Need help identifying algae (Microscope images)

[Max Rackstraw]

Ive got a brown/green/red slime on my sandbed. Its only on the sandbed, the rocks are completely clear of it.

It does seem to disappear or get a lot less visible when the lights go out at night.

It clumps together on the sandbed like a mat. It doesnt blow off like dust.

I didnt used to clean the sandbed during water changes but recently i have started to (last two weeks). It has made a small difference on this algae, it doesn't seem to grow quite as fast now.

I do a 10% water change once every week, so clean the sandbed at the same time once per week.

Parameters:
2.5ppm nitrate
Temperature: 25c
Alk: 7.5dKH
Cal: 340ppm
Mag: 1290ppm
Tank size: 100L (22 gallons)
Lighting: Radion xr15 gen 6 on 40% 6hr lighting period (16500k spectrum)

(Alk, cal and mag are low at the moment since my coral has just started taking off and water changes are nolonger keeping up with demand so i have just started dosing although slowly at first)

I have attached some pictures under white light and some microscope images.

I think it's probably Dinos but i have not seen this one before. I do see a couple of the typical egg shaped dinos here and there, but a lot more of these guys under the scope.

Interested to see what these are.

 

[GSPClown94]

The microscope images look like some kind of diatom.

 

[Max Rackstraw]

The microscope images look like some kind of diatom.

Yeah i have seen a couple images that look similar but they are not really from very credible sources so i havent been able to verify what they are

 

[Max Rackstraw]

 

[Max Rackstraw]

Ive taken some more microscope images here. I can see a lot of those diatom looking things but importantly in some places theres a lot lf what i believe are dinos (those egg shaped ones)

 

[Max Rackstraw]

 

[Max Rackstraw]

These ones (the ones i think are diatoms) forming chains

 

[Max Rackstraw]

So to clarify, I have had this algae on the sandbed for a while. It has changed appearance multiple times but there has been some form of algae on the sandbed for over 2 years.

So what I am seeing here is A LOT of those diatoms. But also what appears to be either Amphdinium or Prorocentrum dinos. I think its the former but anyone more experienced is welcome to correct me!

Does this mean I should just let them do their thing? I know that encouraging the growth of diatoms to outcompete the dinos is a widely used strategy, and it appears that might already be happening?

 

[Justfebreezeit]

Any change for you on this issue?