Cyano help! (raising phosphates)

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Having some cyano issues as you can somewhat see in the photo. It’s been slowly getting worse over the past couple weeks and I finally went to my LFS to get it Hanna tested as my API phosphate test simply wasn’t telling me anything. It turns out my phosphates have bottomed out to ZERO and my nitrates are also low at 2.7. I’m planning on drastically increasing feeding to try and bump those up off of the floor but I also had my Alk tested which came out to be 7.7 which is also a bit low. My plan for raising that was going to be just increasing water changes to replenish it as I’m using instant ocean reef crystals. However doing so would dilute what little nitrates and phosphates I’m adding to the tank via overfeeding. Sorry for the rambling explanation but any advice from the experts?
20260907_171819_C6CE2100-0DC1-4784-B734-CDAD85C3476C.png
 
20260907_172052_AF66FF98-1194-44D3-8FB7-541BD0EB8061.png

Here’s a better look at the cyano. Or at least what I think is cyano
 
I would do water changes if your trying to increase nutrients/nunbers. Focus on the Alk using whatever additive you prefer. Increasing feeding is good. Dry food is higher in phosphates than fresh/frozen.
 
Is the macro algae growing? With a tank full of corals and macro algae, the nutrients are being taken from water showing low test results. But if the macro and corals are growing then there is enough nutrients in the water, no need at all to dose IMO. its the eye test vs the hobby test, eye test is better IMO.

You mean your lack of phosphate is what you believe is causing the cyano? I've not heard of that connection before.

I don't see any cyano in your tank, just what I would call a buildup of detritus and biofilm
 
It looks to me like possibly Dino’s especially with the trapped air bubbles, they happened to me when my nutrients bottomed out at well
 
1788818189512.png

That snot looks more like dinoflagellates to be honest. A microscope (200 - 400x magnification) would gives us enough information for a proper ID. This also matches with the biofilm on top of the water and the 0ppm phosphate readings.

Edit: TylerJaid beat me to it.
 
It looks to me like possibly Dino’s especially with the trapped air bubbles, they happened to me when my nutrients bottomed out at well
Definitely looks more like Dinos after comparing pictures. Thank you for the ID
 
Took a closer look at pics. I don’t see cyano exactly but did notice a film on the surface. Is the surface being skimmed?
Not at the moment as I have very small fish and the only fish guard I’ve found that fits on my tank is the innovative marine one which blocks surface skimming unfortunately.
 
It looks to me like possibly Dino’s especially with the trapped air bubbles, they happened to me when my nutrients bottomed out at well

I did a couple day blackout to knock them back than raised nutrients by dosing neo nitrate and phosphate and they went away! If you get sick of trying things it’s worth a shot! (Mine looked exactly like that and I believe it was ostreopsis, but that was never confirmed I was just losing some cuc)
 
It looks to me like possibly Dino’s especially with the trapped air bubbles, they happened to me when my nutrients bottomed out at well
Definitely looks more like Dinos after comparing pictures. Thank you for the ID
I did a couple day blackout to knock them back than raised nutrients by dosing neo nitrate and phosphate and they went away! If you get sick of trying things it’s worth a shot!
Sounds like solid advice, thank you. I’ll do some research into them and see what I can do.
 
Having some cyano issues as you can somewhat see in the photo. It’s been slowly getting worse over the past couple weeks and I finally went to my LFS to get it Hanna tested as my API phosphate test simply wasn’t telling me anything. It turns out my phosphates have bottomed out to ZERO and my nitrates are also low at 2.7. I’m planning on drastically increasing feeding to try and bump those up off of the floor but I also had my Alk tested which came out to be 7.7 which is also a bit low. My plan for raising that was going to be just increasing water changes to replenish it as I’m using instant ocean reef crystals. However doing so would dilute what little nitrates and phosphates I’m adding to the tank via overfeeding. Sorry for the rambling explanation but any advice from the experts?
20260907_171819_C6CE2100-0DC1-4784-B734-CDAD85C3476C.png
Pretty aquarium.

You did not mention the aquarium’s age. I will guess it is less than a year old based on the substrate and rock surfaces.

If phosphates have zeroed out, start dosing phosphate to get that level up, otherwise the algae are going to start dying off and that could feed a cyanobacteria bloom. Also pay attention to nitrate and trace element levels with macro algae growing in the aquarium. Depletion in either will lead to the same nuisance organism mess as depleted phosphate.

Good luck, it seems you detected the problem early.
 
Having some cyano issues as you can somewhat see in the photo. It’s been slowly getting worse over the past couple weeks and I finally went to my LFS to get it Hanna tested as my API phosphate test simply wasn’t telling me anything. It turns out my phosphates have bottomed out to ZERO and my nitrates are also low at 2.7. I’m planning on drastically increasing feeding to try and bump those up off of the floor but I also had my Alk tested which came out to be 7.7 which is also a bit low. My plan for raising that was going to be just increasing water changes to replenish it as I’m using instant ocean reef crystals. However doing so would dilute what little nitrates and phosphates I’m adding to the tank via overfeeding. Sorry for the rambling explanation but any advice from the experts?
20260907_171819_C6CE2100-0DC1-4784-B734-CDAD85C3476C.png

Yes my tank is only 5 months old. I did start it with well aged live rock from my LFS’s invertebrate system though. I’ll definitely start dosing phosphates and nitrates, what products would you recommend?
Would it be advisable to remove the macroalgae or at least some of it? I’m concerned that as pretty as they are, they have been sucking up too much phosphates and nitrates. I have another tank that isn’t having the same problem that I could put them in temporarily.
 
Having some cyano issues as you can somewhat see in the photo. It’s been slowly getting worse over the past couple weeks and I finally went to my LFS to get it Hanna tested as my API phosphate test simply wasn’t telling me anything. It turns out my phosphates have bottomed out to ZERO and my nitrates are also low at 2.7. I’m planning on drastically increasing feeding to try and bump those up off of the floor but I also had my Alk tested which came out to be 7.7 which is also a bit low. My plan for raising that was going to be just increasing water changes to replenish it as I’m using instant ocean reef crystals. However doing so would dilute what little nitrates and phosphates I’m adding to the tank via overfeeding. Sorry for the rambling explanation but any advice from the experts?
20260907_171819_C6CE2100-0DC1-4784-B734-CDAD85C3476C.png
Pretty aquarium.

You did not mention the aquarium’s age. I will guess it is less than a year old based on the substrate and rock surfaces.

If phosphates have zeroed out, start dosing phosphate to get that level up, otherwise the algae are going to start dying off and that could feed a cyanobacteria bloom. Also pay attention to nitrate and trace element levels with macro algae growing in the aquarium. Depletion in either will lead to the same nuisance organism mess as depleted phosphate.

Good luck, it seems you detected the problem early.
Yes my tank is only 5 months old. I did start it with well aged live rock from my LFS’s invertebrate system though. I’ll definitely start dosing phosphates and nitrates, what products would you recommend?
Would it be advisable to remove the macroalgae or at least some of it? I’m concerned that as pretty as they are, they have been sucking up too much phosphates and nitrates. I have another tank that isn’t having the same problem that I could put them in temporarily.
 

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