Corals won't open

[Reef Doctor]

My Dad is a beginning reefer. He has a 75 gallon tank a little over a year old. He just added his first two corals a couple weeks ago. They don't seem to open. He couldn't remember what kind they are. I live in a different state, so I can't go check them out to verify the variety (my Dad also can't take good pictures.)

He runs a dimmable ATI Sunpower 6 bulb T5 light system. I didn't have time to verify all his parameters but he did recall the following:

Calcium 350
Magnesium 1450
Alk (a little low) 3-4 meq/L
pH was low
Nitrates (he didn't tell me, but he usually runs 8-12

I basically thought it could be two things: 1. He was running the lights too long on full power (possibly 8-10hrs); 2. His alk/pH was too low for the corals.

He has a hard time maintaining his alk and pH up. He doses alk booster constantly. I think it may have to do with his sump being in a closed pantry closet and there may not be enough airflow to move the CO2, (I told him to get a fan.) He has one powerhead in the display tank, and I think could probably use another.

Let me know what you think, and if I am way off base in my thought process.

[ajcanale]

It could be one of many many things, or a combination. I'd lean towards saying nutrient (phos/nitrate) related or lack of acclimating, as those seem to be pretty common for upsetting corals. I doubt it's the lights but it is a possibility I suppose.

Dosing alk constantly concerns me though. I'm no chem. expert but regardless of low CO2 and pH how is the alk being used up? unless it is precipitating. Could a faulty alk test be the issue here?

[RocketEngineer]

What is his specific gravity? If salinity is off, corals react.

[Kyle918]

What is his specific gravity? If salinity is off, corals react.

I agree. Salinity and temperature should be tested. Also, his calcium levels are low for corals.

[Reef Doctor]

Salinity is usually 1.024-1.025. It could be temp. He had a heater die prior to getting the corals, and I assume he has a new one functioning well. He usually keeps his temp around 78 degrees. I've heard of some people keeping their temps more around 82 degrees. I'm not sure what the consensus is?

With regards to Alk, I've never heard of Alk precipitating, only calcium, which based on his ratios, he could stand to raise his calcium levels quite a bit before it would precipitate. Since the tank was first set up, he has consistently had low alk/pH. I'm not sure if the RO/DI water he gets from his house is naturally acidic. The only things using calcium in the tank is the few hermit, snail invertebrates and live rock. He literally only has two small new coral frags in the tank, along with his fish.

[GregPoutine]

get a pH buffer and make sure he only adds what is recommended i think 1 tsp/ 30 gal. read the directions.

good luck!

[Jpruitt546]

PHbuffer is only a temporary fix to an ongoing problem elsewhere. In regards to PH and ALK i would also check magnesium as it to can affect how these levels are mainatined. I would advise run lights for 6 to 8 hours starting off and check all levels again. If the corals start to open then gradually extend the light cycle up slowing until you reach your desired length.

[ajcanale]

PHbuffer is only a temporary fix to an ongoing problem elsewhere. In regards to PH and ALK i would also check magnesium as it to can affect how these levels are mainatined. I would advise run lights for 6 to 8 hours starting off and check all levels again. If the corals start to open then gradually extend the light cycle up slowing until you reach your desired length.


He posted magnesium reading @ 1450...

A little high, but something doesnt add up here. I don't understand why alk is being constantly dosed if there is little to no demand.

[Jpruitt546]

Sorry i missed the magnesium reading. What is the ph reading of the new water going into the tank from water changes. Also whats the precentage of water changes he is doing. Weekly or never?

[Reef Doctor]

I'll have to check with him what his RO/DI pH level is. I know he either does weekly or monthly water changes, but I'm not sure the percentage.

If he had his sump in an enclosed area with little ventilation, would that be enough for CO2 buildup, thus lowering the pH. I've heard if there is not enough ventilation, or surface water turbulence, it can lower pH?

Also, is 78 degrees an OK temp, or should it be higher?

[sponger0]

A full list of parameters is needed. And accurate numbers...not something like and if he is dosing....what is his dosing regimen? What is he dosing?

Another thing is when did T5s become dimmable? Ive never heard of that.

Also what type of corals? That can make a difference.

So give us:

Temp swings from highest to lowest through the day
Salinity (hydrometer or refectometer measured)
Alk and how much its swings and if its being dosed for
Mag
Calc
Nitrate
Nitrite
Ammonia
Phosphates
Lighting schedule


Oh and I wouldnt worry about pH unless its fish or a last resort. Ive never tested for pH in almost 2 years now.

[chrisfont23]

Also depends on the corals. If they are LPS and being blasted with flow, don't expect them to open. If I hit my blasto with any type of regular flow, it closes up. This is not easy w/o desc or pics :)

[Reef Doctor]

I know this is a hard thread without full information, but I live out of state and don't have access to his tank. I talked to my Dad on the phone and he informed me his two new coral frags are now dead. He wasn't sure what kinds they were (FYI, I don't condone purchasing something I know nothing about). He said he just asked the LFS what corals are the easiest to grow. He figured if he could be successful, then he would try some fancier ones.

The best I could determine was one of the corals was a type of Yellow/Green polyp, which no longer has a colony, but rather a single polyp.

His parameters he measured are the following:

SG 1.025
nitrite 0.1
nitrate 10
temp 79
ph 7.8
calcium 395
mag 1400
alk 10.6

He pH tested his RO/DI water and it is 5.8.

He doesn't regularly dose anything unless the numbers fall. They stay relatively stable due to no corals in tank. When he does dose, he follows instructions on the packaging.

He does a 5 gallon water change a week on his 75gal/30 sump tank.

He is not sure how long, or what his intensity is on his lighting. It may have full power 6 bulb lights on all day, 8-12 hrs, but I'm not sure. He was going to look into it. I had originally set it to have Sunrise/Sunset lighting, and about 4 hrs full intensity, but he had to change the ballast on his light and it reset the programming. It's a nice light ATI dimmable sunpower, but the manual was horrible in explanation, and I think it gets frustrating for my Dad. I'll be going back home for Christmas, and can reset it for him then.

Any ideas on why he may be having trouble with his corals from that info?

[Reef Doctor]

In addition, he doesn't test for phosphates. I am thinking that may be a possible problem.

Also, what is a recommended amount of water change and frequency for a 75gal/30gal sump system. After he told me he changes 5 gal a week, I thought he should probably at least monthly to a larger water change. What do you all think?

The RO/DI water is pretty acidic as well at 5.8. Is there anything he can do to neutralize it since he just runs it through an auto topoff?

[chrisfont23]

20% a month will do it.