Green Water

I've used Daphnia, worked well, took awhile for the number to get high enough.

Problem:
Fish like to eat them. Rotifers are not even close to being as effective, you might get a predatory Rotifer that eats the other rotifiers that are herbivores.
Daphia interfere with Rotifiers when both are present but Daphnia do not "prey" on them just mangle them as the Daphnia feed.

Daphia are much more efficient.
But the rotifiers generally are too small to be eaten by many fish.

It takes longer than Diatom or UV methods but is the natural method.
Works well on mild cases or lower lighting.
PC lighting has awful times with GW.

You'll never starve the GW.
Once induced, it's there to stay unless you remove it all.

GW is not Volvox nor Egulena. GW is much smaller, roughly 2-3 microns across and very fast. I've enevr found Egulena in any aquarium samples ever. The group is completely asexual.

When I get back I'm going to run some over a EMS to get a good look. Light microscpoes are insufficent.

Regards,
Tom Barr
 
Anyone who can culture infusoria is culturing all kinds of critters that eat green water. ("Well I'm not going to culture infusoria in my tanks, wetman!") My own experience is only with planted tanks and soft water-- fo forty years.

How small? Well, I have a cylindrical salad bowl, maybe a gallon and a half, packed with plantlets and cuttings, with a single male Paradisefish, and enough gravel scarcely to cover the bottom. The water's always crystal clear, but a test tube held up in the window and inspected with a 10x loupe is swarming.

Any predatory rotifers are kept in check by the availability of their prey. Populations naturally settle into ratios of predator to prey that are astonishingly similar whether it's lions/antelope or rotifers/ciliates. The predatory rotifers don't just gobble up all the prey and then... what? Only humans do that.

After medicating for an Ich outbreak, I've sometimes decimated the plankton, and I get vaguely cloudy water sometimes. Then it dissipates (but not by magic!).

You can control the green in the meadow with herbicide, with a blowtorch-- or with a cow.

I'm not advocating ideologically "natural" aquaria, BTW: I use carbon and polyfilter and water changes etc etc like everyone else.
 
When I had GW bad , I did 50% waterchange +blackout+50% waterchange + diatom filtering for a week off/on +UV sterilizing for a week = clear tank (125G)

I am intrigued with the use of daphnia.

If I had the same tank what would I do?

Net daphnia in a pond and introduce them after getting all the fish out? If I did ; how long would it take a couple of dozen daphnia to multply and knock out the GW? and would I just be able to introduce fish afterwards to consume the daphnia? Is there a better micro organizm?
 
It's a whole community, not just one organism, inxs. Don't you know anyone who has a clear clean planted tank and would let you siphon off a gallon or two, with plenty of detritus from the substrate? That would cure green water in ten days.

What's in it? bacteria, cyanobacteria, diatoms, algae, euglenoids --being eaten by ciliates, some flagellates, amoebas, hydra, rotifers, microturbellaria, nematodes, aelosomatids, naidids, rotifers, gastrotrichs, plus all the water mites, a few springtails and the microcrustaceans, especially copepods.

The problem with Daphnia is that they're so big and noticeable the fish decimate them.
 
Well, my experience with green water in a 45g start-up tank stocked with zooplankton was a 6 week affair. The daphnia population blossomed all right, but so did the cyclopoid and hydra population, which kept the daphnia population in check. Some of the first ciliate grazers to bloom were the larger scoop-shaped ciliates, like Lembadion. Man, I sure miss that bloom, it was a lot of fun. :D

Inxs, if you want to play around with daphnia, make sure it’s a pure culture. Collecting wild daphnia without screening the catch is a good way to introduce copepod raptors into the tank, and they’ll decimate your daphnia population.

As for the other herbivores in a tank, IME the collective zooplankton only shorten a water bloom, but won’t prevent one. There’s always a lag period between between the bloom trigger and grazer population growth. I have this 29g that I use to sort out my collecting forays and it blooms religously every 2 months when I add aged tap water to it.

IMHO, daphnia aren’t worth the extra effort with diatom, UV filters, and tank blackouts as the other options. Unless you like to experiment. :D


Tom
 
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That's my point Tom, i'd love to go the way of Wetman and Plantbrain if I could but practicality seems to point me in the way of UV and Diatom hence the question about what is to me unknown : biocontrol.

I'd love to be able to do it if there is a way to do it practically.
 
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