Corals withdrawn - hydrogen sulphide problem??

[ricardomax]

Hi! I have a 400L reef tank, set up using live rock and sand but no filtration. It's been running about a year with absolutely no problems, and everything appears stable. I have 8000L/hr powerheads, protein skimmer and wave box. There are some inverts, and about 8 fish. I haven't done any water changes at all over the year, but add trace elements on a regular basis. I use polished RO water to top up the tank.

My question is kind of in two parts...

About a month ago I added a sand-sifting starfish, as there wasn't really anything to turn over the sand. Very soon after, brown algae started appearing on the sand. It's extremely fine and can't be picked up and is a very thin covering.

As part of my investigation into this algae I poked in the sand a bit... and found about 1cm down it became quite black. Now my corals (within the last week or so) have become very withdrawn. Nothing so far has died and all water checks are fine, apart from nitrite and ammonia very slightly elevated (nitrite 0.05, ammonia 0.25). Nitrate is zero and pH varies during the day from about 7.8 to 8.3 (I'm trying to raise this slowly at the moment.)

So - do you think the starfish has released nutrients which account for the brown algae? And has my poking about released hydrogen sulphide/sulfide or ammonia/nitrite from the sand? There is no smell of rotten eggs. Would that be causing the withdrawn corals?

Sorry for the long post! Hope you can help!!
Thanks
Richard:frustrat:

 

[yote]

Yep,The star has probably released the nutrients.
Yeah the sand poking most likely released a bit of bad gas.
And yeah,The elevated ammonia and nitrite is causing your corals to stay closed.

Heres how I look at water changes.Even though you can get by with them,they still need to be done.Its kinda like changing the oil in your vehicle.You may get by for a while without changing it.But its eventually going to cost you 3Xs as much in the long run.

 

[ccCapt]

Few questions:
How deep is your sandbed?
Do you use a skimmer?
What exactly are you dosing, and do you test for EVERYTHING you dose?
Why no water changes?
What is polished RO water?

Nitrite and ammonia means something died and is decaying in your tank. Have you seen the star lately? The decomposition will release nutrients to fuel your brown algea...which may also be diatoms.

 

[ricardomax]

Hi - thanks for the replies. Sandbed is probably about an inch deep, maybe a tiny bit more. I do have a skimmer. I'm dosing with Seachem Reef Plus to replace any lost trace elements - but no, I don't test for everything (magnesium etc).I haven't done water changes for a couple of reasons - first if I'm being honest it's to save the effort... (I know that's bad!! :P) but also a number of books I've read suggest it's better not to do water changes if you don't need to - and since the nitrate has never risen thanks to the LR I've not bothered... Polished RO is just with a de-ionising resin used after the RO filter to get rid of the last bit of dissolved solids.And all the critters are accounted for - if there's something decaying it's probably a snail somewhere, but I'm inclined to think it's my poking about in the sand. The sand hasn't been turned over properly at all for about 10mths, so I guess it's pretty filthy... Was thinking of giving the star a couple of months to adjust and then maybe add something else to help it??CheersR

 

[Bifferwine]

When it comes to doing water changes vs. not doing water changes, the consensus is that doing regular water changes is essential. Very few people believe that you can successfully keep a tank long term without water changes! So, no offense, but maybe you were just looking for the books that say that you don't need to do water changes, because I don't know of one hardcore reefer that doesn't do them.

I agree with Yote, that maybe mixing up the sandbed after all this time has started a minicycle... It's a good idea to have a cleaner crew that will keep the sandbed clean from the start in order to avoid stuff like this from happening. Hopefully the cycle will pass quickly and won't do any permanent damage to any of your animals. If you want, you can try adding a product called AmmoLock and see if that helps clear up the ammonia and nitrites. When your ammonia and nitrites get back down to zero, you should add a bunch of nassarius snails to keep the sandbed clean from now on.

 

[reeffreak]

Here's my observation......
I don't believe your sand bed is deep enough to cause the gas to crash your system.Disturbing it could of cause that small ammonia and nitrite spike.
Any ammonia and nitrite,even very low amounts can damage or kill corals and fish.
I'm not a big fan of sand sifting sea stars.They consume the fauna which consume detritus and micro algae.
All I can say about water changes-its better to do them regardless if your water quality is good.You can't test for all trace elements that may or may not be used up.

 

[Doc]

there is no real good reason to avoid doing water changes. this is a time intensive hobby. doing regular water changes erases so many mistakes that can happen with our tanks. it is critical for the health of corals and fish. I would recommend doing a bigger water change right now, say 25% to get rid of the ammonia and nitrites. Use a premium sea salt and start doing changes weekly from now on.

-Doc

 

[jhnrb]

I agree with reeffreak. well said. Doc is on the track too as are others. as to how much water to change, at least/minimum 10% a week for a while will help. as for the star, you will have to just wait it out until the star moves through the sand bed. personally your sand bed is not deep enough for a sand sifting star. it will most likely starve eventually and could have adverse effects on your entire system. Good luck, keep us posted on your progress and what you decide to do.

 

[ricardomax]

Thanks guys - appreciate the help. I have bitten the bullet and am going to do water changes from now on :claphands

Made up enough saltwater yesterday for a 10% change so will do that later today, then make up some more and repeat in a few days.

I've also adjusted my powerheads slightly to improve the flow a bit, and will invest I think in another one (will then be 11,000lpr in 400l tank).

I have now been getting some hydrogen sulphide/rotten egg whiffs, so hopefully the new regime will settle all this down and improve the flow near/through the sand before anything dies...
Will keep you posted!