Yes thats it.

I posted above before I saw your post.

Thank you so much!

I have been defeated by my derbesia at this point. I have not tried elevating my mag level yet. I can keep it under control, but if I get lazy it comes back and will overtake quite a territory. For me it takes a least weekly maintenance. AlgaeFix did not have much effect on it. :(

One thing I have noticed about derbesia is that most healthy coral can keep it away a very short distance. Some coral (mushroom & cabbage coral) keep the derbesia away on large rocks. Therefore I assume some toxin that is commonly produced by coral will control derbesia. The problem is which chemical is doing it and how toxic is it to other inhabitants.

Perhaps I should try placing mushroom & cabbage coral throughout my tank. :lol:

Perhaps this is why some hobbyists can control derbesia in their tanks, if they have the right coral on their rocks, then maintenance would be much easier. Biological control at its finest. :D

The Tech- M "M-bomb" worked well. For a while. Then the bryopsis came back.

I didn't eradicate it. I didn't have enough left to do the job again, only a half-dose, which only half worked.


I had some surprising success with very aggressive Vitamin C dosing (1/2 tsp 3X a day, 45g water volume in the system at the time) but the buffer agent in the VC drove my alk up to 15 in under a week, so I had to halt. My goal was to drive phosphate as low as possible, and it may have worked, or the VC may have actually caused some problems directly for the bryopsis. Either way, stuff started dying in droves, but when I cut back the dosing (for fear of alk-overage) the bryo just came back.


This stuff just keeps coming and I'm getting madder. My goal is to get the SPS growth in the tank high enough that I have a lot of alk consumption, so that I can return to VC dosing heavy.


Until then I'm using sucrose and VC as my dosing regimen, keeps phosphates low (according to the seachem kit) but the bryo keeps growing.




I am very close to setting up a small tank with some low-cost SPS and soft corals, and a big rock covered in bryopsis, and start a copper sulfate test to see if very low, very controlled, very well monitored concentrations will do the trick. Tech M used to list copper in it's "ingredient" list and it's been suspected a time or two.

Any suggestions for what test kit would be best, and what level to shoot for?

FWIW, I just treated a patch of bryopsis that is totally engulfing a frag of zoanthids. I took about 1/4 pint of tank water, added in 1/8 tsp of buffered Sodium Ascorbate and soaked them (zoanthids and all) in this solution for 20 minutes. The zoas closed up, but these are a particularly tough variety, so I'm hoping they pull through (if not, I have lots more where they came from, lol).


I'm hoping to see by this somewhat pitiful experiment if the VC has any affect on bryopsis in high concentrations, and what happens to the coral.

I base this only on the anecdotal even described in my post above.

At this point I'm about to order some Purple Up, an Eco-aqualizer, a Sham-wow, and maybe some concentrated snake oil. Maybe dosing all at once and scrubbing the rocks with the Sham-wow will help me lose weight, kill the bryopsis, and provide $5K a month in work-at-home income.

FWIW, I just treated a patch of bryopsis that is totally engulfing a frag of zoanthids. I took about 1/4 pint of tank water, added in 1/8 tsp of buffered Sodium Ascorbate and soaked them (zoanthids and all) in this solution for 20 minutes. The zoas closed up, but these are a particularly tough variety, so I'm hoping they pull through (if not, I have lots more where they came from, lol).


I'm hoping to see by this somewhat pitiful experiment if the VC has any affect on bryopsis in high concentrations, and what happens to the coral.

I base this only on the anecdotal even described in my post above.

At this point I'm about to order some Purple Up, an Eco-aqualizer, a Sham-wow, and maybe some concentrated snake oil. Maybe dosing all at once and scrubbing the rocks with the Sham-wow will help me lose weight, kill the bryopsis, and provide $5K a month in work-at-home income.

RedfishSC if you use non buffered VC then you can control the alk and dose as much as you want....

I thought about that, and may try, but sodium ascorbate has a pH of around 4, if I'm not mistaken, and I don't know what risks I'd be taking with a pH crash by dosing enough to take effect.

It's something to consider, but I have already had (possible) success with the buffered stuff, so maybe mixing them half-n-half will get me in the right balance.


I'll watch the frag I "C-bombed" earlier. The zoas are open like normal now. No real change in the bryopsis at this point other than some of the fronds having dark spots on them, but I don't know if that's something that's been there all alone or if it's actually something "changed".

I'm almost positive that you can add Baked Baking Soda to counteract the low PH. This way you can add enough to counteract the PH without driving your alk through the roof...

Adding baking soda is adding alkalinity, which would be what I'm trying to avoid. The buffered vitamin C probably uses either baking soda, or soda ash (ie, sodium bicarbonate or sodium carbonate) as the buffer.

Aside from that, baking soda actually will only allow a pH of around 7.6 if I'm not mistaken since it has a lot of carbon dioxide in it.

I had both a break out of bryopsis and despersia in a new 95 gallon that I had setup this past summer. The bryopsis likely came from the fact that it was a used tank (this stuff is tough!!). I believe the despersia came from me switching salt mixes and had used it in making water for this tank.

Anyways, I used the Kent TechM trick to kill bryopsis. I maintained mg levels of about 1700 for a month. After about 3 weeks and all the brypsis was dead, I started dosing AF as I had read a thread in another forum that it worked on his despersia. My mg was still around 1700 and I saw an immediate reaction from my HA to AF after about 4 or so doses.

My belief is that a combination of the 2 does seem to kill the stuff. Me raising my mag to 1700 for almost a month using Kent TechM did nothing to the despersia. It only killed the bryopsis. It wasn't until I started AF was I able to eradicate the despersia.

My 65 gallon tank that I have upstairs on the other hand also had despersia (no bryopsis). Using only AF, I haven't been able to kill it. I have been slowly raising my mag and weekly 20% water changes have I slowly started been getting a hold on it.

My gut feeling is that it takes both products to kill despersia but that's only based on my experience from my 2 tanks so please take it FWIW.

Is despersia a "derbesia" typo, or is it a different strand of algae? I have seen a few folks mentioning "despersia" and I have never heard of it.





I'm not sure how switching salt mixes can introduce an algae strain....???


Not a bad idea at all. I'd be watching the corals very closely though just in case the double-whammy didn't cause them undue stress.

Sp. Derbesia. :lol:

I hadn't thought about using AF & raising the mag. level. Certainly something as a last resort & removing anything valuable. It's worth a try. Let us know how it works for you. ;)

Interested in the Vit C. procedure too. :)

I've been thinking about trying to raise the copper level in my tank. The problem is there is no adequate test kit that I am aware of. Guessing at your tank copper level can be off enough, since the level you may want to try is very close to killing things. I have only seen copper toxicity to algae noted in a few research papers. Haven't seen anything for derbesia. The papers I have read show quite a wide variance in copper toxicity to algae. Some are quite low, while others can be too high for use in a reef aquarium. If I could find a reliable copper test kit for the range we are looking at I would give it a try. The only other way of using copper I can think of would be to add small doses & watch the results. Keep increasing the amount you add in small amounts but spaced far enough apart to allow the copper level to return close to normal. I would remove all valuable shirmp and use a few cheap shrimp as a monitor. :D

Maybe use a polyfilter between dosages to help brings things back to normal copper levels. ;)

Talk about playing with fire. :lol:

I have been giving some thought about using selected corals in my tank as biological control for my derbesia problem. The left side of my rock pile has little derbesia on it. The small cheap purple mushrooms seem to do a good job. I have quite a few of these mushroom now. I was thinking about placing them on some heavily infested derbesia areas and see what kind of results I get. The derbesia does not grow on my sand. It does grow on the glass, but that is easy to control. Any thoughts about how to best experiment with this method? :)

FWIW, These purple mushrooms seem to keep cyano at bay also. ;)

I have heard they are pretty hot (toxic). :lol:

After you told me this yesterday I noticed something. My liverock is in 3 columns in my tank. All 3 have this pest on them except the bottom of one. That one has red mushrooms on it. I will move some closer to other patches of derbesia to see what happens.

Keep us posted. I am interested. :)

Yeah some glass shrimp would be a good test, maybe some snails. I'd definitely throw some cheap coral in there like GSP or anthelia cuttings, perhaps some cheap SPS like bird's nest or red monti.


Salifert makes a copper kit, I think, but I don't know that it reads a range low enough. I've never used it.

I really want to test this out on bryopsis but I do not have room in my puny apartment for a small setup to be done. We have a 1 yr old son, so I can't just put it anywhere...



FWIW, my opinion is this: if the algae will eventually overtake the tank, I'd rather remove what is unadulterated by the algae and risk killing the rest, than let the algae win. PBITAWA!

Grind a few of them up in a blender and dose some mushroom slush? Perhaps directly squirt the goo onto the derbesia? Not very practical but if we knew what allelopathic compounds were in a mushroom... maybe it's a start....


I have noticed that bryopsis in my tank wont' grow in a live SPS, only dead. If I could only get my tank coated with cactus pavona and encrusting monti :D

I would be a concerned about the toxicity of the ground up mushrooms if you put enough of them in there. :D

I have been watching this thread and admittedly, have basically no experience with marine algae yet, except for (the nearly impossible to eradicate) Lobophora. I've only had a reef tank for 9 mo's, so read with grains of salt.

But, given what I know about copper toxicity, I would only try this in a small test tank with a Derbesia covered rock; of course you would do it that way anyway. ;)

I know this forum kind of panned the use of Seachem's Excel (which contains some aldehyde which may or may not be toxic), but if it were me, I would try this first (also in a test tank only). I have many years of planted tank experience and frequently use Excel to control FW green hair algae of various types and it usually works. FW tank people use more than the recommended amount to do this, sometimes 2x the rec. dose. However, one has to be very careful at these doses since it can kill FW shrimp (usually the fish seem unaffected IME). Bottom line, if I had Derbesia that I couldn't control any other way, I would experiment with Excel in a separate tank. It's a cheap fix if it works; I have no idea if it would work on SW algae, but it might. By the way, Excel is sold to the FW planted tank community as a carbon source to help grow the plants. Adding CO2 works better, but Excel can be used for low-carbon using systems. However, its algaecidal properties seem unrelated to its use as a carbon source. In other words, we don't think the higher plants are just outcompeting the algae with the addition of Excel.

Correct me if I am wrong. :)

The Seachem's Excel is a strong oxidizer, which would destroy cell membranes of many micro-organisms & coral epidermal cells. Possibly AF can do this too since it brakes holes into algae cell membranes but I am under the assumption that it does not do as much damage to coral membranes since there have been few negative effects. Once coral epidermal cell membranes are destroyed, then this leaves the symbiotic algae exposed to more oxidative damages. Then this would lead to bleaching of coral.

Fish have a slime layer protecting their epidermis from the oxidants. I would be very concerned about the effects of Seachem's Excel on coral FWIW. In fresh water aquariums you are dealing with advanced plants which have thicker more complicated epidermal layers than do coral and macroalgae.

I have emailed Seachem to double check this; you could be right Cliff. I'll let you know what they say.

Thanks, Please do. ;)

I can't explain it. I tried Red Sea and a month later I'm fighting my first case of HA. I only used the one bucket and it was the only thing that had changed. I've heard other people here in Atlanta having similar issues with that salt. Maybe it's something combined in our water here. Not sure.