Chrysophytes, AKA "Golden Algae" - How to identify, treat and remove it from your tank!

[DarkSky]

A wikipedia image for chrysophytes.

For some time, I've been dealing with a mystery ailment in my aquarium. A wispy, slimy mass grew on almost every exposed area of my tank - no matter what I had tried, it kept coming back and stubbornly stuck with me for months.

I started my current tank in late May, early June of 2016 from completely dead material - dead rock, no sand, and a small refugium with macro algae. I was running carbon and GFO in a reactor, and had a reef octopus HOB 100 skimmer. Nutrients were almost always undetectable.

Fast forward to August. The macroalgae has been slowly turning white and breaking off, getting into the display tank. I decided to remove it from the refugium section of the sump since it clearly isn't getting enough of what it needs to grow.

Within the week, the chrysophytes moved in.



This was a video I took prior to have it checked out. It had been in the tank for months. Never bothering coral or fish, it covers nearly every free space in the aquarium. Manual removal would help for a day or two, but it'd be back as strong as ever in a few days.

I waited as long as I did thinking it would clear up on its own, but I was fast becoming annoyed and decided to start reaching and to get a positive ID so I could try another treatment.

I reached out to Dr. Capman, a member of our local reefing forum and biology professor at Augsburg College in Minneapolis. He invited me to bring a sample in so we could check it out under a few microscopes.

The first image, taken via cellphone through the optics on a microscope.

At first, we didn't know what we were looking for. There were a bunch of these cells, which look awfully similar to the wikipedia image for chrysophytes. At the time, we didn't know what we were looking at. Also in the sample were copious amounts of these long clear filaments. This might be what was giving the golden cells a structure to grow - we weren't sure.

At this point, we ruled out that it was cyano. Not quite sure what it was, we went and used a much more powerful microscope that could send different, specific wavelengths of light through the sample to see what chemicals are excited and fluoresce - potentially telling us what chemicals might be in the cells. (Forgive me, I can't remember the name of the scope, I'm but a simple software developer and not a biologist and terrible with names. )

Visible light. This shows the nucleus of the cells.

Green wavelength of light. No chemicals seemed to fluoresce with this wavelength.

Red wavelength of light. The cells fluoresce, indicating that there may be chlorophyll present in the cells.


So we finally have something to work off of - the potential presence of chlorophyll means that the cells would be photosynthetic. I had tried tackling the slime before with three separate 3-day lights outs periods with little success, it made a small dent in the slime but it always came back and my coral didn't really appreciate the low light period.

Knowing that the stuff is photosynthetic, a lights out period could harm it. How could I tackle it during the lights out period, while minimizing coral damage?

I first started by manually removing as much as I could, scrubbing every surface and scraping all of my glass. Normally when I do this, it comes back even bigger than before in a few days, but this I hoped teaming it up with a lights out period would stop it from growing back.

I then dosed #Vibrant - the liquid aquarium cleaner from @UWC. After manual removal and wrapping the tank, I dosed 1ml per 10g and waited three days.

I set my skimmer to skim VERY wet, it was pulling out a full cup every 12 hours. Something was happening, but what?



They were dying, that's what!

I think the combination of no light, manual removal getting most of the matter and Vibrant consuming the nutrients they were putting into the tank prevented them from coming back. It's been a week since I unwrapped the tank, and I've seen nary a trace. I'm still watching the tank like a hawk, but so far, it seems pretty good. I'm pretty happy with the results, and hopefully if someone out there is dealing with these, this post can help them out.

Thanks to everyone on R2R for the help in various threads, @UWC for the bacteria, and a huge thank you to Dr. Capman for the pictures and help identifying the slime.

 

[mcarroll]

Sounds like it's about gone then, eh? Love it!!! Great pics and movies too.

If you can post them, I was curious about the details of any nitrate dosing you tried. (Dose rate, observations you made along the way....anything/everything.)

KNO3 worked on mine and from what I've been able to read, there's no reason to expect that it would work less well on other chrysophytes.

(Look for my posts and pics in my Member's Tanks thread, the Potassium Nitrate thread, the Dino thread, as well as one of the Diatom threads I think...and my posts tagged #chrysophytes. LOL...it was an adventure.

But I'm now happily tending a crop of plain-looking cyano and a little bit of green hair algae while some of the coraline algae grows back. The Hydnophora has almost doubled in size (from almost nothing left). In fact all my corals have been growing like crazy since. NO MORE CHRYSOPHYTES.

 

[DarkSky]

Sounds like it's about gone then, eh? Love it!!! Great pics and movies too.

If you can post them, I was curious about the details of any nitrate dosing you tried. (Dose rate, observations you made along the way....anything/everything.)

KNO3 worked on mine and from what I've been able to read, there's no reason to expect that it would work less well on other chrysophytes.

(Look for my posts and pics in my Member's Tanks thread, the Potassium Nitrate thread, the Dino thread, as well as one of the Diatom threads I think...and my posts tagged #chrysophytes. LOL...it was an adventure.

But I'm now happily tending a crop of plain-looking cyano and a little bit of green hair algae while some of the coraline algae grows back. The Hydnophora has almost doubled in size (from almost nothing left). In fact all my corals have been growing like crazy since. NO MORE CHRYSOPHYTES.

Sure thing!

I started by dosing 5ml daily (1ml per gallon approximately) until I started having detectable levels of around 2-5ppm (test kit isn't that accurate).
Once I hit those levels, I dialed back the dosage to 1-2ml daily, eventually lowering the dosage even further until I was around 5ml a week total to keep my NO3 around 2-5ppm.

The crysophytes darkened and got much worse, so I stopped with this method after about 10 days.

I haven't had to resume dosing as my heavier feeding and removal of GFO seems to keep my nutrient levels where I want them, in the 2-5ppm range.

 

[mcarroll]

Hopefully you don't have to experiment any further, but just in case...

10 days wasn't enough. It's hard to really say, but I might guess that you were about 1/3 to 1/2 way through the treatment.

It's also possible you needed even less of a dose. It was my feeling that the it was more the regular/consistent nutrient additions than the particular amount I was adding or the number I saw on the test kit. In fact I saw results before I ever saw a number on my nitrate kit. How big is your tank?

I think I was dosing 5mL per day into a 100 gallon system for most of my time, with just a few drops of amino acid solution. I would skip the aminos if I had to do it over....just don't think they did much.

The darkening and worsening was a phase. Kick up your physical removal activities.

I generally spend almost no time on my tank these days, but during this I was in the tank with a toothbrush almost every day getting that nasty junk off my Hydno. I even had to use a siphon tube a few times to suck the junk out. Bother!!!

 

[DarkSky]

Hopefully you don't have to experiment any further, but just in case...

10 days wasn't enough. It's hard to really say, but I might guess that you were about 1/3 to 1/2 way through the treatment.

It's also possible you needed even less of a dose. It was my feeling that the it was more the regular/consistent nutrient additions than the particular amount I was adding or the number I saw on the test kit. In fact I saw results before I ever saw a number on my nitrate kit. How big is your tank?

I think I was dosing 5mL per day into a 100 gallon system for most of my time, with just a few drops of amino acid solution. I would skip the aminos if I had to do it over....just don't think they did much.

The darkening and worsening was a phase. Kick up your physical removal activities.

I generally spend almost no time on my tank these days, but during this I was in the tank with a toothbrush almost every day getting that nasty junk off my Hydno. I even had to use a siphon tube a few times to suck the junk out. Bother!!!

It's possible that it was too short of a period. I just noticed negative effects and decided to try the no lights route. I have a 45g tank, with around 55-60g of total volume.

 

[AdamNC]

Following as I'm having the same issue. At the moment I'm on a second round of Chemiclean after scrubbing the rocks. I'll also try wrapping the tank. I've turned off my AC70 that holds my carbon and Purigen but left my skimmer running for O2 and just removed the collection cup. Scubbing the rocks about once a week is the only thing that seems to keep it at bay.

Here's what I'm dealing with.
https://www.reef2reef.com/threads/cant-kill-this-stuff.269650/

 

[DarkSky]

Following as I'm having the same issue. At the moment I'm on a second round of Chemiclean after scrubbing the rocks. I'll also try wrapping the tank. I've turned off my AC70 that holds my carbon and Purigen but left my skimmer running for O2 and just removed the collection cup. Scubbing the rocks about once a week is the only thing that seems to keep it at bay.

Here's what I'm dealing with.
https://www.reef2reef.com/threads/cant-kill-this-stuff.269650/

That looks familiar! Make sure you do as much physical removal as you can before wrapping your tank. Scrub every square I checked and suck it out. Run your skimmer with its cup because all that die off is going to pick nutrients in the water.

Are you going to try a bacteria supplement as well? It'd be interesting to see if it helped or not, I believe it did personally.

Take some before/after videos for me!

 

[AdamNC]

The only bacteria I use is what's in the tank and feeding it NoPoX for carbon dosing. I cut all feeding except for my fish which I'm only feeding pellets and making sure each and every pellet is eaten. Before this recent round of Chemiclean I did a 25% water change, then just now did another 25% water change and then in 2 more days going to do another 25% water change. The only thing I'm dosing now is Red Sea Colors ADCD.

 

[mcarroll]

@AdamNC I'd lay off of carbon dosing (shut it down slowly) until you have this licked.

You want ANY OTHER KIND OF ALGAE to be happy enough to compete with this stuff and the preferably kinds of algae need the nitrogen you're doing away with by way of carbon dosing.

Something has to fill in the areas you clear on the rocks manually. If nothing else does – this stuff will.

See what happens for at least a week after Chemiclean is finished. If you get to the point that you think it's not working (didn't work for mine at all) then I'd switch gears and start fostering "dirty algae". Chrysophytes are a clean water "algae" as far as I can tell. Keep PO4 and NO3 both above zero.

 

[AdamNC]

Here's about a week later, getting some GHA now but I can deal with a little bit of that

 

[reeferfoxx]

Chrysophytes are a form of Diatoms. I contribute it to excess silicates and po4. Not surprised vibrant knocked it out as it reduces po4. I took a different route and tackled silicate removal with running GFO for 24 hours and took maybe 3 days and it was gone.

 

[mcarroll]

Chrysophytes are a form of Diatoms. I contribute it to excess silicates and po4. Not surprised vibrant knocked it out as it reduces po4. I took a different route and tackled silicate removal with running GFO for 24 hours and took maybe 3 days and it was gone.

Kind of a myth I guess. I even ran into them being called "Golden Diatoms". I think I mentioned them like this in one of my posts when I was trying to figure them out.

Apparently diatoms, cyano and dino's (among other things) are all known associates with chrysophytes.

 

[reeferfoxx]

Kind of a myth I guess. I even ran into them being called "Golden Diatoms". I think I mentioned them like this in one of my posts when I was trying to figure them out.

Apparently diatoms, cyano and dino's (among other things) are all known associates with chrysophytes.

Well diatoms and dinos are protists. Cyano is a bacteria. The correlation between chrysos and diatoms is true and not a myth. That said, chrysophytes feed on plankton but are made up of silicates. Now, how we ID them is up in the air. But one thing that all versions of chrysophytes have is its genetic makeup of containing silicates.

 

[mcarroll]

The postings on Wikipedia for chrysophytes is confusing – that might be part of the problem. And lack of positive ID in general...

I know diatoms are referred to as separate kind of critter in the grouping known as heterokonts....I don't know too much more than that, or what that even means. Sounds like heterokont is a bit of a catch-all term like "protist".

I wish I had a scope so I could speak with any degree of certainty or authority about what I had. It looked a lot like what I see in these pictures, but that doesn't narrow it down or clarify things very much.

Mostly what I know is that the KNO3 treatment worked....the nasty stuff like in the pictures here was apparently populated in pretty short order by other algae – which I presumed was cyano, diatoms and dinoflagellates...hopefully more. The more I scrubbed it away, the less the nasty stuff returned at all and the more the other stuff seemed to exclude it. It wasn't long before I saw some patches of corline growing! I don't have time to look up mu old pics (wish that was easier here on R2R) but if you could look up what my Hydnphora was like before chrysophytes and what it's looked like recently....it was receding FAST.....my work with a toothbrush + KN03 dosing is what saved it....and like I said, it's now growing back as a result. Take heart!!!

Since then, corals, pods and snails have all resumed growing and eating. I still have quite a bit of cyano around, as well as some green algae growth in tufts in two places, as well as some green film on the glass. Yes!! I quit dosing and am doing nothing but feeding at this point – controlled, finite amounts, yet way more than my barnacle blennies could eat. (Generally this means feeding something like ROE that both corals and fish will eat, but I've been experimenting.) I've even seen some bristleworms and limpets around! All of these guys were gone when things went toxic.

Also, I just discovered a good article last night that I'll post here soon where they saw the same effect of nutrient enrichment during scientific observation of brown tide.

 

[mcarroll]

Chrysophytes are a form of Diatoms. I contribute it to excess silicates and po4. Not surprised vibrant knocked it out as it reduces po4. I took a different route and tackled silicate removal with running GFO for 24 hours and took maybe 3 days and it was gone.

I did go through a phase where I thought what I had might have been diatoms and I tried the <24 hours GFO treatment for about a week. (No resources to go beyond a week.) It may have helped things progress, but I can't be sure – there was no obvious or immediate effect. However, I did not feel like it was a waste and probably would have continued doing it for one more week if I had the materials.

I was also using a small, regularly-changed amount of activated carbon during this period. (I normally use neither...and that's were I am now.)

 

[DarkSky]

Mostly what I know is that the KNO3 treatment worked....the nasty stuff like in the pictures here was apparently populated in pretty short order by other algae – which I presumed was cyano, diatoms and dinoflagellates...hopefully more.

This was true from what we saw under the scope when looking at my samples. 90% of the matter were the chrysophyte cells, the remaining were dinos and diatoms.

 

[reeferfoxx]

I did go through a phase where I thought what I had might have been diatoms and I tried the <24 hours GFO treatment for about a week. (No resources to go beyond a week.) It may have helped things progress, but I can't be sure – there was no obvious or immediate effect. However, I did not feel like it was a waste and probably would have continued doing it for one more week if I had the materials.

I was also using a small, regularly-changed amount of activated carbon during this period. (I normally use neither...and that's were I am now.)

I remember your hydnphora pics and what you had. It always had me scratching my head. When you described dosing kno3, i couldnt help but think about the Redfield ratio and the promotion of plankton also how no3 helps release "locked" po4 and promote consumption. Also I agree that the Wikipedia description confusing. Though slightly vague the Encyclopedia description is straight forword and can help direct you more. I think your chrysophytes were the ameboid form or without cellular walls. Any type of mulm contains oil and yours definitely had a mulm appearance.
When I used the GFO, I had already begun dosing kno3 and maybe inadvertently neglecting any connection. Manual removal was essential as well.

 

[DarkSky]

Yes, manual removal seems key to getting rid of this stuff. I had tried before with just manually removing it but it came back. I think you need to take a few different avenues of treatment to kick it completely.

 

[Catchemall]

Manual removal and stump remover potassium nitrate is the ticket for me I also kicked back on my algae scrubber as well and my tank is starting to look great again. Coloration and growth after the stump remover is insane too!

 

[Wingzinco]

Hello @DarkSky. First, thanks for your post, I've been digging for quite some time and have tried several things, but am dealing with this same stuff. I'm planning on giving this method a try. Did you ever have more issues with this after this treatment?