[34cygni]

Originally Posted by Quiet_Ivy

Cygni, I've been keeping N and P at a redfield approved ratio since your post. It doesn't seem to make good things happen any faster than randomly upping both.

That's useful information, too.

I'm not a devotee of the Redfield Ratio School of Algae Management, but I thought it might be worth a try because there were a few reports of tanks -- I think yours was one of them -- that went dirty and saw a flush of algae growth before the dinos took over again. My interpretation of this is that the dinos fought back, using their toxins to manage the bacteria population and make the system more hostile to the green algae holobiont, but it was also possible that these systems transiently passed through the "redfield approved ratio" zone as nutrient levels rose, and that was why green algae briefly took off, but then the algae lost a key competitive advantage when the N:P ratio went out of whack.

But apparently not.

Originally Posted by Quiet_Ivy

My dinos were gradually diminishing as N rose, until i hit a 'critical point' and something triggered a mass dino die off. I would sure like to know what.

You and me both.

What took the dinos' place? I'm guessing your tank isn't carpeted with green algae now... Did the dinos go away and leave clean sand?

Originally Posted by Quiet_Ivy

I came home to most of my corals dead and rotting

So, so sorry to hear that not only did your tank crash, but that you were getting a handle on the situation when it fell apart in your absence. I can only imagine how horrible it must have been to come home to that, especially after all that work.

Originally Posted by Quiet_Ivy

My nitrate's now off the scale.

Am I correctly recalling that you're into FW, too? You might dig up an old an airlift and jam it into your sand bed to circulate tank water through the sand. Works better with coarse sand, but that should facilitate denitrification and eventually gas off enough nitrogen to get your NO3 down to FOWLR levels. Should help with dissolved organic N as well as NO3.

I almost suggested this to you last year as a way of trying to mess with the dinos' bacteria farms, but it seemed too simple and too silly to be taken seriously, and what self-respecting reefer would put an airlift pump in a DT? In retrospect, I'm sorry I didn't put it on the table for you to consider.

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Originally Posted by taricha

Over a week ago, when I put the first squirt of dino sand in, 2 days later the dinos had spread slightly

Ye gods!

Originally Posted by taricha

200ml of skimmer "green tea" in to see if that helped. Dinos were dramatically reduced 2 days after that.

Since the dinos spread at first but are now being killed off, that would seem to suggest that whatever's killing them was concentrated in the tea, but absent or too thinly spread to be effective in the tank. After you added an extra dose of dino-killing whatever, these organisms are apparently able to sustain themselves in sufficient numbers to remain effective -- presumably because you're feeding them.

Have you tried making black tea yet?