Low Po4 and Nitrate Bust still GHA

[FlameangelLover]

I don’t understand how I have low Po4 and nitrate and still get green hair algae? Can someone give me advice?

Po4 0.05-0.15max

Nitrate Undetectable

 

[Mr. Mojo Rising]

The algae consumes the available nitrate/phosphate faster than anything else in the system, IME its normal to see low nutrients when algae is thriving.

 

[FlameangelLover]

 

[FlameangelLover]

The algae consumes the available nitrate/phosphate faster than anything else in the system, IME its normal to see low nutrients when algae is thriving.

It doesn’t make sense why I have high nutrients I have 3 fish in a 40 gal and do weekly water changes and only feed frozen mysis

 

[Mr. Mojo Rising]

It doesn’t make sense why I have high nutrients I have 3 fish in a 40 gal and do weekly water changes and only feed frozen mysis

Dissolved organics, bad bacteria's, lack of algae grazers, and low flow all have a role in algae growth, its not just about the nitrate and phosphate level. If you can share more details on your system I'm sure folks can help. Type of filtration, how much you feed, how much water you change weekly, how old is the tank, using dry rocks or started with live rock? All this info helps us pinpoint the cause of the algae, pictures also help. Some amount of algae is very normal, it depends on the situation. Lets also identify the algae, make sure its indeed hair algae. What type of clean up crew and algae grazers do you have? Sometimes its as simple as increasing the algae grazers. Lots to consider but we can help you if you can share some info, thanks.

 

[JTP424]

I question if that is hair algae? Looks maybe bacterial?

 

[FlameangelLover]

I question if that is hair algae? Looks maybe bacterial?

I question as well if it’s hair algae . Any way I can find out?

 

[JTP424]

sample under a microscope and someone on here could confirm, if you can get some closer photos of it as well we may be able to identify.

 

[FlameangelLover]

It doesn’t make sense why I have high nutrients I have 3 fish in a 40 gal and do weekly water changes and only feed frozen mysis

Dissolved organics, bad bacteria's, lack of algae grazers, and low flow all have a role in algae growth, its not just about the nitrate and phosphate level. If you can share more details on your system I'm sure folks can help. Type of filtration, how much you feed, how much water you change weekly, how old is the tank, using dry rocks or started with live rock? All this info helps us pinpoint the cause of the algae, pictures also help. Some amount of algae is very normal, it depends on the situation. Lets also identify the algae, make sure its indeed hair algae. What type of clean up crew and algae grazers do you have? Sometimes its as simple as increasing the algae grazers. Lots to consider but we can help you if you can share some info, thanks.

Thanks Mojo

40 Gal breeder use HOB filter with carbon that I change every month and I do weekly 10% water changes so about a 5 gal bucket and I have two clowns and a red flame angel and 3 snails. And take is 1 year old and I have a HOB skimmer

 

[FlameangelLover]

sample under a microscope and someone on here could confirm, if you can get some closer photos of it as well we may be able to identify.

 

[Mr. Mojo Rising]

Ya sorry, I don't know what that is either. I'm sure someone can help identify that. good luck

 

[Gumbies R Us]

Tagging the rest of #reefsquad

 

[FlameangelLover]

Tagging the rest of #reefsquad

Please I need help bad!!!!

 

[Fish Styx]

That appears to be a heterotrophic bacterial bloom. Usually fueled by dissolved organics.

 

[TheNative192]

Please I need help bad!!!!

I ran into this exact issue before. It may not be GHA but its some type of Algae or Bacteria feeding on nutrients. One of the tricky things about green hair algae or nuisance algae is that when there’s a lot of it, it actually consumes a significant amount of nutrients. So it’s very common to test “low nutrients” while still having a tank full of algae. The algae is essentially masking the real nutrient load because it’s absorbing nutrients as fast as they’re produced.

That’s why you have to tackle both sides of the problem at the same time:

1. Reduce the nutrient input and availability
   • Cut back feeding slightly (if you’re overfeeding).
   • Run phosphate media like GFO (I personally use Rowaphos).
   • In more severe cases, some people use lanthanum chloride carefully.
   • Make sure export (skimmer, water changes, filtration) is optimized.
2. Aggressive manual removal
   Think of it like a garden. If you have 10 plants and 10 pounds of fertilizer, everything balances. But if you suddenly have 100 plants, that same 10 pounds disappears quickly. GHA or the nuisance algae/bacteria becomes the dominant “plant” in the system and soaks up everything available.
   Manually remove as much as you can — pull it, scrub it, siphon it out during water changes. The more biomass you physically remove, the more nutrients you’re permanently exporting from the system.

Adding clean-up crew like turbo snails or an urchin can definitely help, but most of them won’t touch long, established strands. They’re better at maintenance once you’ve knocked the bulk of it down manually.

Also, I’d be cautious about jumping straight to fluconazole which will kill GHA, not sure if that is what this is but yeah. It can work, but when the GHA dies off all at once, that mass breaks down and releases the nutrients it was holding right back into the system. If the underlying nutrient issue hasn’t been corrected, you can end up with another spike or just trade one algae problem for another. Chemical solutions don’t fix the root cause — they just remove the symptom.

Bottom line: don’t chase numbers alone. Remove the algae mass, control nutrient input, increase export, and over time the system will rebalance naturally.

 

[FlameangelLover]

That appears to be a heterotrophic bacterial bloom. Usually fueled by dissolved organics.

What do you do to fix it?

 

[FlameangelLover]

Please I need help bad!!!!

I ran into this exact issue before. It may not be GHA but its some type of Algae or Bacteria feeding on nutrients. One of the tricky things about green hair algae or nuisance algae is that when there’s a lot of it, it actually consumes a significant amount of nutrients. So it’s very common to test “low nutrients” while still having a tank full of algae. The algae is essentially masking the real nutrient load because it’s absorbing nutrients as fast as they’re produced.

That’s why you have to tackle both sides of the problem at the same time:

1. Reduce the nutrient input and availability
   • Cut back feeding slightly (if you’re overfeeding).
   • Run phosphate media like GFO (I personally use Rowaphos).
   • In more severe cases, some people use lanthanum chloride carefully.
   • Make sure export (skimmer, water changes, filtration) is optimized.
2. Aggressive manual removal
   Think of it like a garden. If you have 10 plants and 10 pounds of fertilizer, everything balances. But if you suddenly have 100 plants, that same 10 pounds disappears quickly. GHA or the nuisance algae/bacteria becomes the dominant “plant” in the system and soaks up everything available.
   Manually remove as much as you can — pull it, scrub it, siphon it out during water changes. The more biomass you physically remove, the more nutrients you’re permanently exporting from the system.

Adding clean-up crew like turbo snails or an urchin can definitely help, but most of them won’t touch long, established strands. They’re better at maintenance once you’ve knocked the bulk of it down manually.

Also, I’d be cautious about jumping straight to fluconazole which will kill GHA, not sure if that is what this is but yeah. It can work, but when the GHA dies off all at once, that mass breaks down and releases the nutrients it was holding right back into the system. If the underlying nutrient issue hasn’t been corrected, you can end up with another spike or just trade one algae problem for another. Chemical solutions don’t fix the root cause — they just remove the symptom.

Bottom line: don’t chase numbers alone. Remove the algae mass, control nutrient input, increase export, and over time the system will rebalance naturally.

Is feeding frozen mysis bad?

 

[sgdnycct]

I guess the first step is to confirm that it is GHA and not bacterial.

To me it looks like GHA. Theres a lot of variables involved but most likely over time nutrients got absorbed into rock and substrate. Once they stopped absorbing GHA will start sucking it as fast as it is produced or released into the water column.

The best thing to do is outcompete the GHA- this means you need a way to absorb nutrients (phos in particular ) before the GHA has a chance to do so. I use a refugium and macro algae. You can use phosphate absorbing material if you don’t have a fuge.

Constantly and gently remove GHA by hand, anything that gets loose you can pick out with a small net. You may get suggestions to scrub or use H2O2- I do not recommend this as it affects the biofilm on the rock.

I stress that first you feed what the fish need to be healthy and not hungry then control any over feeding (only saying this because people will probably start telling you to cut back on feeding). Nutrient management is separate and should balance the bio load.

Water changes, keep in mind, help reduce nutrients but not if the nutrients are already absorbed by rock, substrate and algae. Also, mathematically, water changes will only get you so far. Point is that water changes may not help much at this point. Where the water changes may help is to suck out some of the algae.

How often do you test your water? What test kits? Have you ever had any spikes? Is the protein skimmer working well/properly? Any sources of phosphate in the tank? Quality of the food? All these are good question to ask yourself and look into.

If it’s bacterial- that’s a different thing altogether and will leave it to someone who is experienced in that as I’ve never had it.

 

[Fish Fan]

Agreed, that looks bacterial, not green hair algae

 

[FlameangelLover]

Agreed, that looks bacterial, not green hair algae

If it is bacterial is there a different fix?