phosphates& algae

Opabinia

New Member
View Badges
Joined
Sep 20, 2025
Messages
16
Reaction score
4
Location
England
What state or country do you live in
United Kingdom
Rating - 0%
0   0   0
Hey all. currently dealing with an algae outbreak which im not even sure how to id (see photo below).
Now i know the cause is probably my negative phosphates, but what is the best way to increase them? ive turned my skimmer off as ive heard that helps but this algae is seriously annoying me as it coats my sandbed & my glass daily. I see some on the rock but it may also just be rock doing its weird thing. It isnt stringy (as of now) but i do see bubbles under the sand if thats related.
Ad info: tanks been up and running 4 months HOWEVER it is a move from a smaller tank i had running, with all the rock coming over from the old tank.
Is this just a weird ugly phase or something evil 🤔
20260901_121711 pm_DA808761-D45B-4B8A-BD1D-48E9F88CE6CD.png

Any id help would be greatly appreciated, along with any good phosphate increasing methods!
many thanks - reefer who cant catch a break with this tank👌
 
Best guess from a beginner: maybe diatoms?

For increasing Phosphates I dose Phosphates as a liquid, which i like best because I can estimate on how much I am raising phosphates. I did this daily until I could measure phosphates and then every week after measuring correct to 0.05 again. I had problems with mix of dinoflagalates and diatoms that disspeared on its own after dosing nitrate and phosphates and keeping it somewhat stable
 
Best guess from a beginner: maybe diatoms?

For increasing Phosphates I dose Phosphates as a liquid, which i like best because I can estimate on how much I am raising phosphates. I did this daily until I could measure phosphates and then every week after measuring correct to 0.05 again. I had problems with mix of dinoflagalates and diatoms that disspeared on its own after dosing nitrate and phosphates and keeping it somewhat stable
I did think maybe diatoms too, my tank isnt coral heavy or anything i dont know where my phosphates are going 🤣
thank you for your input 👌
 
My phosphate went into the dry rocks or sand - I guess. As it was not full of corals then as well. It’s been running for 1 1/2 year and I still have to dose phosphates sometimes, because now I have more corals and not enough fish. So every tank might be different. Do you work with RODI water to keep out silicates during water changes ? Diatoms should disappear when silicate is all metabolized and you do not add any new.
 
4 month old tank, so it's just part of the ugly phase.

Keep the skimmer running you want it for gas exchange.

While there is growth there is enough phosphate, but if you want to get them to detectable levels you can use the following DIY recipe: https://www.reef2reef.com/threads/diy-phosphate-dosing-recipe.1109919/

Many would suggest overfeeding/ghost feeding but this increases nutrients very unreliably and increases multiple things at once, so it's probably not what you want right now.

Exact identification usually requires a microscope, but I assume it's either diatoms or dinoflagellates. Both of which are fine in a 4 month old tank even if they aren't welcome in established tanks.
 
My phosphate went into the dry rocks or sand - I guess. As it was not full of corals then as well. It’s been running for 1 1/2 year and I still have to dose phosphates sometimes, because now I have more corals and not enough fish. So every tank might be different. Do you work with RODI water to keep out silicates during water changes ? Diatoms should disappear when silicate is all metabolized and you do not add any new.
Yes i only use RODI that i get from a local reef shop, never caused problems in the old tank so i assume this is just gonna be a phase 😭
 
4 month old tank, so it's just part of the ugly phase.

Keep the skimmer running you want it for gas exchange.

While there is growth there is enough phosphate, but if you want to get them to detectable levels you can use the following DIY recipe: https://www.reef2reef.com/threads/diy-phosphate-dosing-recipe.1109919/

Many would suggest overfeeding/ghost feeding but this increases nutrients very unreliably and increases multiple things at once, so it's probably not what you want right now.

Exact identification usually requires a microscope, but I assume it's either diatoms or dinoflagellates. Both of which are fine in a 4 month old tank even if they aren't welcome in established tanks.
I have been feeding a bit extra for the fish that came along from the old tank while keeping close eye on all tests, wont be able to feed extra now though as 3 fish have gone into qt following flukes/ich. thank you for your input 👌
 
How is the flow along the sandbed? It looks like a buildup of muck to me, detritus has settled and created a mat and algae is starting to grow on it.
 

TOP 10 Trending Threads

WHICH AREA OF REEFKEEPING MOST NEEDS A GENUINE BREAKTHROUGH?

  • Lighting

    Votes: 1 2.6%
  • Pumps and water flow

    Votes: 1 2.6%
  • Water testing and monitoring

    Votes: 14 35.9%
  • Controllers, apps, and device compatibility

    Votes: 5 12.8%
  • Filtration and nutrient export

    Votes: 1 2.6%
  • Automatic feeding

    Votes: 5 12.8%
  • Leak prevention and tank safety

    Votes: 5 12.8%
  • Equipment reliability and repairability

    Votes: 4 10.3%
  • Other (leave a comment in the thread)

    Votes: 3 7.7%
Back
Top
Home
Post thread…
Market
What's new