Halimedia turned white overnight

[returnofsid]

Hi all,
I've got a slight (I hope) problem. In my 75 gallon mixed reef tank, I have several areas of Halimedia. In fact, yesterday I was taking some pictures of the tank and all of the Halimedia was nice and green. This morning I woke up to a cloudy tank and while looking around to see if something had disturbed the sand bed, I noticed a large clump of Halimedia that's turned pure white overnight. I have no idea what may have caused this or why it would have turned the water cloudy. Any suggestions or advice? All corals appear to be happy and have full polyp extension. All clams also appear happy. I'm posting this as soon as I noticed this issue so haven't tested any parameters as of yet. I'll be doing that next.

Alright, test results are also off, here they are.

Ca. 380 I try to keep it at 425
Alk. 5.4 dkH!!! I keep it at 10 dkH
pH 7.4!! pH is usually at about 8.3 I just tested pH and actinics have only been on for about 20 minutes. Day lights aren't on yet. That could explain some of the low pH reading.

Ammonia undetectable
Nitrites undetectable
Nitrates undetectable

Sg 1.025
mg 1225

I'll be dosing for Alk and Ca. Hopefully this will get pH where it's needed too.

Any and all suggestions or explanations as to how this happened would be great!!

 

[returnofsid]

Hmmmm it would appear that Halimedia does indeed go sexual. I was under the impression that it didn't. Guess that's what's happened.

http://www.reefkeeping.com/issues/2004-04/nftt/index.php

 

[azgard1]

Yes it did go sexual. I have witnessed this first hand and it is explosive like a fire, you would not believe what it looks like when it happens. Do a water change to be on the safe side.

 

[returnofsid]

Did a water change. Leaving the white halimeda in there since I've learned that it's now basically aragonite and will turn to sand...lol. I would bet is is pretty explosive, seeing as how a huge colony went from nice and green one day to pure white the next. Expelling all those gamites must be quite a sight!!

 

[Sherman]

And now you wait for the new halimeda to start growing out of every nook and cranny of your reef! It's not as bad as I understand caulerpa to be, but halimeda can become pretty aggressive. It also has a major calcium and alkalinity uptake, so be careful. I remember reading in an article that halimeda is actually credited with being the single largest contributor to the building of natural reefs with its aragonite base.

 

[returnofsid]

I've had Halimeda in both of my tanks now for a couple of years. I dose Ca and Alk so that's all fine. I am aware that they absorb Ca and therefore, there's more of a demand on dosing. It's really not all that aggressive and it's easy to harvest when needed. Unlike caulerpa, when you harvest it, it's easy to get all of it. I sure do like the look of it in a tank!!! LOL For some reason, I seem to have 2 varieties of it. One grows large "leaves" and the other stays tiny. The look of the two is quite spectacular...IMO

 

[Curtswearing]

Mike,

I don't consider this a 'safe' algae. It has synchronized sporulation so if one plant goes, they all go asexual. It nuked this tank (and this picture is after a 50 % water change)

Here's the white algae

Tom lost about every coral you see in that picture.

 

[Sherman]

Wow, Curt... that's rough! I have three varieties in my 12g nano. Two that are extremely similar, standard large "leafed," and one with a smaller, lacy structure. I agree, they compliment each other well. I added them to the nano to see what I thought about them before adding them to my 120g display. I'm glad I did that, because I wouldn't want this stuff in my main display. One of the species spawns regularly, though not in such a drastic manner as has been displayed here. It will only lose a single "branch" or a few of the hex petals at a time. Then, a week later, I get new halimeda popping up somewhere else in the tank. In the photo below, the only original addition is part of what's in the back left. All the rest was spawned. The lacy stuff is behind the leather, so you can't see it here, but came in as a natural hitchhiker.

 

[Curtswearing]

Jason,

It's not a biggie. I've kept it myself. It's just a matter of degrees (I.e. how much per gallon of water). If you keep a lot of it and it goes asexual, there's going to be problems. If you only keep a little, a small waterchange or new carbon will probably do the trick. If you have massive filtration, that will likely do the trick....like I said, it's just a matter of degrees.

 

[Scooterman]

I have the smaller type of this, It had spread across my tank in spots all over. Phosphate remover made a large portion turn white but then slowly came back, right now it isn't bad but If I can remove it I will, it seems to spread sporadically & when it does, it happens fast.

 

[dnjan]

One of my objections to the stuff is that the leaves (at least the larger-leafed varieties) seem to accumulate the same place that detritus accumulates. And when I siphon, these leaves partially plug my siphon tube.

I've gotten it all out of the main tank, but there is still some in my son's 20-gal.

 

[returnofsid]

Well, it has happened again. The first time my Halimeda went sexual, only one bush of it was effected. That was back in April, when I started this thread. This morning, I woke up to a cloudy tank again and sure enough, another bush of it is pure white. When it goes sexual, it doesn't effect all of it in the tank, at least not in mine. I still have it in two areas that are nice and green. Funny thing is, it never does this in my 46, only in my 75. I'm starting to wonder if there's a correlation with Calcium levels. My 75 is predominately SPS and also has 2 clams so it sucks up the Calcium much more than my 46. In fact, right now I'm sure my CA levels are low because it hasn't been dosed in a couple of weeks.

I recently got an Octopus 150 skimmer to replace my POS Pro Clear Aquatics MS150. The Octopus has been doing an amazing job and I'm emptying the collection cup every other day. The PCA MS150 collection cup wasn't emptied in months...lol. I am curious to see if this Halimeda event effects my skimmer. Just checked and no noticable effect as of yet.

 

[Curtswearing]

Mike,

There does seem to be a "Critical Mass" component to many macroalgaes. They don't always go asexual at once. This is simply a unique characteristic of Halimeda that can happen and it's important that people understand that.

 

[returnofsid]

Thanks Curt, I'm watching the tank carefully today. It's already almost cleared up. Not near as cloudy as it was a couple hours ago. I've noticed, as with last time, no ill effect with corals or fish. Polyps are all extended normally and fish are not breathing rapidly.

I've also NOT noticed any new growth of halimeda after the last sexual period. The Halimeda simply went sexual, turned white and within a week or so, disintegrated into Aragonite. I didn't remove the offending halimeda since it was already dead. I'll do the same this time and keep an eye on my 2 remaining clumps.

I actually have more halimeda in my 46 than I do in my 75, I don't just mean more percentage either...I have MORE...lol. About once a month, I pull it out of areas I don't want it in, if it's spreading.

 

[burning2nd]

mine turns white at night...

 

[returnofsid]

burning, Halimeda always turns white at night and returns to green during the day. When it goes sexual, it almost instantly turns pure white and stays that color. Then it slowly dissolves into aragonite sand.

 

[russellaqua]

Halimeda can be an extremely productive plant. Scientific studies in the Bahamas have recorded over 400 individual plants in a 1 meter square area over a year. The average turnover rate was a new generation every 2 months. That's 6 crops per year, and 400 individuals! Yikes!

 

[returnofsid]

I do know it grows very nicely in both of my tanks. It's easy to control, is home to all kinds of beneficial critters and I really like the look and shape of it. For those considering it or who already have it, be warned, it does tax your calcium levels. If fact, I'd go as far as to say it uptakes about as much calcium as SPS of comparable size. I test and dose accordingly, as should anyone, with or without Halimeda.

I'll admit that the first time it went sexual, it did kinda freak me out waking up to a cloudy tank. Especially when I first assumed that something large had died and spiked my ammonia. After doing an ammonia test that came back zero, I was very stumped. That is until Angie pointed out my huge PURE WHITE garden of Halimeda that I'd somehow overlooked...lol. At that point, it was obvious what had happened, I calmed down and the tank cleared up within a couple of hours.