Macroalgae die off help

[GothFishKeeper]

So I recently moved all my corals into my larger system finally, and turned my nano reef into a macroalgae tank that I’ll be putting dwarf seahorses in. I finished all the macro scaping last week and this was the final product which I’m really satisfied with

Pretty quickly the macros began getting microalgae growing on them, which I’ve tried remedying with occasionally just wiggling my finger on each one to shake it off. It works to an extent but once the seahorses are in there that could be risky to do, and of course it doesn’t get rid of it all. Now as of the last couple days some of the macros are actually starting to die. I don’t know if the microalgae is the whole issue, but I assume it’s at least part of it. I don’t believe it’s a nutrient issue because I’ve been dosing brightwell neonitro to consistently maintain 5ppm of nitrates. I’m wondering if for some of these species it may be a lighting or temp issue so I’m wondering if anyone has any info on specific requirements for any/all of them as I can’t find much info on most of them. Tank temp is 74°F as it will be a seahorse tank and the cooler temp will reduce infectious bacterial growth. The light I’m using is the Susanoo 10W macroalgae light from The Marine Plant Store, recommended to me by MosaicMacros. I’ve been running the light 12 hours on and 12 hours off.
Livestock for animals at the current moment are a harlequin shrimp (and his chocolate chip starfish), 6 peppermint shrimp and 3 berghia nudibranchs (to destroy any possible aiptasia long before seahorses go in), a blue porcelain crab, 8 nassarius vibex snails, 6 dwarf cerith snails, 12 zig zag periwinkle snails, and 12 button snails.

The species of macros in question in order from the most die off to the least die off are:

Spiny seaweed (Eucheuma isiforme), it really sucks to see this one dying so quickly because it’s my favorite out of all of them as yellow is my favorite color and it looks really good on the opposite side of the tank from the yellow finger gorgonian.

Succulent orange Gracilaria

Blue hypnea (some bunches doing better than others)

Pink feather

Pink Knobby Laurencia

Red bush gracilaria, aka pom pom

Red sea grapes

Carpeting Halimeda (Halimeda opuntia)

All other species in the tank seem to be doing well aside from having microalgae on them

Also if anyone has any tips as to how I can remove algae from the NPS gorgonians in here it would be greatly appreciated. They’re doing fine and eating still but there is algae starting to build up on them which I know isn’t good. I tried blowing them off with a large pipette but it just sent sand flying everywhere. I know high flow is ideal but it’s a macroalgae and seahorse tank so there aren’t any areas like that.


Thank you to anyone and everyone who read this whole thing regardless of if you have info to provide. I know I tend to over explain things, not only on here but in day to day life in general. It’s something I’ve always struggled with, so I appreciate it greatly when people are willing to listen and take in all the info I have. Any tips, info, or advice would be amazing to hear though if you have it, thank you!

 

[njmaddreefer]

I know you mention it’s not likely a nutrient issue, but what are your phosphates at?

 

[carol3]

I would like to know how it's going, did you figutr anything out? I haven't found macros especially easy, it seems to be one of those things where you plant different kinds and go with the types that do survive in your system.

 

[GothFishKeeper]

I would like to know how it's going, did you figutr anything out? I haven't found macros especially easy, it seems to be one of those things where you plant different kinds and go with the types that do survive in your system.

So the reason for the spike in nuisance algae I’m guessing was all the fresh surface area to inhabit. I did some research and it turns out that, just like rock or sand, macros are a surface that need to be properly colonized by the right micro organisms, otherwise the wrong ones will take up the space instead. That was also the reason (along with the large amount of new macros bottoming out nutrients) for a hefty dino outbreak that came about shortly after creating this thread, as seen here:

The solution for this was a 48 hour total blackout with the tank completely covered in cardboard, followed by installing a small UV sterilizer, and daily dosing of these three additives:

The first two obviously to restore nutrient levels, and the fritz monster 460 bacteria as competing micro organisms. The bacteria dosing does need to be followed by a few hours of having the UV turned off, but just a few was fine for me even though the bottle says to turn off UV for 48 hours after dosing. That was obviously not very productive. Also, using 2-3x the recommended dose of this bacteria ensured that, number one, anything killed by UV was accounted for, and two, that it was potent enough of a competitor for the nuisance algae and most of all dinos. A LFS near me recommended this bacteria specifically for battling dinos and it definitely was the right suggestion.

Now a month later, the tank looks like this:

Not only has macroalgae growth exploded, but also coralline algae growth has resumed despite not having blue light available, AND one of my mermaids fans even propagated! The two photos of the new plant are just a day apart:

Hopefully other people battling this issue find this update helpful, as this method of treatment has truly worked miracles for my tank!

 

[resortez]

Question. Where you performing water changes within that month of battling the algae to the final result???? Or any other type of maintenance performed during the protocol like removing or adding carbon, syphoning of sand, new filter pads, etc???? Thanks

 

[GothFishKeeper]

Question. Where you performing water changes within that month of battling the algae to the final result???? Or any other type of maintenance performed during the protocol like removing or adding carbon, syphoning of sand, new filter pads, etc???? Thanks

I typically do weekly 25% water changes on both of my tanks as a means of partially restoring calcium and alkalinity and regulating nutrients, but during the past month ive halted them on the macroalgae tank because i needed the nutrients to continue rising. That being said, the tank has been running for over a year now, so it’s well established. Also it is currently fallow, and the only animals in there are two gorgonian corals, two peppermint shrimp, a harlequin shrimp, and a porcelain crab, and cuc (just snails)… so an extremely low bioload. That combined with the incredibly high ratio of plants to animals, it maintained itself in the process. If you have a higher bioload in your tank and/or less macroalgae, it might be better to continue water changes, but maybe just do smaller ones.

Also I never siphon my sand, I let my cuc rotate it and if diatoms build up i just let it be until they’re eventually stirred up by the nassarius snails and conch. In my experience stirring up large portions of sand just leads to more problems than solutions.

Lastly, yes I still changed the blue filter pad at the top of the second chamber of this AIO system. The top is a filter pad and the bottom shelf is a bag of carbon which I didn’t worry about renewing during this time, but that’s just because I usually switch it every month and I had just done so right before this all started.