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Old 06/19/2016, 06:22 PM   #3789
taricha
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Join Date: Mar 2010
Location: NE Miss
Posts: 535
Follow up on earlier stuff...

Quote:
Originally Posted by taricha View Post
The question seems pretty dang straightforward: What level of single-dose H2O2 kills ostreopsis?
...all doses in ml H2O2 per Liter of tank water.
Concentrations of .5 to .8ml/L caused 100% of dinos to stop moving by 30 min after, and some lost theca.
But next day, many of the dinos had recovered in each beaker.

next the one question becomes 2: what peroxide level to kill ostis in the dark, and what level kills them in the light?

...blah blah stuff about studies in light vs dark peroxide application...

side note: I guess, that any application of peroxide to kill photosynthetic stuff should be done in bright light to reduce the amount of H2O2 required.
So I've done paired light/dark tests, and checked the ostis for any movement the day after adding different amounts of H2O2 (in ml/L).
No = Not a single osti moving
Yes = Somewhere in sample there was an osti still moving
H2O2 - light - dark
1.6 - Yes - Yes
1.8 - Yes - Yes
2.0 - No - No
2.2 - No - No
2.4 - No - No

I'll do a few more sets to confirm numbers for single dose before moving to gradual doses.

What I don't get is that I've seen no difference in any test so far between peroxide applied in the light (beaker lit by sump lights that grow chaeto) and peroxide applied in the dark (inside a cabinet).
There are some good reasons to think that light would make peroxide more effective, and maybe even some arguments that darkness could be better for peroxide use on ostis - peroxide persists longer in the dark, and perhaps more of it can get into the inside of the cell before reacting.

But I honestly can't figure how light/dark has no effect that I've been able to see so far.


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