Beautiful, dreaded diatoms

[pwnell]

These diatoms are part of the reason I decided to tear down my reef aquarium. I have been battling them since May last year, and have not succeeded in eradicating them. They are beautiful though, however when in great numbers they detract from the beauty of a reef aquarium.

My best guess at this time is that the new LED technology I decided to use for illumination had just the right spectrum of blue light to fuel their growth. My reasoning is that I never had these diatoms in my previous tanks which used a combination of Metal Halide and T5 fluorescent lights. This is the first tank to use a pure LED based light source. I know the blue component is very strong in this particular model. Also, judging from the very strong autofluorescence under Blue/UV excitation, I conclude that they effectively consume blue light and that that is fuelling their growth.


20140908-DSLR_IMG_0058-Edit.jpg by pwnell, on Flickr
Reef tank diatoms, 20x*1.25, DIC, HF B


20140908-DSLR_IMG_0083-Edit.jpg by pwnell, on Flickr
Reef tank diatoms, 20x*1.25, FLUO-C6.1, HF C


20140908-DSLR_IMG_0169-Edit.jpg by pwnell, on Flickr
Reef tank diatoms, 40x*1.25, FLUO-C6.1, HF C


Diatoms by pwnell, on Flickr
Reef tank diatoms, 60x/1.2*1.25, FLUO-C6.1


20140908-DSLR_IMG_0314-Edit.jpg by pwnell, on Flickr
Reef tank diatoms, 60x/1.2*1.25, FLUO-C6.1, HF B+C


20140908-DSLR_IMG_0347-Edit.jpg by pwnell, on Flickr
Reef tank diatoms, 60x/1.2*1.25, FLUO-C6.1, HF B

[Jacek]

Beautiful

[Olympusman]

Love the first one.

Mike

[vasselle]

Very nice

[RogelioMoreno]

Beautiful set and specimen.

Rogelio

[RogelioMoreno]

Beautiful set and specimen.

Rogelio

[Marek Mis]

Waldo, I could say almost the same about your photographs as you told about mine - they are very characteristic, in your style . Very nice !
I especially love the fifth one which is very graphic.

Marek

[pwnell]

Thank you for your kind words.

[discomorphella]

Spectacular and beautiful shots. Some of the nicest autofluorescence shots I've seen in fact.
Now, a nonmicroscopical question. I was JUST ABOUT (this weekend perhaps) to remove 450W of VHO fluorescent lighting from my reef tank and replace it with, wait for it....2 large multispectral LED arrays. They do have separate controls for blue/actinic and white light, but now...which model LED source(s) did you use if I may ask? Although I don't have a lot of organic burden and my NO3 and PO4 are almost too low to measure I am now wary of switching. But I am tired of changing lamps. and the tank could use more light... perhaps I should add some Ge source to knock the diatoms back a bit. There are quite a few things in my tank that like to eat diatoms so maybe I'll be ok.

David

[pwnell]

Spectacular and beautiful shots. Some of the nicest autofluorescence shots I've seen in fact.
Now, a nonmicroscopical question. I was JUST ABOUT (this weekend perhaps) to remove 450W of VHO fluorescent lighting from my reef tank and replace it with, wait for it....2 large multispectral LED arrays. They do have separate controls for blue/actinic and white light, but now...which model LED source(s) did you use if I may ask? Although I don't have a lot of organic burden and my NO3 and PO4 are almost too low to measure I am now wary of switching. But I am tired of changing lamps. and the tank could use more light... perhaps I should add some Ge source to knock the diatoms back a bit. There are quite a few things in my tank that like to eat diatoms so maybe I'll be ok.

David

Thanks for your kind comment. So here are my investigations and what I tried so far.

- Under T5 and MH illumination I never had diatom issues (i.e. large blooms).

- My 60g tank had been up for 1 year and I experienced these blooms for the last 9 months of that period.

- This tank was different only in two ways from my previous tanks - I used LED illumination as opposed to T5 / MH, and I did not have a reverse lit refugium with macro algae.

- My P measured < 0.008 ppm
- NO2- was always unmeasurable using low range Salifert test kits
- NO3- was always below 1ppm
- Si was undetectable
- pH was between 8.2 and 8.5
- Alk was > 7dKH
- Ca was > 410ppm
- Mg was 1350 ppm

I dosed kalkwasser through my ATO unit to maintain alkalinity and Calcium levels.

I fiddled with the spectrum of my LED unit - I have this unit:

http://giesemann.de/594,1,,.html

Giesemann Futura S

As you can see, I had blue, purple, white, green and red LEDs. I could mix them to my liking and adjust the curve for ramping up / down the light to simulate dawn / dusk. No matter how I changed the light spectrum - the diatoms never went away. That said, I did not drop the blue out completely as I needed that to maintain a pleasing look.

I ran GAC and PO4 remover in fluidised canisters.

My main display tank had a semi deep sand bed and 65lbs of live rock - so I had no issues with nitrification and denitrification.

Feeding regime was tight - I only fed what my inhabitants could eat in a couple of minutes.

I had one medium yellow tang, two banggai cardinals and one small green mandarin. The rest were inverts and coral - so the bioload was very small.

The TDS of my RO/DI water is < 0.5ppm. I even replaced all the cartridges and membranes to ensure it was not bad RO/DI water.

Salt mix is D-Deltec H2O - I used that successfully on two other tanks.

Water changes were monthly 40% - which is also in line with my previous tanks and worked well before.

So yeah, I am 70% confident it is the LED source. Especially since my LFS told me they have had their own issues with diatom blooms recently after switching their main display tank to LED, and so too some of their clients.

This is not scientific proof, but enough to make me think twice before buying LEDs again, at least until they sort out the spectral issues if that is indeed the cause.

[fpelectronica]

Very nice