Diatoms

[dR3ws3r]

I've had a long standing fight with LCA Dinos in my main tank and have been dosing silicates for about 3 months+. I believe that over the last 2 or 3 weeks I finally have diatoms. They appear to form a film on top of the water as well as on the glass. There are still brown patches on the sand, but the difference in color (if it has changed) is hard to discern. I took a sample from the floating brown muck and looked at them under the scope. The long thin ones are what I expect to call diatoms, BUT there are a lot of blobs on there that aren't the spikey kind and I don't think they are dinos either. So I was wondering if they were another type of diatom?

Anyone have any input?

Sorry for the picture, but microscope, iphone and old eyes aren't always the best.

 

[Gumbies R Us]

Do you have photos of your tank?

 

[EnterName]

Diatoms can come in a variety of shapes. You can find a few in my microscopy thread:

Triangular, Rectangular, Oval, etc. they come in many shapes. If you can post a picture with a higher magnification, I might be able to tell you if there still are dinoflagellate cells. However, if there are only a few left, your problem appears to be solved for now.

Diatoms on the substrate look usually more like dust or simply a discoloration, while dinoflagellates are actually creating this brown slime that covers everything and traps air bubbles.

 

[PharmrJohn]

Just realize that, if they are diatoms, they use silicates to form their cell wall. Thus, diatoms tend to be self limiting as they use up this ingredient. As soon as silicates are not present in the tank, they live out their life cycle and pass to the great beyond.

 

[dR3ws3r]

Someone on another site seem pretty convinced it is a combination of diatoms and Chrysophytes. Not even sure what to do about Chrysophytes. There doesn’t seem to be a universal strategy.

I can probably get a better images. I’ll work on it

 

[dR3ws3r]

I cleaned yesterday during my water change, but here is a spot with “stuff”

 

[EnterName]

Someone on another site seem pretty convinced it is a combination of diatoms and Chrysophytes. Not even sure what to do about Chrysophytes. There doesn’t seem to be a universal strategy.

I can probably get a better images. I’ll work on it

Chrysophytes are quite rare and use silicates as well. Without silicate dosing, the level will drop and everything should normalize. I don't think you need to worry about them while you still have elevated silicate levels. I would consider them "part of the dino treatment".

If your tank is less than a year old it is fairly common to have dinos and I wouldn't worry too much about it if they came back, as long as they stay on surfaces where they don't irritate corals. If your tank is already well matured you might want to test other approaches to get rid of them.

With another microscope image at a slightly higher magnification we may be able to tell if there actually are chrysophytes.

 

[dR3ws3r]

I cannot get good images with my phone, but l tried

They particularly have the look of the bean split in half. My silicates are very low, but these "guys" are still hanging on. They continue to create a brown layer on the water surface. Anything I dip in the water comes out with this brown film on it.

My silicates from my last icp at of 6/26

I do not see any of the spikey diatom shapes or dino brown beans so far.

I am not sure what to do about the chrysophytes other than hope the lack of silicates kills them off.

Anyone have any idea what these might be?

 

[EnterName]

I cannot get good images with my phone, but l tried

These look like diatoms. They come in various shapes and sizes. Here for example is a quite common triangular-shaped diatom which appears frequently in reef tanks:

The following images are freshwater diatoms but the shape-diversity is very similar in saltwater. The ones without colors are just the "empty silica shells":

The last one is probably the shape we are looking at in your images.
​

Another R2R member posted even a quite rectangular one on my microscopy thread.