Well guys, latest victim here.
Been looking over this thread for a couple days. I believe to have an Amphidinium outbreak. The photos above were taken this morning when I turned on the lights prior to the evening. The brown stuff on the substrate gets more intense throughout the day, and then fades with lights out. I also note that in the areas where direct light does not hit the substrate there are no noticeable brown patches (although assume it's present). No bubbles, and it's not on the rock.
Tank History
Reefer 350, started in late July with TBS rock and Arag-Alive Special Grade substrate. No fish present, 2 frags, 1 wall hammer, 2 BTN, one pistol shrimp, one peppermint shrimp, and one cleaner shrimp, few turbos, 2 fighting conchs.
Salt to date was HW Marinemix. Recently switched to Red Sea (regular) because it was dirt cheap locally. RO is a 6 stage BRS (2 carbon and 2 DI). Lights are 2 Kessil A360WE, max intensity is 45% and max color is 30%, ramp up over 8 hours. Apex controller, RD3 50w pump, BK mini 160 skimmer. Dosing 2 part till recently (more later). Water change schedule has been ~ 10 gallons a week (more later).
There was no cycle with the TBS rock, but I did have die off. NO3 hit 50 (salifert) or so, PO4 hit 1ppm (hanna), currently I have been running some GFO to get the PO4 down to about .07 and water changes to get the NO3 down to about 20ppm. I had a patch of GHA on the rock which are now gone.
I initially thought the dino was diatoms, so I added the 2nd DI to the RO and changed out the first when I initially started seeing the brown stuff. At about this time I started the GFO (it removes silicates too).
I currently am skimming pretty wet. I empty the cup every two days and change socks about every 3-4 days.
The brown stuff on the substrate has been there for about 3 weeks, I tried lights out for three days and it went away for about 2 days (during this period I added the nems).
Kh is 8.16 or better (would dose to 8.3 if at 8.16) and Ca 420-445 and Mg 1325-1400.
Rock looks great. Target feed shrimp with some LRS chunks about 2x week.
I have a Potters angel and Yellow shrimp goby in QT right now, they have been there for 5 weeks and will stay there till I get rid of the brown stuff.
Recent Variances
My Ph was pretty much 7.9-8.1 depending on the light cycle, in the past two weeks it has went into a range of about 7.75-7.85. More brown stuff appeared. My conchs have been below the substrate I assume getting their fill of the dino. I will also note I have a number of the red worms as observed by FishKeeper82.
I recently discontinued the 2 part and started dripping Kalk at night to combat the low Ph, hopefully help with PO4 and to keep my alk in check. My Ph has improved some it's up to 8.02 yesterday with a low of 7.8 in 24 hours. My Kh is at 8.48. Was doing 1/4 tsp in a gallon of water, upping this today to 1/2 tsp in a gallon, would like to see the Kh around 9.
SWAG
My Ph dropped bad as the Amphidinium got thicker. Thinking CO2 is doing something and hoping the Kalk will lower the CO2 and possibly fix this (yea right).
I have not done a water change this week.
Game Plan
I discontinued the GFO yesterday...don't know if that is making Fe available to the Amphidinium. Will continue Kalk, doubt it will hurt.
Thinking of going for no water changes and see if it chokes itself out naturally. Also thinking of vacuuming the substrate and doing a huge water change and continuing with the no water changes to see if this helps remove the population. I don't think this will help and I will be back were I am in 2 weeks.
-Might add some Chaeto to the sump.
-Was thinking Peroxide, but don't know how that will work with the Nems and shrimp.
-Ordered some Dino-x to have on hand.
-Worse case scenario, ditch the substrate.
-thinking of ordering about 40 cerith snails to churn substrate and eat the Amphidinium.
I would appreciate anyones thoughts and ideas on how to approach this. I have reached out to a couple others on the board with this and they did not really know how they got rid of it...which leads me to believe it choked itself out on it's own.
