Jamie's Dinoflagellate Journey

[Jamie9]

Ok, so, like many folks on this board, I've got myself some dinoflagellates. What I find a bit frustrating, is that while there's many people discussing a plan of action out there, there's very few cases where people follow up with regular updates as to what worked and what didn't. Nor are there a lot of photos. Some of the threads I can link to a tank thread and see if things worked out or not. A lot of the original posters haven't been online for years, so the assumption there is maybe it didn't work out so well. Anyway, I'm going to do my best to document it all from start (a couple weeks ago for me) to finish.

TDLR: Physical removal has been the most successful thing for me. Get a canister filter, start it running, turkey baste all the dinos then get in there with a toothbrush and scrub what's still hanging on. Repeat until the tank looks good...and be ready to do it again as needed.

If you want complete details on my tank setup and history, I encourage you to have a look at my tank build thread. But, for the quick version, I've got an IM 40 gallon AIO Nuvo (cube). It's been just a little over two months since my cycle finished and I first added fish, so I'm definitely working with a young tank in the ugly stage now. That said, nothing I read suggests that dinos will just go away on their own if I do nothing. I started the tank with dry rock (about 30 pounds) and 5 pounds of TBS premium live rock. Plus 20 pounds of "dead" sand. If I were to do it again, I'd just go with all live rock, but too late for that now!

Here is my starting point for all this. It's not terrible, but the dinos are starting to irritate some of my corals, especially the gorgonians, so I don't want to just wait and hope things get better. As it stands now, things have been getting slowly worse from basically nothing at the end of December to noticeable daily spread now.



I've got potentially a couple kinds of dinos going on, which I will get into below. I'm going to try to break things into multiple posts to keep it manageable. (Side note, my nutrients never bottomed out, and in addition to everything below, I intend to keep them that way, and as constant as possible. Usually I'm around 10 ppm nitrates and 0,10 phosphate, I test at least once a week, or when making changes every day or two).

 

[Jamie9]

Microscope

So, first things first with identifying dinos was getting myself a microscope. I first tried a $30 cheap one off Amazon and it was woefully inadequate...basically just a camera with digital zoom...that didn't work.

I decided to just go for something nicer, which I can also use for work sometimes, and got a Tomlov DM602 for about $200. It took some practice, but once I got used to it, I can get some decent images off of slides, which I'll show below.

It came with a light from below slide holder which is sort of crucial to what we need. I originally tried using the top-down lights and that was a no-go. So, if you get one, use this thing:

 

[Jamie9]

Sample 1

The first sample was about a 2" long bit of mucus that I pulled off one of my Gorgonians. Here's what it looked like in the tank:

And here it is under the scope:

I believe what I'm looking at here is Ostreopsis. Which, isn't the worst news, as it seems like that is what people have the most luck getting rid of.

 

[Jamie9]

Samples 2 and 3

The next couple samples I got from the more stringy bits that were growing on my sand, on the dry rock, and on the back wall of the tank, like what you see hanging off this toadstool:

These samples were a little less clear cut:

This looks to me like there's a bunch of things going on. A few Ostreopsis perhaps, some algae mixed in, but then a lot of smaller guys that could be small cell Amphidinium or could be Chrysophytes? I don't really know and would love any input anyone has. Unfortunately this is as close a zoom as I can get, they are quite small.

 

[Jamie9]

Lighting

The first thing I've done is over a few days knock a couple hours of high white light off my schedule. I've got a single Kessil A360XE that I'd been running most of the day at 65% and pretty white.

I've now got it set to ramp slowly to 65% for two hours in the morning, then I stay at 65% and very white for 5 hours, then ramp down to nothing over 3 hours. That's down a couple hours from what I was running a few days ago.

I don't intend to do a blackout during this treatment unless all else fails, but I am good with lowering my lighting as long as my corals remain happy.

 

[Jamie9]

UV Sterilizer

I started running an 11 watt AuqaShield UV sterilizer about a week ago. It's a model that drops into the AIO compartment. I have no control over the flow that goes through it...but I've got it going 24/7 for now. When I start dosing bacteria I'll likely turn it off for 4 hours after dosing.

I realize this isn't as ideal as doing an oversize UV where I can dial the flow...but for now this is within my budget and easy to use. I don't think I'd look at something beefier unless everything else fails.

 

[Jamie9]

Copepods

I started a Chaeto refugium in one of my AIO slots. It's currently getting lighting for 8 hours overnight. I'm hoping it'll be helpful in stabilizing nutrients and out competing algae's that I don't want...but for now my main goal is a safe place for copepods to live. I put one jar of "Poseidon't Feast" in the refugium to hopefully get a population started there. That is Tigripous and Tisbe copepods. I put a second jar directly into my display. I'm dosing 10 mL per day of OceanMagik phyto to feed them. (All these I got from Algaebarn).

I wouldn't say I've noticed an increase in copepods in my tank yet, but it's only been 4 days since I started.

 

[Jamie9]

Hydrogen Peroxide

Dosing hydrogen peroxide has seemed to help other people with dinos in the past. I don't have a really satisfying answer yet as to why that is...but I'm also not seeing many cases where it seemed to do anything bad. As of today (1/18/2026) I'm starting to dose 3 or 4mL per day of H2O2 (3% solution off the shelf at the drug store) into the display.

 

[Jamie9]

Diatoms & Silicate

One thing that I noticed while looking through my microscope, is I had hardly any diatoms. There were a few in there, but really a tiny amount compared to the dinos and other things.

Many people in the past have had success defeating dinos by dosing silicate and boosting the diatoms...then letting the diatoms die off.

I'm not dosing any silicate yet, but I've got a test kit on the way to see what my silicate levels are to begin with. It's a new tank with a lot of dry rock and sand...so I might already have a bunch of silicate in there. If it turns out that is zeroed out...I'll potentially look at dosing silicate to boost the diatoms.

Here's a very helpful post by Miami (RIP) that lays out suggested dosing, which I'll use if testing indicates I need it.

Update:

On 1/19/26 tested for silicate (using a Seachem kit). The test result was < 1mg/L...essentially zero silicates, which explains why I'm not seeing many diatoms in my slides. The earliest I could get some silicate shipped was next week 1/28, so I'll retest then and possibly dose at that time.

On 1/22/26 the sodium silicate (41%) arrived and I dosed about 1ppm (0.7 grams for 40 gallons). I’ll do this once per week.

 

[Jamie9]

Aquaforest Life Source

This is another product people have had luck with. It's essentially some mud from the Ocean in Fiji, dosed to increase biodiversity in the tank. I've seen a lot of positive reviews, not much negative in recent times. Will it magically fix my dinos? No, I don't think so. But, I'm a fan of encouraging a more diverse biome that can outcompete the dinos...because I don't want to wipe out the dinos and then just have them come back. So, I'm going to give this a try, I've got a package coming next week.

Update 1/23/2026: My AF Life Source arrived in the mail today, so I'm going to dose it in the evening when the lights are off. The package says 5mL (1 teaspoon) for a 50 gallon tank. Mine is 40 so I'm doing about a teaspoon, mixed into a bit of RODI water. I'm also going to stick a strong magnet on the bottom of my mixing container as some have noted there's some magnetic particles that could possibly damage pumps (none confirmed but it sort of makes sense and I have a magnet, so why not).

Bacteria Boost

More along the lines of...it shouldn't hurt and some people have had good experiences...I'm going to start dosing MicroBacter 7. I don't want to tank my nutrients, so I'm going to start with 1 mL every other day, with the UV turned off for 4 hours. So, what I'll likely do is wait for the lights to come on for the day, shut the UV down for 4 hours and dose my phyto and Microbacter 7 then.

Update: I started dosing 1 mL MicroBacter 7 every other day, beginning 1/19/2026.

 

[Jamie9]

The Plan

Ok, so to break this all down. My plan looks like this:

1) Daily scrape the tank walls and give the rocks a bit of a scrub with a toothbrush to try to filter some of this out. Change my filter floss.
2) Run activated carbon to hopefully reduce any toxic stuff that I'm stirring up.
3) During the scrape down a couple times a week, I'll filter about 5 gallons through a 5 micron filter sock and then put the water back in the tank minus the gunk.
4) 10% water change weekly where I vacuum the sand bed a bit.
5) Dose phyto daily 10 mL to encourage copepod growth
6) Does hydrogen peroxide daily 3-4 mL
7) Dose Microbacter 7 every other day
8) Dose AF Life Source once per week
9) Consider dosing silicates pending test results
10) Run UV sterilizer
11) Keep nutrients in check throughout all this, meaning no double 0's, but also not causing spikes.

If I wind up with a diatom bloom, I'll probably pause some of these items a bit and just let them run their course. Any negative changes to fish or coral and I'll pull back as well.

This all seems like a lot...but really none of them should be anything that can disturb my tank balance...I hope.

 

[Kooma]

Thanks for putting this together! I’ve had a few blooms in the past, usually no big deal but the last lot me about 80% of my corals. It’s clearing up now, the only change I’ve made is dosing neonitro, my nutrients bottomed out which caused it.

 

[Jamie9]

Thanks for putting this together! I’ve had a few blooms in the past, usually no big deal but the last lot me about 80% of my corals. It’s clearing up now, the only change I’ve made is dosing neonitro, my nutrients bottomed out which caused it.

Yeah I should edit in the top somewhere...my nutrients never actually bottomed out, which is why I'm a bit confused to be in this boat in the first place!

 

[Jamie9]

Double post

 

[DexterKarin]

The Plan

Ok, so to break this all down. My plan looks like this:

1) Daily scrape the tank walls and give the rocks a bit of a scrub with a toothbrush to try to filter some of this out. Change my filter floss.
2) Run activated carbon to hopefully reduce any toxic stuff that I'm stirring up.
3) During the scrape down a couple times a week, I'll filter about 5 gallons through a 5 micron filter sock and then put the water back in the tank minus the gunk.
4) 10% water change weekly where I vacuum the sand bed a bit.
5) Dose phyto daily 10 mL to encourage copepod growth
6) Does hydrogen peroxide daily 3-4 mL
7) Dose Microbacter 7 every other day
8) Dose AF Life Source once per week
9) Consider dosing silicates pending test results
10) Run UV sterilizer
11) Keep nutrients in check throughout all this, meaning no double 0's, but also not causing spikes.

If I wind up with a diatom bloom, I'll probably pause some of these items a bit and just let them run their course. Any negative changes to fish or coral and I'll pull back as well.

This all seems like a lot...but really none of them should be anything that can disturb my tank balance...I hope.

I'm one of those that did not respond back about the results of my efforts. I have an IM30Long. I believe that I did not have a terrible outbreak of ostreopsis. I did have 0 nitrates and like you, in the microscope not many diatoms. My sand has always been quite clean. I do have some hair algae. But did all the reading as you have but a slightly different plan evolved. I did everything you did with the following exceptions and clarifications.

1. I did not scrape anything. Something I read said that the diatoms need green film algae that grows on glass. I also did no waterchanges for 3 weeks and then started with 1 gallon until today... 5 weeks later did a 3 gallon change. If no visible dinos, I'm going back to 3 gallons but every 2 weeks.
2. I did the peroxide treatment every night for 7 days. I really think this was effective. But corals didn't love it.
3. I turned off white light and only ran blues for 7 days till I read that it doesn't matter. I did reduce the photo period for 3 weeks to 5 hours.
4. I used microbater 7 or Dr. Tims Ecobalance once a day as well as phyto.
5. I added copopods and amphipods
6. Ran a green killing machine UV in the display but it is known not to be that great. Got the IM uv for the AIO. Seemed more powerful but as you said, was not in the display. I ran initially 24/7 and then reduced it to only nighttime probably a total of 4 weeks.
7. I started with a weekly doses of AF Lifeforce and silicates (3 drops). Again the reading led to this. And at least some of my samples have way more diatoms now. I wonder if I had a low diatom system. I did not test silicates.
8. One other thing I did was to cut a 4x4 piece of floss and connect it to a nori clip in a high flow area at night. This does take up at least ostreopsis and helps you gage how you are doing. Some people report super dark floss in the morning. Mine was never terrible but I could squeeze it out and test for the dinos with the microscope. I would rinse off and reuse the floss.

I fully admit that this approach was a bit haphazard because you the reading will drive you nuts after awhile with all the conflicting info. BUT, I no longer have visible dinos. I don't know if this is helpful but after 5 weeks, I'm going back to normal functioning which now will include nitrate dosing and AF lifeforce and silicate dosing. I just have a low nitrate system.

The one other thing is that the microscope was a blast and like you, want a better one now as there is a whole new world at that level.

Best to you. One last thing, at first I freaked out with the dinos, then I sat myself down and said, look at, this is reefing and it can be really interesting. I chilled after that.

 

[Jamie9]

Update 1/20/26

Ok, it's only been a couple days, and hard to say anything for sure, but it looks to me like things are pretty significantly improved. There's still dinos, but I've gone from things rapidly getting worse day over day to things appearing better. I know it's hard to tell from a video, but here's one anyway:



So far what I've done:

- Scrubbed the rocks once pretty thoroughly with a toothbrush and let the water filter normally.
- Swapped out my filter floss daily. These have been getting quite nasty overnight.
- Ran UV 24/7
- Dosed 10 mL phyto per day to try to encourage my copepod population. I can't say I'm seeing a lot of copepods...but I'm also not looking at night.
- Reduced my full lighting period to 5 hours, with 2 hour ramp on either side. (It was 2-7-2 before)
- Dosing 3 mL hydrogen peroxide per day
- Dosed 1 mL Microbacter 7 (I'm sure that's not doing anything yet, but just getting started on alternate day dosing)

Things I haven't done yet:

- Dosing silicate. I got a test kit and measured basically 0, but I don't have what I need to dose yet...and if the dinos go away in the next week before it arrives I doubt I'll use it.
- Dosing Aquaforest Life Source...it hasn't arrived yet. I plan to use it when it comes whether or not the dinos are still around.
- Micron filter/polishing. If things get worse, I might think about picking up a polishing filter to run overnight to really suck out anything in the water column. For now things are already improving so I don't want to spend the $60.

 

[ReefED!]

I had Dinos twice in my new 180g

First was SCA - small cell amphidium - I wiped them out with a kitchen sink approach of phyto dosing + plumbed UV + silicate dosing + dosing nitrate/phosphate + mb7

They were gone in about 10 days.

Then I made some errors and ended up with an Ostreopsis outbreak, which I did all of the above + plumbed another Aqua UV Advantage 15 watt UV directly into the DT - because most advice seems to indicate that UV is only effective against Ostreopsis when plumbed directly into the DT.

That case also went away in about 10 days.

My advice to anyone trying to get rid of Dinos is to do the same - hit it with everything. I don't know what really worked or what didn't, but I know I got rid of them in a short amount of time by doing the cocktail above.

 

[Jamie9]

Update 1/22/2026

I'd say since two days ago, things have gotten slightly worse. No improvement at least. My sodium silicate (41% concentration) arrived today. I mixed up as close to 1ppm as I could, mixed it well in two cups of tank water than dosed it in front of a powerhead. I'll do that once a week until I don't have any more dinos...and probably for a few weeks after that.

 

[ReefED!]

Update 1/22/2026

I'd say since two days ago, things have gotten slightly worse. No improvement at least. My sodium silicate (41% concentration) arrived today. I mixed up as close to 1ppm as I could, mixed it well in two cups of tank water than dosed it in front of a powerhead. I'll do that once a week until I don't have any more dinos...and probably for a few weeks after that.

Try mixing it with RO water first - I had a lot better success keeping it from covering everything in a precipitated snow.

 

[chapter7]

@Jamie9! Currently battling dinos myself and this was very helpful.