Help needed

[Aridala]

I have been keeping saltwater fish for about 30 years now, and a couple of months ago decided to try my hand at corals. I have a 120 gallons tank that has been established for 7 years now. I also have quite a bit of live rock. I decided to go with the Aquaillumination HD32 lights, of which I have three set for the Saxby settings mounted about 8 inches above the water. I have three bubble tip anemones which seem to be doing very well, a couple of emerald crabs, an arrow crab, two fire gobies, two tomato clowns, two occellaris clowns, three skunk clowns, a sailfin tang, a bi color blenny, a six line wrasse and a hawkfish.
My issue is I can't seem to keep the corals alive. I have two zoa frags, a toadstool, a green star polyp frag and a purple hair mushroom, and two that I don't remember what they were, but tey looed awesome. None of them seem to be doing well. I also have started to notice a brown stringy algae that is forming on the back glass, the rocks and on the toadstool.
For equipment, I have a Fluval FX6 canister filter, a HOB refugium with algae to absorb phosphates, and two Jabao wavemaker powerheads. I also have a doser that delivers 20ml of reef food a day.

Chemistry is as follows...
Salinity 1.025
Temp: 79.2
Ca: 420
KH: 9
Mg: 1400
Silicates: 0
Phosphate .03
Ammonia: 0
Nitrite:0
Nitrate:0
pH: 8.2

Dropbox link to pictures of corals and brown algae: https://www.dropbox.com/sh/1icz2n32g4z4adg/AAAw7dNKY4Vxltb-zcfqLy6Na?dl=0


Any ideas what I should do next? I have no clue what to do now.

 

[Koconnor15]

I would bring up the CA to around 450. It looks like you have some LPS and they're going to consume your CA to build skeletons. Scale back on the reef food. I'm not sure what kind you're using but you have a small amount of coral for that much excess nutrients. I'm not sure what the white stringy stuff is but the brown is most likely excess nutrients from the Reef Food and/or your coral had something on it. Even dipping doesn't always get everything.

 

[MaxTremors]

Your calcium is fine at 420 (even 400 is fine), so long as it’s stable. The nitrates being 0 is not good, corals need some nitrates, you also run the risk of dinoflagellates. Try to get them up to somewhere between 3 and 15ppm. Since you’ve had the tank set up for 7 years as a FOWLR, have you ever dosed any medications (specifically copper based)? I would think you probably need more flow, two Jebao wavemakers for a 120 gallon isn’t much. How quickly are the corals dying? Where are you placing them, and what settings/intensity do you have your lights at? Are you using RODI for top-off/water changes? I would also stop the reef food, or cut it back to once every week or two.

 

[NowGlazeIT]

Double check the lens of those lights, they have a history of melting from the UV diodes, this will also drop your par some

 

[Aridala]

Your calcium is fine at 420 (even 400 is fine), so long as it’s stable. The nitrates being 0 is not good, corals need some nitrates, you also run the risk of dinoflagellates. Try to get them up to somewhere between 3 and 15ppm. Since you’ve had the tank set up for 7 years as a FOWLR, have you ever dosed any medications (specifically copper based)? I would think you probably need more flow, two Jebao wavemakers for a 120 gallon isn’t much. How quickly are the corals dying? Where are you placing them, and what settings/intensity do you have your lights at? Are you using RODI for top-off/water changes? I would also stop the reef food, or cut it back to once every week or two.

I have never dosed anything with copper. I have always had some sort of invertebrates, most commonly cleaner shrimp, so I never used copper. As for the flow, I actually thought the two might be too much.
The corals do not die quickly. I actually think they can all survive if I find out what I'm doing wrong. I unplugged the doser to start with. Yes, I use RODI to top off, and I get the Imaginarium Ocean water from my local Petco for 20% water changes monthly.

 

[MaxTremors]

I have never dosed anything with copper. I have always had some sort of invertebrates, most commonly cleaner shrimp, so I never used copper. As for the flow, I actually thought the two might be too much.
The corals do not die quickly. I actually think they can all survive if I find out what I'm doing wrong. I unplugged the doser to start with. Yes, I use RODI to top off, and I get the Imaginarium Ocean water from my local Petco for 20% water changes monthly.

I’m not seeing anything that really stands out as the cause. Are you running the David Saxby at full intensity? If so, and if the corals are placed too high in the tank, they could be getting burnt by the light. You might try getting an ICP test done to see if there’s something we can’t test for or that we might be overlooking.

 

[Aridala]

Follow up....
I turned off the doser totally and the brown stuff cleared up within a week. I set the lights on acclimate mode, and as of today, the corals are doing fantastic, even two that I thought were dead have made a comeback (most notably my Toadstool).
However, my anemones aren't doing so well, but that is the subject of another thread I started a few minutes ago.

Thank you for the responses, they were extremely helpful.