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Algae growing on corals

1st reef

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Noticed a brown layer on the green cabbage. Glass turns brown within 5 days of cleaning. Nitrates are below 5ppm. Alk is at 8 more or less. I only top off with distilled since nitrates are very low. I haven't done a water change in 3 weeks. Live stock is Clow, ywg, pistol shrimp, turbo snail, 3 hermit crabs. 

What should I do? 

Continue what I'm doing?  Filtration is only filter floss. 





Pics were taken without blue light. 

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Before I start I am assuming you are new to the hobby? So first off how old is this tank? Second, you should be doing a water change way more frequently unless this tank has been established for a couple years. For your tank I would do a 1-2 gallon water change every week they help a lot. 1 product that I do suggest (with personal experience, helped me get rid of a lot of hair algae) is vibrant algae control and tank cleaning. It makes your water pretty clear if it is murky or cloudy and helps with algae control. If you do decide to use something like that then FOLLOW THE DIRECTIONS! A lot of people used it very impatiently and yes got rid of the algae but just to start getting this weird red film everywhere. Just be patient with it and it will work. Also I think you should get maybe a banded trochus snail or two and if your want to you should get either a conch or a couple of nassarius/super tongan snails. Also for filtration I would probably add some type of carbon I would suggest a chemi pure blue or elite and switching them biweekly.

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I was told on this site to only change water if nitrates are to high or if alk is too low. As for filtration, was told also that live rock and filter floss is all I need. 

Water is not murky at all. 

It's been running for 4 months. 

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Looks like you have hit the typical ugly stage in the hobby, i would just carry on doing what you have been doing. The tank will eventually get past this point. 

I dont subscribe to the regular water changes either myself but rely on testing parameters (for me nitrates and phosphates) so i think I am roughly 15-20% monthly 

Just keep the glass clean and change the floss when you notice it is nasty 

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I would suggest having the Power head on the right hand side, lower down with a slight point up to the surface, that will get the surface moving with vigor, and the force water down the walls to the sandbed... That will be some decent flow then. 👍🏼👍🏼

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  What are you phosphate levels at? Weekly water changes would be best as long as your tank is up. I ran a 5 gal for years and if I skipped a weekly I'd see algae pop up the next week. As others have mentioned, if you're tank is less than a year or even a year and a half old and you feed daily, expect algae (ugly stage) and don't do any major changes. 


  BRS TV did a YouTube video using only vibrant to treat different types of algae. It pretty much worked on all of them but it took multiple weeks to really show improvement. 


  From my experience and from doing my own research, heavy feeding with high phosphates and no way to regularly remove the waste is often the cause of algae blooms.  Try feeding 2-3 tx a week, weekly 10-20% water changes, and dose vibrant every other day.


  If vibrant is too expensive (cause it is) then try dosing something like fritz zyme 9 to boose beneficial bacteria every water changes. They're totally different types of microorganisms but you'll still be fighting through competition. Hope this helps. Good luck man. 


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I added 2 Trochus snails in my 10 gallon 2 days ago. I am wondering if I should have only gotten one for my tank.  They are looking like good cleaners so far doinge doing a really good job eating the crud off my Rocks.  Haven't spent a second on the glass since I put em in there.  


I did find one on the sand upside down this morning and returned him to the most crud looking rock where he started grazing again.


Astrea are on the glass and rock back and forth

Spiny star Turbo - all over tank.  Rock, glass, sand

Trochus - so far looking like only rocks but it's still new snail me.  May change over time.


Good addition to the tank.


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Get live phytoplankton and dose a little every day. It will consume the nutrients the nuisance algae is feeding on. It will also feed any copepods you might have living in the rocks and sand. The copepods will eat some of the algae and any detritus other clean up crew can’t get to. If you don’t have pods in your tank, get some live pods too. Beyond the bacteria nitrogen cycle, the next most important and overlooked cycle is the zooplankton and phytoplankton cycle which helps to maintain a solid base for your ecosystem. 

Also, it doesn’t look like you have a good amount of rock for the water volume you have. It will take a lot longer to establish a strong biome with less rock. 

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1 hour ago, 1st reef said:

It's only a 5 gallon. I figured the rock is enough. I added pods about 2 months ago. Should I add again? 

The phyto should help the pods continue to thrive while eating the nutrients that other algaes need to grow. If you’re still seeing pod activity in the tank, the phyto should be good enough. 

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12 minutes ago, 1st reef said:

I have zero phosphates. The brown algae happens when the pistol shrimp stirs up the substrate. Will add more pods today. 

DevilDuck is suggesting you dose to raise your Phosphates. 


I recently had nasty DINO issue with zero nitrates & Phos.  I got my nitrates up naturally from feeding / adding a fish.  Ended up havign to dose Phosphate vis Brightwell Neo Phos.  Very helpful with dinos if that is what you have.

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6 hours ago, 1st reef said:

How does raising phos help? Isn't it the point to have zero phos? 

This is a common misconception but It is actually incredibly dangerous to have 0 phos, all photosynthetic things in your tank need it to survive. 0 phosphate is also known to contribute to outbreaks of Dinoflagellates. which what looks like is starting to form in your tank. You want to maintain your phos level between 0.03 and 0.1, IMO anyway. I actually went through something extremely similar to what you may be experiencing at the moment, the early stages of Dinos. You can read through my thread attached below if you're interested. 


I would immediately try and get your phosphates above 0ppm. I would then try and get some sort of ID on the algae to confirm if they are indeed dinos. this can be done by taking a sample of the algae strands in your aquarium and placing it in a glass jar or container with about 1/2 cup of tank water. Screw on the lid and shake the jar vigorously, until the algae strand has broken up. Then place the jar under your tank light for about 30-40min. if the algae has reformed into long snotty strands, you have Dinos. I strongly suggest doing some research on the treatment and identification of Dinos, including the importance of keeping elevated nutrients during an outbreak. Another great resource is the Dino mega thread on R2R, named "Dinoflagellates – Are You Tired Of Battling Altogether?". 




Hope this helps. 






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