Resources on the Diatom Problem & Evaluation of the Techniques (including filters & UV light) for Mitigating it

[stephen_lowery]

Hi, everyone. I'm looking into techniques to mitigate the diatom problem in kelp hatcheries. First thank you to the GreenWave team for what you've/they've already compiled (which I've read & will reread shortly). If anyone else happens to have some good resources on hand or experience with techniques (including not just the conventional addition of germanium dioxide but also filters & UV light) that did or did not work, please let me know.
Also, if there are any kelp hatchery managers reading this, do you all have any analyses on how much time, money & resources are spent trying to control this problem, and how much juvenile kelp is lost as a result of not being able to control it well?
Thanks for any help and regards.

[toby_sheppardbloch]

@stephen_lowery Rigorous water treatment and filtration before it enters the cultivation tanks is an important control measure. In the GreenWave nursery we utilize a protein skimmer with ozone injection, UV, and mechanical filtration down to .2 microns. We also use UV units in the tank circulation loops. Geranium Dioxide is effective to control diatoms but also slows the growth of sporophytes so should be used sparingly.

[stephen_lowery]

@toby_sheppardbloch thanks for the fast response.
I don't suppose you could please tell me which specific components (company, product name, ID) you all are using, and which you think are reputable in general including "best in class", for the following hatchery items:
1.      35 Micron Mesh
2.      Cartridge Filters (20-0.2 microns)
3.      Sand Filter
4.      UV Filter (you've mentioned "UV units in the tank circulation loops")
5.      Germanium dioxide (I'm unclear on the requirements for the processing purity & sourcing; I'm finding "electronics grade" sources, but they appear to be unnecessarily pure & expensive for this application. Also I'm not sure what food & safety regulations would apply...)
and
6.    Hollow fiber filter?
I've pulled these items from the Small Hatchery Budget document, but I couldn't find any of the specific brands (sometimes components will have the same general name but might have very different functions and/or features that prevent/allow them from being used in a particular application).
Thanks for your work so far and thanks for any help on this.

[kendall_barbery]

@Michelle_stephens could you weigh in on Stephen's comment above?

[toby_sheppardbloch]

@stephen_lowery
Here's what our current system is using:

1. 25 micron bag filter (https://www.supplyhouse.com/sh/control/reviewproduct/~product_ID=155390-03?pr_page_id_variant=155390-03&pr_source=email&pr_page_id=155390-03&pr_email_collection=toby%40greenwave.org)
2. 5 Micron cartridge filter (https://pentairaes.com/filter-cartridge-5-micron-20.html)
3. Ozone injected into protein skimmer (https://www.aquacave.com/rk2-xflo-6-3-5-protein-fractionator-venturi-driven-no-pump.html)
4. After the protein skimming completes, we transfer through a UV sterilizer (https://www.aquacave.com/aqua-uv-twist-57-watt-uv-sterilizer-black.html)
5. Then through 1, .35 and .2 micron cartridge filters ( https://www.wecofilters.com/p2mplwct2510.html)

We aren't using hollow fiber filters any longer. Our water is sourced from a facility where it passes through a sand filter.
Germanium dioxide isn't great for the kelp, so best to use sparingly. Highly filtered water mitigates the need for it, although there can still be diatoms from the spore extraction process so it may be needed during the first week or two.

[stephen_lowery]

@toby_sheppardbloch, thanks for the list Toby.

[stephen_lowery]

@toby_sheppardbloch thanks for the fast response.
I don't suppose you could please tell me which specific components (company, product name, ID) you all are using, and which you think are reputable in general including "best in class", for the following hatchery items:
1.      35 Micron Mesh
2.      Cartridge Filters (20-0.2 microns)
3.      Sand Filter
4.      UV Filter (you've mentioned "UV units in the tank circulation loops")
5.      Germanium dioxide (I'm unclear on the requirements for the processing purity & sourcing; I'm finding "electronics grade" sources, but they appear to be unnecessarily pure & expensive for this application. Also I'm not sure what food & safety regulations would apply...)
and
6.    Hollow fiber filter?
I've pulled these items from the Small Hatchery Budget document, but I couldn't find any of the specific brands (sometimes components will have the same general name but might have very different functions and/or features that prevent/allow them from being used in a particular application).
Thanks for your work so far and thanks for any help on this.

[kendall_barbery]

@Michelle_stephens could you weigh in on Stephen's comment above?

[toby_sheppardbloch]

@stephen_lowery
Here's what our current system is using:

1. 25 micron bag filter (https://www.supplyhouse.com/sh/control/reviewproduct/~product_ID=155390-03?pr_page_id_variant=155390-03&pr_source=email&pr_page_id=155390-03&pr_email_collection=toby%40greenwave.org)
2. 5 Micron cartridge filter (https://pentairaes.com/filter-cartridge-5-micron-20.html)
3. Ozone injected into protein skimmer (https://www.aquacave.com/rk2-xflo-6-3-5-protein-fractionator-venturi-driven-no-pump.html)
4. After the protein skimming completes, we transfer through a UV sterilizer (https://www.aquacave.com/aqua-uv-twist-57-watt-uv-sterilizer-black.html)
5. Then through 1, .35 and .2 micron cartridge filters ( https://www.wecofilters.com/p2mplwct2510.html)

We aren't using hollow fiber filters any longer. Our water is sourced from a facility where it passes through a sand filter.
Germanium dioxide isn't great for the kelp, so best to use sparingly. Highly filtered water mitigates the need for it, although there can still be diatoms from the spore extraction process so it may be needed during the first week or two.

[stephen_lowery]

@toby_sheppardbloch, thanks for the list Toby.