Phytoplankton nutrition

[Bubba shrimp]

Hi my name is Gavin and this is my first post. I am running a shrimp farm in the UK.
We have reduce nitrates from 400 mg/l to 20 mg/l and are starting to see a reduction in phytoplankton growth. I have results of a water sample we had analysed. Looking for advice on what if anything I should test for / dose.

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[Bubba shrimp]

Saltwater test results from diy salt mix

 

[Randy Holmes-Farley Verified Community Expert]

What did you do to reduce the nitrate?

 

[Bubba shrimp]

What did you do to reduce the nitrate?

Turned off circulation pump to rest the water which aloud the phytoplankton to become dominant. We have 10 4000ltr tanks ras system with settlement Chambers and moving beds for filtration. One large 20000 ltr denitrification tank. That only works when offline from production tanks.
My question really is what are the main elements / components i need to monitor to keep the green water active without crashes.

 

[DxMarinefish]

What are you feeding the Phyto with?
Phyto need more than light at the correct spectrum, they need plat based fertiliser, and lots of it dosed at the correct amount and the correct interval.
They also need aeration.

 

[Bubba shrimp]

What did you do to reduce the nitrate?

Turned off circulation pump to rest the water which aloud the phytoplankton to become dominant. We have 10 4000ltr tanks ras system with settlement Chambers and moving beds for filtration. One large 20000 ltr denitrification tank. That only works when offline from production tanks.
My question really is what are the main elements / components i need to monitor to keep the green water active without crashes

Turned off circulation pump to rest the water which aloud the phytoplankton to become dominant. We have 10 4000ltr tanks ras system with settlement Chambers and moving beds for filtration. One large 20000 ltr denitrification tank. That only works when offline from production tanks.
My question really is what are the main elements / components i need to monitor to keep the green

What are you feeding the Phyto with?
Phyto need more than light at the correct spectrum, they need plat based fertiliser, and lots of it dosed at the correct amount and the correct interval.
They also need aeration.

We haven't ever used any feed other than shrimp feed approx 5kg daily.
Good supply of ammonia nitrites and 20ppm nitrate. Ammonia and nitrite being 0.25ppm. Phosphate above 10ppm limits of my test but well above. I'm going to test for silicate as I've read that can be a limiting nutrition.
As we are missing most minor elements i was hoping for any advice on which if any are needed or are consumed by phytoplankton.

 

[MBruun]

Apart from light, nitrate and phosphate Phyto also need sulphur to grow

 

[Bubba shrimp]

Apart from light, nitrate and phosphate Phyto also need sulphur to grow

Thanks MB

 

[Dennis Cartier]

Perhaps lookup the phytoplankton fertilizer F2. From the ingredients in that, you should be able to get an idea of what is optimal for phyto plankton growth. You would want to make your own version that does not include all the nutrients that are being provided by the shrimp food. I would expect that would allow you to target the ones that are out of balance, low or non-existent in your water column.

 

[Bubba shrimp]

Great idea. Dont know why I didn't think of that
Thanks this should help narrow down the search for harmony

 

[Bubba shrimp]

Perhaps lookup the phytoplankton fertilizer F2. From the ingredients in that, you should be able to get an idea of what is optimal for phyto plankton growth. You would want to make your own version that does not include all the nutrients that are being provided by the shrimp food. I would expect that would allow you to target the ones that are out of balance, low or non-existent in your water column.

So looking at f2 its primary is nitrate, phosphate both present and Sodium metasilicate (silicate) which I'm waiting to test. The rest is trace metals and vitamins. Which ill investigate further

 

[Subsea]

While I grow phytoplankton using modified F2 formula, I also grow Gracilaria Parvispora, Red Ogo, in a monoculture tank for personnel consumption. On a much smaller scale, I do what you do with your shrimp culture discharge water except it’s from mixed garden reef tanks. To push Red Ogo, I dose ammonia & ChaetoGrow. At present, it doubles its mass every 10 days and I am soon moving monoculture from 20G to 55G tank. If present growth rate continues in 55G tank, I should harvest 20 lbs of seaweed a week. I Intend to send seaweed to a regional agriculture lab and determine dry analysis, then evaluate nutrient feed.

Are you feeding phytoplankton to shrimp larvae? Where are you getting your shrimp larvae from? Ten years ago, I toured a shrimp farm near San Antonia operated by Texas A&M in which production of shrimp equalled 1 lb per cubic foot.

 

[Bubba shrimp]

While I grow phytoplankton using modified F2 formula, I also grow Gracilaria Parvispora, Red Ogo, in a monoculture tank for personnel consumption. On a much smaller scale, I do what you do with your shrimp culture discharge water except it’s from mixed garden reef tanks. To push Red Ogo, I dose ammonia & ChaetoGrow. At present, it doubles its mass every 10 days and I am soon moving monoculture from 20G to 55G tank. If present growth rate continues in 55G tank, I should harvest 20 lbs of seaweed a week. I Intend to send seaweed to a regional agriculture lab and determine dry analysis, then evaluate nutrient feed.

Are you feeding phytoplankton to shrimp larvae? Where are you getting your shrimp larvae from? Ten years ago, I toured a shrimp farm near San Antonia operated by Texas A&M in which production of shrimp equalled 1 lb per cubic foot.

We do feed the larvae phytoplankton with brine shrimp and rotifers.
We currently import from texas. I'm traveling to Belgium at the end of the month for a weeks training on making shrimp feed and how to breed our own king prawns, at an established shrimp farm. For our system green water has all the right mix. I may well try growing seaweed as an extra source of income. My attempts so far with sea lettuce and cleto haven't worked so well. Next phase is to bring a 80ft polytunnel online where I hope the extra sunlight will bring more success.

 

[Subsea]

you may be importing from the the benefactor of research done by Professor Tzachi Samocha at Texas AgriLife Research Mariculture Laboratory at Flour Bluff. When I toured this facility, I meant Doug Ernst, who was VP of R&D at Natural Shrimp outside of San Antoine. Natural Shrimp developed their shrimp larvae. Professor Samacha has retired from academia and is CEO of a consulting company for “shrimp mariculture”.

Good fortune on integrating a sustainable ecosystem whose components feed each other and yield more than one money crop to feed people.

 

[Subsea]

We do feed the larvae phytoplankton with brine shrimp and rotifers.
We currently import from texas. I'm traveling to Belgium at the end of the month for a weeks training on making shrimp feed and how to breed our own king prawns, at an established shrimp farm. For our system green water has all the right mix. I may well try growing seaweed as an extra source of income. My attempts so far with sea lettuce and cleto haven't worked so well. Next phase is to bring a 80ft polytunnel online where I hope the extra sunlight will bring more success.

Red Ogo demands much sunlight, if intensity is insufficient, it will turn pale green. In researching commercial mariculture of seaweeds, air seemed to be the most economical source of circulation using V-Bottom long rectangular tanks, which would do well under a tunnel. In Austin, Tx heat removal was a big energy cost in my 20’ by 40’ hobby greenhouse because I was growing the wrong crop of coral & live rock for distribution to LFS.

 

[Subsea]

Turned off circulation pump to rest the water which aloud the phytoplankton to become dominant. We have 10 4000ltr tanks ras system with settlement Chambers and moving beds for filtration. One large 20000 ltr denitrification tank. That only works when offline from production tanks.
My question really is what are the main elements / components i need to monitor to keep the green water active without crashes.

First,
Your handle for this forum made me chuckle for a long time. Thank you for the humor, wit and marketing genius.

In an earlier profession, I operated municipal wastewater treatment plant as did @Lasse. To reduce nitrate to acceptable levels for discharge into public waters, we used “anarobic digesters” that discharged free nitrogen gas, similar to “facultative bacteria” in an oxidation pond for municipal waste water treatment. With respect to a nutrient feed for phytoplankton, why remove nitrogen in 20,000 liter denitrification tank. Are you reusing water from denitrification tank? Natural Shrimp grew their shrimp in half strength ocean salinity. When shrimp were 100% harvested at the same time and water discharged into flat holding beds where Ulva recycled nutrients from water to be reused in next shrimp cycle. The Ulva was dried up into shrimp food.

In my case, I would have grown some Red Ogo for marketing to restaurants as a niche market.

Red Ogo Seaweed

Red ogo seaweed maintains its bright red color when fresh, but turns a dark green color when cooked. This seaweed offers a nice salty ocean taste with a crispy...

www.specialtyproduce.com

Red Ogo Seaweed

caseagrant.ucsd.edu

 

[Bubba shrimp]

First,
Your handle for this forum made me chuckle for a long time. Thank you for the humor, wit and marketing genius.

In an earlier profession, I operated municipal wastewater treatment plant as did @Lasse. To reduce nitrate to acceptable levels for discharge into public waters, we used “anarobic digesters” that discharged free nitrogen gas, similar to “facultative bacteria” in an oxidation pond for municipal waste water treatment. With respect to a nutrient feed for phytoplankton, why remove nitrogen in 20,000 liter denitrification tank. Are you reusing water from denitrification tank? Natural Shrimp grew their shrimp in half strength ocean salinity. When shrimp were 100% harvested at the same time and water discharged into flat holding beds where Ulva recycled nutrients from water to be reused in next shrimp cycle. The Ulva was dried up into shrimp food.

In my case, I would have grown some Red Ogo for marketing to restaurants as a niche market.

Red Ogo Seaweed

Red ogo seaweed maintains its bright red color when fresh, but turns a dark green color when cooked. This seaweed offers a nice salty ocean taste with a crispy...

www.specialtyproduce.com

Red Ogo Seaweed

caseagrant.ucsd.edu

So its been a case of throwing mud and seeing what sticks as I'm learning everyday. The idea was to try to trickle a flow of water through the anaerobic digester to keep nitrates in tolerance. But the oxegen was too high at 4ppm.
Turning the flow off works to reduce nitrates down to 40ppm then use that water to do water changes as all our saltwater is made diy. The main concern i have is this system doesn't keep the levels low enough in the growout tanks.
With phytoplankton all the system is down to 20ppm while its active. If it crashes the nitrates shoot back up. So my main objective is to co culture zooplankton which the shrimp will utilise for biomass then at harvest I would remove from the system. As with growing superfood seaweed. If I can keep the phytoplankton 365 days I can convert the denitrification tank into breeding or stock tank. So really its only been used as a backup.
All the help and ideas are very much appreciated

 

[Subsea]

Considering that the N ratio of phytoplankton is 16:1 and N ratio of Red Ogo is 30:1, the Ogo may serve nitrate reduction more efficiently.

A generic low cost agriculture lab dry analysis costing $30 yielded these results for Red Ogo:

N at 2.59%
P at 0.082%
K at 13.54%
Ca at 0.555%
Mg at 1.163%
S at 4.81%
Zn at 139ppm
Fe at 107ppm
Mn at 20ppm
Cu at 7.0ppm

Plant Analysis

Are your plants hungry? Plant analysis at Ward Laboratories reveals nutritional deficiencies that negatively impact crop yields. Why do we recommend testing plant tissue? Testing is recommended for two primary reasons: to diagnose visible symptoms of poor plant health. to monitor the plant’s...

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[Subsea]

On a small scale, I grow Tetraselmis phytoplankton that doubles in biomass every 5 days. Red Ogo doubles every 10 days.

ps: The production rates I discribe are not maximum rates, they are easily attained production rates without excessive labor or energy cost. I run both systems with 6500K led par 38 lamps at 16/8 lights on.

 

[Lasse]

In order to run a denitrification tank in constant mode - you need an DOC source (Dissolved Organic Carbon) injected into the inflow to the denitrification tank - or produced in the tank. If injected - ethanol is the most used DOC.You need also a substrate in the tank - nowadays it mostly K1, K3 or K5 media that's normally is in use in nitrification moving bed filters of Kaldnes method. For denitrification - the bed is normally static - if it is moving - it is not moving with help of aeration - instead is moved with help of slowly rotating "propellers". The filter bed should be anaerobic and the flow of water and injected ethanol can be adjusted by an redox controller. IME around minus 150 to minus 200 mV in ORP is optimal. the flow need to be slow.

In my tank - I run a reversed flow under gravel filter (around 20 cm thick) an inject 8 % ethanol in the water stream into the bottom of the filter. The first and the last post in this thread describe the system. Do not bother to read the other 68.

Here you can see my last week and it is still rather stable. The system begin to swing sometimes but after a while it stable up again

This system and a little reversed refugium give a NO3 level between 2-8 ppm NO3.

Sincerely Lasse