Major Algae Issue

An Alga Turf Scrubber (ATS).

While the images you just posted rather than the video do not look like dinoflagellates the algae growing on the rocks that appears slimy or snooty in appearance does look similar but without bubbles. It is the appearance of struggling corals and the demise of the snails and hermits that has me thinking this is an algae or bacteria that releases toxins.

Water changes in my opinion just feed dino.

Things to consider are water source, nitrates and phosphates.
Introduction of nutrients in the food source.
Could the rocks be leaching phosphates of after prolonged exposure to high levels in her tank?

If she has a sump or refugium could you use cheato or mangroves to export or out compete the algae for nutrients?

Has she tried any type of product like Algaefix?

The images look like she does not have a lot of corals, so I would be somewhat aggressive in looking at treating it either as an algae or dino.

I would also see if John at Reefcleaners can shed some light on the situation.

 

She has that but has since taken it offline because of the algae problem. I was going to suggest that but at the same time do like a 75 gallon water change and put fresh water in there. If you use the algaefix you have to do a 35% water change anyway. Her water source is my water and you have seen my tank.

 

I think it is a cyano species too. Not all cyano is red slime, there are thousands of cyano species out there. You usually can just get an id down a type of cyano. Red Slime covers more than just one species, some rarely form mats, some form very dense rubber red slime clumps that can be lifted out in a chunk etc... Yours looks like a Calothrix type of cyano. Calothrix is the name of a genus, but in the hobby it refers to brown slime cyanobacteria that have some filamentous features. That is pretty much what you have there. If it were a little longer or redder is would fall under "Lyngbya", but it usually isn't worth taking microscopic shots of the particular cyano to get an accurate species level identification.

 

The stuff on the rocks looks a lot like the bryopsis that I have in my tank. It's hard to tell from the quality of the video, but I'm 90% sure. Bryopsis doesn't have the feathery looking leaves until it really takes off. Initially it looks like gha, but grows in clumps and not as long.

I used Algaefix to get rid of what I thought was gha. All of the algae died off, except the bryopsis, which took off because of a lack of competition. I'm about 2-1/2 weeks in on 1,800 mag level, and it just starting to recede a bit. Cyano grows on the bryopsis when it fades.

The FOWLR also had it. The lights have been off on that tank for nearly three weeks, and a bunch of it is still holding on. It showed no sign of weakening for two solid weeks with no light. Just so you know what you may be up against.