Red / Brown Algae

[Rodders]

Hi All,

My first post: I have a 10 year mature reef aquarium using live rock filtration with protein skimmer and 4 power heads in tank 46" x 28" x 18" with no sump. 11 community fish.

Over the last 6 months, a red / brown algae has developed. I have changed the T5 lights (on 8 hours in 24) 20% water change with RO water every 2 weeks. The corals have died off except the hardy soft corals as seen in photo (attached). Protein skimmer working well. Feed frozen variety (definitely not over feeding).
In years gone by, the system was working well and beautiful.
Condition of water is - good (amonia, nitrate, nitrite all at appropriate levels)

If you can advise me on what I need to do to return my tank back to its original splendour, I will be very grateful. I look forward to your replies.

Rodders

 

[FishyReef]

Welcome! A few more questions for you - have you added anything or made any other changes to your tank (besides changing the T5 bulbs) in the last 6 months since you started noticing the problem? What are your phosphate levels? Also, can you get some close up shots of the algae so that we can see its structure better?

 

[ErinCahir]

Also could we get a list of the fish you have in the tank and how long you've had them?

What do you have for a clean up crew (snails, crabs, etc)?

 

[Rodders]

Thanks for your interest in my problem.

Here are the details:
Attached are two close ups of the algae problem - best photo I can take!
In the last 6 moths since the problem has developed, I have not knowingly changed anything.
I confess, I do not check the phosphate levels regularly. A few years ago, I used to use phosphate pellets but they didn't sem to make any difference to the water quality.
I have taken 2 water samples to my local aquarium shop over the last two months and they have confirmed the quality of the water is within the accepted parameters.
Live stock:
(All fish are at least 5 years old)
1 Yellow Tang
1 Queen Angel
5 Yellow Tailed Blue Damsels
1 Wreck Fish
2 Clown Fish (10 years old)
1 Red Brittle Star
8 or so Turbo Snails
4 Red Legged Hermit Crabs
1 Star Fish

I look forward to your further comments.
Many thanks,
Rodders

 

[FishyReef]

It looks like cyano. Do you make your own RO water? If so, how long since you changed the filters? And also, I'd recommend picking up a basic test kit to test your parameters. Your LFS might be saying they are within acceptable limits, but what is acceptable to them and what is acceptable for a cyano free and coral thriving tank could be vastly different. If you do pick up a test kit it would be helpful to us if you could post up your numbers. You don't get cyano and dying corals out of the blue so something is up with your water quality even if the LFS is telling you otherwise...

Edit - one other thought/question - are the corals that you lost ones that you'd had for awhile? Its possible that your angel has developed a taste for corals and that could explain those losses....

 

[Cathic]

Eeeek! That is a pretty bad case, you should probably do a water change of 30% and try to suck out as much of it as you can with a siphon while you do it. Id also get a liquid test kit, and not strips. I know some places to use strips or "all in one" tests and they are never accurate for what our needs are. You can grab a decent one for around $30-$40 that will test your basics. Also, how often are you cleaning your equipment, as your powerheads collect detritus and other particles they get clogged and even a little can drastically reduce the flow in the tank.

On a side note, how much trust do you put into your LFS? Has your water supply changed any? Are you missing any livestock?

 

[Rodders]

Thanks so much for the advice.
Tomorrow, I'll buy a high quality test kit and post you my results.
I have recently purchased a new high grade RO unit, so I'm pretty sure the water quality is good when it enters the tank during the water changes.
I'll take your advice and do a 30% water change and try to syphon out as much cyano as possible. However, I have been working really hard at all this for the last six months and the problem is getting worse.
I agree about not taking too much notice from the LFS. They mean well but tend to be staffed by young lads with limited knowledge of the chemistry and biology of this complex hobby.
Before I sign off, I need to thank you guys again as I have just about come to the end of the line and have been considering converting the aquarium to a fresh water system. If you can help get me through this dodgy patch, I will be up and running again, full of optimism.
Interestingly, I was expecting you to suggest that I purchase a mechanical / chemical filter system to support the live rock system, but this has not been mentioned! Is there any mileage in going down this route?
Rodders

 

[andysgirl8800]

One other question, what type of lights do you use? How old are the bulbs?

 

[Rodders]

The lighting system is 3 marine white T5 tubes and 1 blue T5 tube. They are 'on' for 8 hours in 24. They were changed 6 weeks ago.