Green algae in sand

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MarkW19

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Joined
Mar 25, 2004
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I had a bad algae outbreak a few months ago, but it's now settled down and all the brown and hair algae is gone.

But, over the past 10 days, a lot of green algae has been appearing in the sand, and looking at the underneath of the sand from the side of the tank, it's going through to the bottom of the substrate too - bright green in places! But more of a dull green on top.

I'm running rowaphos, which along with my hermits helped get rid of the algae before. But now it's come back for some strange reason...

All other parameters are ok, and I use RO water (2 TDS) and phosphates are undetectable. I would guess it'd be about time to replace my rowaphos, but seeing as my phosphates are ok, I guess not?

Anyone any ideas? All other parameters are fine. Light is 12 hours a day from 2pm to 2am.
 
Phosphates may test 0 if they are being used up as they are created. How's your water flow? Nitrates?
 
Waterflow could be better but is fairly good - powerheads turn over about 7 times water volume an hour, plus my filter which creates a lot of water movement as it's constantly blowing water about. Nitrates unmeasurable.
 
If you are using an external filter make sure you are cleaning it often. Chemical media when exhausted can start leaching whatever it absorbed back into the water. Also make sure your bulbs aren't past their useful life.
 
How exactly do I clean my external filter?? It's an eheim external canister, wet/dry.
 
Rinse the sponges, media and whatever else that can trap debris. This will need to be done at least once a week. If you are using these filters as your bio filter make sure you use tank water to clean. Most reefers no longer use these filters as they need constant maintenance.
 
Mike - will do. Can phospahtes be different at different levels? My test was just taken from the surface.
 
Mark Phosphates enter the tank from many things and in many ways. Here is the quick and dirty on finding P sources.
If you get a reading of P on a standard test kit, it is telling you that your tank is saturated with Organic P (kits only test for Inorganic P), so in other words thier is so much Inorganic P in the water that the critters in the tank cannot bind it all.
When you do a test in the water column you are basically looking to see what is soluable and inorganic and in the water stream. This is good but alot of times the available Inorganic P is taken up by bacteria or algae prior to making it to the open water. The fact you have algae present tells you that thier is some present. LR naturally sheds detritus (P, N) so taking a reading from right on top of the rocks will let you know if it is collecting thier. If the test is zero the you now you ont have a problem with collection, if its positive then its time to blow the rocks and keep the detritus from building (should do that no matter what). If you take a test of the water just inside the surface of the sand bed (dont worry about a few grains being in the test) it will answer if or not the bed is leaching P. From thier thier are things that can be done.


Mike
 
Cool - I guess algae in the sand won't do any harm though, apart from aesthetics?
 
Well according to Dr. Ron (the dsb guru) that is exactly what a dsb is supposed to do. Facilitate the removal of nutrient through algae harvesting.


Mike
 
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