Corals not Thriving

[iko2thdk]

Hi R2R. My reef aquarium, a RSR350 is a little over one year old. My water parameters seems to be where they should be:
pH 8.13
temp 78.5 F
Alk 10.9
Calcium 400
Mg 1460
phos .04 using Hanna ULR checker
Nitrates under 5.0

Dosing with 2 part using an apex doser and doing water changes of about 20%/month. Water appears crystal clear and the fish have been fine except I lost a flame angel to ich about a month ago. It was removed promptly and all other tank inhabitants have been clean.

My anemone, euphyllia and leather corals have been thriving. Small frags like chalice and plate corals slowly but surely die back from their edges until all their zooxanthellae are gone. I try reef roids, blizzard, mysis, oyster feast, some critters eat, some do not. Running two AI Hydras about 9 hrs a day with mostly blues, violets, very little red and cool white. Ive just sent for to rent a par meter since like many of us, I am home.

Any idea why some of these very attractive corals fail to thrive in what i think is fairly good water quality. There is plenty of flow with 2 vortechs and a tunze.

 

[Euphyllia97]

I think your alkalinity is maybe a bit on the higher end for the small amount of nutrients in your tank. You might try tuning that down to 9 dkh.

 

[bobby.w.hodges]

I agree with high alk being a cause. With a lower nitrate level like you have I would suggest slowly dropping down to around 8 or 8.5 dkh. Might start with just a water change, what salt do you use?

 

[Duffer]

I have low nutrients and keep the alk around 8, corals seem to be happy

 

[sarcophytonIndy]

Lighting? Too little? Too much? Are you starting them in lower lighted areas and moving them up slowly.

 

[bobby.w.hodges]

Let's see some pics to assess the situation

 

[DesertReefT4r]

I agree. Lower the alk, slowly. 10 is high for the low nutrients, shoot for 8.0 ish. Your alk, cal and mag are a bit out of balance. Mag is a bit high and cal is a bit low but there not too bad. Lower your alk dose and increase your cal dose a little and test daily until its dialed back in. 7.8-8.5 alk, 420-450 cal and 1380-1400 mag is a good balance. What salt mix are you using? Was the tank started with dry rock and dry sand or no sand? If so how did you go about cycling and seeding the tank to help get it sps ready? How long to the corals you have issues with last, is it near instant issues or does it take several weeks?

 

[iko2thdk]

I think your alkalinity is maybe a bit on the higher end for the small amount of nutrients in your tank. You might try tuning that down to 9 dkh.

Thanks I am reducing the dosing and will monitor my Alk very carefully

 

[iko2thdk]

I agree. Lower the alk, slowly. 10 is high for the low nutrients, shoot for 8.0 ish. Your alk, cal and mag are a bit out of balance. Mag is a bit high and cal is a bit low but there not too bad. Lower your alk dose and increase your cal dose a little and test daily until its dialed back in. 7.8-8.5 alk, 420-450 cal and 1380-1400 mag is a good balance. What salt mix are you using? Was the tank started with dry rock and dry sand or no sand? If so how did you go about cycling and seeding the tank to help get it sps ready? How long to the corals you have issues with last, is it near instant issues or does it take several weeks?

Thanks. So to lower the alk, maintain same level calcium but reduce the alk dose. I use instant ocean reef crystals I started the tank w dry rock and live sandand cycled the tank w some dr tims and a few fish. the corals last a while but inevitably die back, including a nice hammer which seemed to do well for a while and then just disappeared no brown slime, just gradual steady loss of tissue.

 

[Crustaceon]

Let alk fall on its own to 7.6-8 with that level of nitrates and phosphates. I’d only dose calcium and mag for a week or so. Try not to do too much right now as your corals are already stressed as is.

 

[iko2thdk]

Lighting? Too little? Too much? Are you starting them in lower lighted areas and moving them up slowly.

it does not seem to matter where they are located bottom or higher up, the die back continues...

 

[iko2thdk]

Thanks for all the advice Hope fully some will come back and I will manage my parameters better.

 

[EMeyer]

The purported relationship between nutrients and alk has little evidence or theoretical basis but reducing alk to natural levels (7 to 8) would be a great start.

 

[sarcophytonIndy]

it does not seem to matter where they are located bottom or higher up, the die back continues...

What type of lighting do you have? What photo period are you using?

 

[IslandLifeReef]

@iko2thdk I agree that the Alk is on the higher side, but it is within range. You said you had two AI Hydra's, which ones? If it is the 26HD or 32HD, you may not have enough light.

 

[DesertReefT4r]

Thanks. So to lower the alk, maintain same level calcium but reduce the alk dose. I use instant ocean reef crystals I started the tank w dry rock and live sandand cycled the tank w some dr tims and a few fish. the corals last a while but inevitably die back, including a nice hammer which seemed to do well for a while and then just disappeared no brown slime, just gradual steady loss of tissue.

Yes let the alk drop, lower the dose. You may not even need to be dosing at all if stony coral growth is poor. Let water testing tell you when and what to start dosing. I would switch salts personally, IO is dirty and has high alk. Try either of the HW salts or Fritz. Also your tank just might be mature and stable enough to keep more sensitive corals alive. Try to get some small pieces of live rock or some rock from a mature reef tank that is thriving. This will seed the tank with what dry rock lacks in biodiversity. Bottle bacteria is not the same. Seed the tank, get alk, cal and mag back in balance and let the tank mature.

 

[iko2thdk]

@iko2thdk I agree that the Alk is on the higher side, but it is within range. You said you had two AI Hydra's, which ones? If it is the 26HD or 32HD, you may not have enough light.

They are the Hydra 26's I've ordered a Par meter rental just to see if that's the issue.

 

[IslandLifeReef]

They are the Hydra 26's I've ordered a Par meter rental just to see if that's the issue.

When I added more light to my RSR170, I started having success with SPS. I was running one Hydra 26HD on the BRS AB+ program.

 

[iko2thdk]

Thanks. We will see. Waiting for the meter next week. Should be interesting

 

[DesertReefT4r]

I have 2 Hydra 32s on a 4ft 75g and right now light is not an issue. Running the BRS settings for sps and getting good results. If the tank is packed with sps 2 Hydra 26/32 is not enough, 3-4 is ideal. Not sure on the size of the OP's RSR tank.