Help!! Algae, algae and more algae

Ok everybody - I need some help here. I am about 1/2 done quarantining my fish in an attempt to starve out parasites since we had a few fish die.

Over the last few weeks, I have started to see algae outbreaks of various kinds in my tank.

So first, I need some help identifying a few of these algae types.

Here is the first one:

I took a video of it too because sometimes it can be tough to see in pictures:



So the obvious question - what is that? It looks kind of like dino, but I don't see any of the bubbles that I would expect to see with dino? Or is it cyano? Red Turf Algae? Diatoms maybe?

Here is another picture of it growing on a rock (and I do see some bubbles on this rock as well):

Then there is this stuff growing in my overflow:

The overflow is the only place I am really seeing the picture above.

I am also getting a lot of an algae like film growing on the glass as well. I am having to scrape it off about every 3 days:

And finally, I have recently started to notice this film floating in my sump. I have never seen anything like this before (notice the fine layer of something on the surface):

We haven't been doing much feeding at all in the tank the last 6+ weeks because the fish are out of the tank during quarantine. My wife does feed the coral, but only once or twice a week. So it shouldn't be an over feeding issue.

We have a decent number of snails in the tank, and a handful of emerald and hermit crabs. Perhaps we need more?

I am running both GFO and Carbon in the tank. And I am also running a UV Sterilizer in the tank (although I don't think that would make a difference here). And I have a skimmer that is running as well.

My salinity last I checked was right around 1.024 (a little low I know). And the temperature is definitely higher than it should be (between 80-82 degrees). I have a chiller but it keeps blowing my fuse so I need to figure something out there.

Nitrite and Ammonia levels are near 0. Nitrate is at 3ppm. Alkalinity is a little low at 6dkh and calcium is a little low at 380ppm. Phosphates are showing 0ppm, but I have been told that test is basically useless since algae can absorb the phosphates.

High TDS perhaps contributing to the problem in by RODI water? I noticed they got a bit high when my RODI filters needed changing. That has since been corrected, but perhaps the TDS of the RODI water in the ATO before I changed the filters is contributing to this?

When we had the fish in the tank, we were doing about a 20% water change each week. Since there aren't fish in there anymore, I haven't done a water change in a few weeks. But I did notice these problems starting to happen even before we took this fish out?

I would like to try to fix the problem before we put the fish back in the tank in a few weeks but am not sure where to start, or even how to identify what these algaes are for sure!

I would like any feedback that anybody has!!!!

 

The tank is not too old. About 3 months. It was an upgrade from a 65 gallon tank. So the tank and sand are new. But we used the same rock, sump and some of the same water that was in the 65 gallon when we upgraded.

I definitely agree that there are excess nutrients, but my question is what could be feeding it? With no fish in the tank, we feed the coral very little. What else could potentially be causing the growth?

For lights, I have three AI Hydra 26 LEDs. The are set to run most of the day. They start their ramp up at 8am and gradually start ramping down at 5pm:

I do have a small CUC. Some nassarius snails and a couple of fighting conchs (although for some reason they seem to not live too long). Oh and a sand sifting star fish. And some crabs but they don't really seem to turn up the sand bed much. I do have a sand sifting gobi, however all the fish are out of the tank right now for about 6 more weeks. You think more flow? I have 3 power heads in there already but perhaps a need a couple more. There is quite a bit of flow in there, but maybe that spot isn't getting hit well?

 

Hey Bud. Great info! Thanks so much!

I have a few questions for you. My wife is suggesting we use Chemi-clean on the tank before we put the fish bank in (still have 6 more weeks to go before we can do that). Any thoughts on if this is beneficial or not?

Second - I don't know much about algae scrubbers. Obviously they grow algae. Am I understanding the concept correctly in that you grow the algae in the scrubber it will prevent the algae from growing elsewhere in the tank? What if I have chaeto growing in a refugium? Would that not work well together?

I see you have a few different kinds of the algae scrubber. What would you recommend for a 125 gallon tank with a 39 gallon sump?

 

I didn't see this by quickly glancing at your website - what is the price of the L2 unit? And what kind of availability do you have with it?