, what about phenols/cresols and other waste products that can’t be measured? Algae cells are pretty “leaky” and let some materials escape….
Jay

As far as getting a cleaner culture of phytoplankton there is two ways.
One is to use a product called TNC Complete aquarium plant food (it’s mainly used in freshwater) I find the formula clean and grows phytoplankton really well.
the second if the goal is to grow rotifers and copepod in large numbers I would suggest freeze dried phytoplankton, it’s more expensive although it can’t be better than that as they are produced using seawater.
In relation to demineralisation almost everything is used by organism including bacteria in aquaria and what’s not it becomes stored as detritus (carbon stored).
are you observing a issue in nutrients on your breeding tanks? As this could be one of the side effects of large phytoplankton additions