Fixing a very screwed up tank

[s1214215]

OH MY GOD :eek3:

I just arrived in Australia to see a friend after a year. When I left, his 600ltr tank on which little expense was spared, was pristine, with little excess nutrients - I had set it up.

Now, half the corals are dead, half the rock is covered in cyano, and the reef has almost collapsed .

OK.. Hes asked me to fix it and he wil get a reeftank maintanance guy to do a month visit to keep it on the right track this time. OK says I.... BUT

1: What should I do about all the cyano on the live rock. Scrub it off? Luckily half of it is smothered in pink coralline algae which has kept it off... Or what do you think? (must say its amazing corraline growth for one year when there was little present before. It must have liked something)

2: As the reef had collapsed - due to his pulling out dead corals - this lead to dead spots I guess and helped the nutrient issue to develop. So I will reset the reef, and put in better water flow through it. Naturally I will do water changed to address the nutient problem.

3: Could the old metal halide bulbs be part of the cause of the Cyano? They are over a year old. I think swap them out.

4: He was advised to put a crushed coral bed (3 inch deep) in his sump to act like a DSB. Yikes - would this act as a nutrient sink? I think get rid of it and fill that area of the sump with caulerpas and a lighting system to kick in after tank lights go out at night..

I think that these are the areas leading to the problem of the cyano and this is how to fix it (other than shooting my friend which may give me some joy after I fix this disaster ). What do you have to say Reefland people?

[Ninong]

OH MY GOD :eek3:

I just arrived in Australia to see a friend after a year. When I left, his 600ltr tank on which little expense was spared, was pristine, with little excess nutrients - I had set it up.

Now, half the corals are dead, half the rock is covered in cyano, and the reef has almost collapsed .

OK.. Hes asked me to fix it and he wil get a reeftank maintanance guy to do a month visit to keep it on the right track this time. OK says I.... BUT

1: What should I do about all the cyano on the live rock. Scrub it off?

What you should do now depends on your assessment of the situation. You're the one looking at the tank. Do you think it would be better to re-start the entire tank?

IF you're going to remove any of the live rock, then of course you should rinse it off in saltwater to remove any cyanobacteria. How much scrubbing you do is up to you.

You could always decide to just work with the tank the way it is and tackle the water quality issues and the lighting and let nature take its course.

3: Could the old metal halide bulbs be part of the cause of the Cyano? They are over a year old.

Lighting is one of the factors that affect cyanobacteria. It is not the only factor. Shifts to the red end of the spectrum favor cyano. I have no cyano whatsoever in my 120-gal tank and my 250w 10,000K HQI DE lamps are 20 months old. They have been run an average of only 7 hrs/day but they are ready to be replaced. I've been putting it off for the past few months. I was planning on replacing them at 16 months but just haven't gotten around to it yet. Not all lamps age the same. Some lamps degrade much faster than others. It's not just a matter of loss of intensity but also a matter of changes to the original spectral distribution of the lamp. This is why the popular Radium 400w 20,000K lamps have to be replaced after only 6-8 months -- they shift very fast compared to most 10,000K lamps.

4: He was advised to put a crushed coral bed (3 inch deep) in his sump to act like a DSB. Yikes - would this act as a nutrient sink?

I don't care for crushed coral DSBs myself.

[s1214215]

I don't care for crushed coral DSBs myself.[/QUOTE]

What do you think about the idea of completely removing the crushed coral base in the main tank area and replacing it with a 1.5 to 2 deep inch aragonite sand bed? The current bed is full of mulm and I think a finer bed would be less likely to collect mulm. The aragonite is 1mm grade. I can get calcium carbonate to do the same job and its oolitic in grade. What say you Ninong?

I just want to cut down all possible areas that may be nutrient traps. The owner of this tank is not cut out to be a reefkeeper, but will get a maintanance guy to look after it monthly or possibly fortnitely. I just am looking for ways to make this tank run smoother.

Thanks for the other suggestions.. I will scrub some of the rock under salt water as you suggested and swap out the bulbs to 10K bulbs. I think they were the 20Ks that you mentioned and would be well past the used by date. I will also get rid of the crushed coral in the sump, and replace it with Caulerpas and a light.