Phytoplankton

[lx5litre]

I am in the midst of making my first batch of phytoplankton. It has been 4 days and I see things are moving along pretty well, I think. But how do I know when it is ready? Is there a test or just when it turns greener??
Thks,

[BlueAbyss]

You could look at it under a microscope, do a quick survey of the species floating around in there and then decide if it's suitable. This will require a microscope, some time, a good reference (with pictures!) of phytoplankton, and a whole lotta geekiness. My sort of thing

Barring that (though a microscope would still be handy) I would say when it's a nice bright green and opaque, it's ready.

[lx5litre]

I thought the darker the green, the better. I read one site and the guy was doing it for around 3 weeks and he didn't split the colony yet and then I read another one that said 7 days.. so I guess a brighter green.

[Kabong]

The method I found to gage the "thickness" of my phyto is to.
Get a small container place a bread tie/clip (a red one works best) in the bottom.
Add phyto by the milliliter until you can no longer see the clip.

Of course you really need a true source to get a comparison measurement from.
I originally used some DT's to get the initial measurement.
Then grew my own and compared the difference in mm between the two.
The best batch I ever had was approx 75% concentration of DT's

[BlueAbyss]

If you let the culture go too long it will contain a lot of dead stuff and could potentially become contaminated with bad DOCs from the breakdown of said dead stuff. Not something you want to add in quantity to a tank full of expensive corals. That said, I'm sure a week is pretty safe, but its something to keep in mind.

[hillbillyreefer]

I leave mine brew until I can't see through the 2 litre bottle 2-3 weeks. Then shut off the air and let it sit in a cool place and settle for a couple days. Pour off the thin stuff on top and use it to restart the next batch and put the concentrated stuff in the fridge for the tank. If you really care florida aquafarms sells some sort of meter to give you a density, I think it is a colorometer(or something like that). They are around $10 bucks so should only cost around $100 to have it at your door,lol.

[Funky_Fish14]

You know, it really doesnt matter when its 'ready'. You CAN start using it at any time. Phytoplankton naturally occurs/grows in your aquarium, and even if you are dosing a lower density, it still benefits your aquarium. You could also just add more. You can keep a couple cultures going and restart each one every few weeks, just to make sure you dont end up with a crash, but otherwise, you can really use it at any time. And if you mean for storage, who says you have to store a month's worth? Store a few weeks worth, grow some more for a week or two, and then store more.