Sounds like you have several issues. First you need more light if you want sps. Secondly your phosphates were high you added rowa and pulled it out to fast and that is very hard on sps. And as far as algae goes I would think it was due to your high phosphates. If you wonna fix your algae problem there's only one effective way to do that. And that would be black out your tank. It amazes. Me people still go to all these great lengths to get rid of it when all you have to do is give your Tank 3 or 4 days of complete darkness. After that I bet money 95% of your algae is gone. I would also remove some rowa out of your reactor. That's just my opinion but that's what I would do. Not sure how much flow you have in your tank but increasing that would also prevent algae and detrius. Good luck

I did a 4-day blackout and it weakened, but didn't eradicate, my GHA

I'd use new water for cycling your new rock. Your tank water will likely add stuff you are trying to remove

I know SPS don't like change, esp any kind of rapid change. Earlier this year, my P04 got a little higher, from near zero (hanna digital checker) to about 0.10, and noticed some of my SPS lose color and grow slower. I also disconnected my bio pellet reactor, and my N03 crept up to 30 ppm. I am sure that didn't help either. And GHA took off with a vengeance, too.

Then this summer, I had a problem where my KH doser line plugged, and my KH fell to 5 before I figured that out (was away a lot). Once I fixed that, I upped it to about 9 (miscalculated and did it too fast). After that, I noticed real problems,... white burnt tips on some of my SPS, and big loss in color as well as some STN on some SPS.

Took me a while to get everything stabilized, and meanwhile some of the STN turned into RTN, and lost some of my prized SPS. It took about a month or more after my tank was stabilized before my SPS started to turn around.

Good news, though, is that everything now is looking much better, and growth and color is returning (although still a ways to go from what I had before). I think it just needs more time now, and have to keep everything very constant and stable, esp that KH. My GHA has pretty well disappeared too (needed consistent zero P04 and zero N03 before that let up).

Last time I tried a 3 day blackout I couldn't find my total pitch black sheets n just used a bunch if bed sheets lol. A bit of lights still went through. When I finish the 3 days I did notice a bit of algae gone but my sps looked worse and had some RTN. Since my tank is very delicate right now is it a good idea to do another blackout or wait till it heals? K I'll make new water for my new rocks instead of tank water

Debris removal. Nuff said. When this is lacking, all we do is throw a mess of "solutions" at the system trying to correct it throwing things out of balance, waisting time, money, media, equipment, livestock, chemicals, etc. when this becomes the main focus of husbandry practice, many of these "solutions" become irrelevant. Granted allot of these solutions can work fantastic and each can have a successful benefit when used correctly but every action has a reaction and once we start adding in the potential for human error well...

The most valuable and effective piece of equipment a hobbyist can have at there disposal costs next to nothing, is available almost anywhere, comes in a variety of colors, sizes, and can be customized at any length, can be upgraded with unique attachments all suited for an individuals needs, and can ward off so many problems we constantly encounter. Of coarse assuming all parameters are kept in check through equal diligence.

Yea I agree about Derris removal. Tons and tons of Derris comes out of my rocks when I turkey blast it but not enough is going down my hang on back overflow to be picked up in my skimmer in time b4 it sets back into the rocks. I have tons of 1 lbs rocks in my tank so Derris get traps so easily this is why I bought all new rocks so I can change my aquascape to allow a lot of flow around rocks. Ok I do have one of those hang on back aquaclear filters but what should i put in it since I'm already running carbon in my reactor?

If you can't get the debris out through the overflow you gotta get it out through siphon. If you have a sump and filter sock just run siphon from display into sock placed in sump. You can siphon all day long like that if you want. Promptly remove sock after finished. Make that part of your regular maintenance schedule, new rocks or not.

I don't think there's anything in your rocks. Nutrients have to be incredibly low to inhibit the growth of some kinds of "hair" algae, much lower than most people can or want to run their tanks at. It's why it's an invasive species in large parts of the world to which it has been introduced by humans.

In nature, it's not low nutrients that keep it in check (thought that can help), but a massive cohort of herbivores that suppress it enough to favour stony corals.

Hair algae, like most things in the ocean that need to compete for limited substrate, wage chemical war on their competition. They emit all sorts of nasty alellopathic chemicals that range from halting the growth of corals, to outright killing them.

If I were a betting man, I'd say you introduced spores of a particularly nasty kind of hair algae on a coral or frag, conditions were favourable for it, you don't have anything that eats it, and now it's killing your coral. Yes, you should keep nutrients within the range of the reef you're trying to keep - something that is hard to measure with rampant growth of a problem algae as it will mask your inputs while being a better competitor for nutrients than your gfo reactor - but you also need to kill that algae.

When weeds start growing in your garden, it doesn't necessarily mean there is something wrong with your soil. It means weed seeds have made it in to the garden. You wouldn't try to leach the soil of all nitrogen and phosphorous to get them out - you'd weed it.

My suggestion is to find some AlgaefixMarine, and nuke the heck out of that algae. Nutrients aside, I bet your surviving corals will see near instant improvement once the majority of that algae is dead. Even if you do have a nutrient 'problem', you're never going to be able to properly diagnose it, or put in a system that's better at competing for them with a lush growth of hair algae in the tank. It's always the tanks with the worst algae problems that measure '0' nitrate and phosphate, which, for the record means there's not a whole of anything for GFO to suck out of the water column.

Okay? Seems like backwards thinking to me. I again will say, go after the root cause. You've said already you have an issue with debris buildup. It's very simple. Get it out. And work to keep it out. If you want to keep poo as a pet then by all means, invest in all the livestock, all the equipment and medias and chemicals, all the frustration, to properly house this pet. We have some very ingenious practices to successful house these poo pets in our system so this may in deed be your best approach if you wish to keep them. But keeping these poo pets has led you to the place you are today. So ask yourself if keeping poo is part of the practices you wish to continue to engage in.

Again, there are allot of great means to help you control nutrients within your system and I myself would encourage you to run gfo and you may in fact want to include some livestock to help you control it. But you have to remember these approaches are all a day late to the party. They do not address the root cause. Get the crap out before it even becomes an issue.

I'd agree with this, but not because I think the detritus itself is causing nutrient issues. If the detritus is building up, it means the export systems aren't working very well and that there's dead spots. By the time you see it as 'detritus', it's pretty much inert refractory organic matter, most of which is produced as a byproduct bacterial metabolism and is as decomposed as it's ever going to get. Vacuuming up the detritus is like vacuuming up a pot plat that's been knocked over on to your carpet - the dirt's already spilled, so to speak.

The stuff you should care about, uneaten food and fish poo, gets scavenged and eaten by critters and bacteria very quickly. Yes, detritus is the eventual end result, but if you've got detritus accumulating it means you probably don't have enough flow in enough places to get the stuff you should care about to your skimmer/filter socks before it breaks down. Vacuuming up the mess is pointless. preventing the mess from accumulating in the first place is important. Perhaps we're arguing the same point.

However, I still stand by the premise that the "root cause" of many problem algaes is no more complicated than the presence of that algae in the first place. Just like the root cause of dandelions in my back yard is the dandelions growing in the alley behind it. A great many (most?) of the corals we keep come from waters with enough nutrients in them to support verdant growth of macro and micro algae. Reefs dying under a choking chemical assault from lush fields of simple 'hair' type algae is a well known consequence of humans fishing out all the herbivores on a reef.

The OP has already stated that his PO4 readings are undetectable, because the algae is sucking it up as fast as it's produced. GFO is great at lowering PO4 when it's present in detectable quantities, that's been shown in test after test. But he doesn't have any PO4 in his water to lower. The algae already sucked it all up. And what's a better competitor for new P as it's added: A bed of algae in the same box where all the P is added, with an absorbable surface area probably measured in square kms, receiving 100% of the flow of the system across it every few minutes, or a teeny tiny reactor in the sump that gets the equivalent of 100% of the tank's water through it every few hours? On top of that the algae is producing a slew of tannins and noxious chemicals designed over hundreds of millions of years specifically to kill the competition.

Step one should be removing the algae. Step two should be adding flow and rearranging the rocks. Step three, once the algae is dead and gone, should be diagnosing whether a nutrient problem actually exists or not. If the OP removes all the algae and phosphate and nitrate levels climb to unacceptable levels, then there's things that can be done. But they might not, and anything you do to try and control nutrients while the algae is in there is going to be like trying to roll a boulder uphill.

There is a simple, safe, and effective treatment for almost all kinds of hair algae. Thousands of people (including myself) have used it, and other than a few anecdotal cases of some shrimp or some coral reacting negatively, most people (including myself) see an immediate improvement in the vigour and colour of their corals once the hair algae starts to die.