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Ulva growth subsided

Discussion in 'General Discussion' started by atoll, Oct 10, 2017.

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  1. atoll

    atoll Member

    Over the last couple of weeks, the Ulva intestinalis that previously grew at an incredible speed has subsided greatly to the extent it went from around a 410gramm harvest to just a couple of grammes. What I can only describe as a compact dark spongy moss type algae have taken over where the once Ulva proliferated. I have just completed some tests, My NO3 is between 0.05ppm and 1ppm, my PO4 is 0.015ppm. Once in a while I dose a little iodine and have recently been adding a small amount of iron twice a week.All corals are as well looking as they have ever been with vibrant colours. For example, a Forest fire which had lost it's colourful yellowish tips has come back wonderfully and all SPS corals are growing at a fast rate. Are my nutrients now too low as when I started with my Atlantis 2 scrubber my NO3 was 20ppm and my PO4 was 0.04ppm?
    I have just cleaned off the screen (both sides) using an old credit card scraping right back to the screen and rinsed under tap water, then reseeded with a little Ulva so will see what grows back the strongest.
    Pic's of both sides of the screen.

    20171010_134856 (1).jpg

    rfbrowne likes this.
  2. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Looks like tank chemistry changed in favor of the GHA that is growing now. Either that, or the GHA is managing to either outcompete the Ulva or it is chemically inhibiting it in some way.

    It does go to show - algae's gonna do what it wants, you can't force it!

    The algae you are growing looks like a patchwork of many different types of algae actually.
    atoll likes this.
  3. atoll

    atoll Member

    Thanks, Bud, Yeah there are at least 5 possibly more types of algae growing. With regards to GHA well, the H bit is largely missing from what is growing as there is little to no hair algae growing.
    Seeing as I have scrapped the screen back to the bone and reseeded with what Ulva I had left it will be interesting to see what grows back.
  4. atoll

    atoll Member

    Pic of all the very dark algae I have scrapped off the screen.

  5. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    I'll be interested to see if you can indeed force it to do what you want :)
  6. atoll

    atoll Member

    A guy replied to a post I put up another forum reported his algae scrubber went similar, he removed all algae by scraping it off and reseeded with Ulva and the Ulva took off again so we shall see. I will report back in a week or so on how it goes.
  7. TbyZ

    TbyZ Member

    Why do you favour the ulva over the naturally occuring gha ?
  8. atoll

    atoll Member

    It grows at a phenomenal rate, brought my NO3 down from 20ppm to 5ppm in less than a month, I can feed it to most of my fish, even my cleaner wrasse eats it as well as my clowns, blennies, damsels and angels. I did a lot of research on Ulva intestinalis and it was reported it grows in polluted water and has an incredible uptake of nutrients.
  9. TbyZ

    TbyZ Member

    Sounds great for cleaning up a neglected aquarium but maybe gha is better for keeping an aquarium clean & stable.
    One thing is, if ulva grows so aggressively that means more maintenance.
    It seems like the ulva' s subsided now because its no longer needed .
    Just IMO.
  10. atoll

    atoll Member

    I know a number ofreefers with excellent aquariums with low nutrients growing Ulva in an ATS certainly not neglected. The Ulva when growing well needs harvesting once a week there is just so much more of it than GAH usually.


  11. TbyZ

    TbyZ Member

    Yeh, neglected was the wrong word. I meant it seems to need & do best in high nutrient environments.
    Anyway good luck with it
  12. Southpaw007

    Southpaw007 New Member


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  13. atoll

    atoll Member

    Just took a few pic's of the screen. This growth is after 7 days and as you can see there is still not as much Ilva as I had before with the tick dark moss type still be more in abundance. I have 2 choices, I can completely scrape the screen and dip it in bleach to remove all traces of algae or simply continue to harvest whatever grows as before.



  14. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    I still say that you can't (or more accurately, it's very difficult to) force a specific type of algae to grow over another. I really think that your initial seeding of the screen worked because there was nothing else on the screen, so it took off right away.

    As the screen matured, another type of algae found the conditions to it's advantage and it got a foothold.

    Your tank conditions seem to be preferential to the second type of growth. At least, that's the case right now.
  15. atoll

    atoll Member

    Yes, I understand but all my 36 years in this hobby I have pushed the boundaries one way or another and still do. I understand exactly what you are saying but the little voice in my head keeps say go for it so I have. I have scraped the screen clean, put the Ulva to one side in some salt water and put the screen in a strong bleach solution which I will leave for an hour or so then rinse well before reseeding with Ulva.
    Now if the screen eventually goes back to the way it was then fine I will leave it like that and just clean as I usually do. What I expect is the Ulva will grow well as it did when I first set my ATS running but we shall see and I will report back periodically on progress or lack of it.
    Turbo likes this.

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