Help with corals

[hammoz]

Hi

I have had my tank for just over 1 year and everything was fine, but over the last 2 months my corals have retracted. I do the normal maintenance things ie water change every 2 weeks, regualr water tests (also perfect). Others things have started to grow in the tank that I havent put in (urchin, snails, star fish) so I know the water is ok.
I did think it was the light so I bought a replacement but nothing happened (18w blue/white aquaone) Then I thought it was the filtration so I removed the carbon and phosterate sponge, still no change. Then I thought it was a change in outside air temp (I am in Australia and we went into winter at the same time as this problem) So I increased my water temp from about 25 to 27, still nothing. So I increased my light on hours from 9 to 10, still nothing. Its a 35L tank so only small one. I have started to add some calcium and I use filter fish food supplement too.
What is puzzling is that it used to be really good, so when people say you need better filter or stronger lights its like, well they were fine before so why would I need to change that now?

Any suggestions?

 

[joy13]

What type of corals do you have? I know that some get bothered by pests like nudibranch and close up. I am sure there are other pests that will cause them to close as well.

 

[CaptainAhab]

RE: perfect water tests .. What are the results? It looks like you have some algae growth going on there. Be interested to know your nitrate and phosphate readings. Remember, if you have an algae outbreak and your nitrate/phosphate readings are low it's probably because the algae is consuming it and the low reading is misleading.

How often do you feed? Are there any fish in the tank?

18w over 35L(10g) is low

What are you using for flow?

 

[melosu58]

My guess would be the lighting. Your lighting is very low. Would be interested in the answers that the captain asked

 

[Kurt_Nelson]

Yup... actual numbers for the water chemistry tests will help us help you. Specifically... salinity, pH, alkalinity, calcium, nitrates, ammonia, and nitrites. Phosphate, if possible.

For a year old tank, I'd expect to see a LOT more coralline algae present - even with low lighting. I suspect something is up with your cal/alk levels. Did you start to add the calcium before or after the corals starting retracting?

Also... what kind of fish do you have in there, and when did you add it?

[Edit: Also... things could have been good for a while, even with inadequate flow or lighting, because it can take a while before a coral shows the effects of either of the two. They can "survive" quite a while in inadequate conditions before finally just giving up and running out of extra energy to stay alive.]

 

[juice28]

im no pro but from the look of the tank you have some LPS's but like Kurt said, there really is no coralline in the tank ive had my tank almost half the time your has been up and Ive it on my filter siphon, powerheads glass...heater (that I never use) everything is covered well not completley but enough to say that, " you have coralline growing everywhere.. maybe your calcium is really low.. I mean you have a small tank.. if I did my math right,you only have about a 10 gallon tank( 3.7 liters = 1 us gallon) your light should be ok i would think but after a year your tank walls and rock should be covered with algae, if your calcium was right/high. your tank still looks brand new. that is just my opinion, im still a newbie myself so I could very well be wrong

 

[Mitchell0605]

Nice to see another Aussie here. I can definately say its not winter man. My corals are fine still. I agree with above, maybe your lighting is not godd enough.

 

[hammoz]

Hi All

thanks for the advice so far. The salinity level is 1.026, I dont know the exact readings for the nit/phos etc I will get the water tested at the weekend and get the numbers. But I remember the last time I did which was last weekend I was told the nitrate was 0, does that make sense?

The corals were doing ok then I started adding calcium and they started to go really well, I am still adding this in the same quantity. I have a goby in the tank and I feed with either brime or mysid shrimp twice a day. I do add baby brine one a week hoping this will encourage the corals to open.

I used to get the normal green algae growing, but this stopped the same time as the corals retracted?

One more thought is that an urchin has grown in the tank, would these guys eat coral?

 

[Mitchell0605]

Urchins eat algae. Maybe where your algae got to? lol

 

[joy13]

Won't an urchin feed on coral once the algae is gone?

 

[Kurt_Nelson]

You need to do your own testing if you're adding supplements. Adding stuff without testing will either waste money, kill things, or both. If you're adding calcium without knowing what your calcium levels are to start with, how do you know you need to add any? And how much. You really need to know what your calcium and alkalinity levels are, as well as pH. My guess is that one of the three are out of whack.

Regarding urchins... they'll eat coralline algae, so that could explain your lack of it. But I'd still expect to see *some* of it, somewhere. As far as I know, they leave coral alone.

 

[rive1404]

From what I can tell, and I'm probably mistaken, but if that is a Pencil Urchin then it will eat coral. But you're light seems pretty low. I'd stick with zoas, shrooms, softies, and some non-photosynthetic coral.

 

[juice28]

i have a pencil urchin and he hasnet touched ant my softies or LPS's but i have alot of algae and I spot feed him a piece of a red algae sheet probably once a week also.. I also have a pincushion who grazes constantly and I spot him/her/it also, I don not think your urchin would be the cause for your problem unless it was starving and that was the only thing to eat...what type of coral do youhave? it looks like duncans or some type of branching LPS