Black layer of sand

[cajamajo]

I have a problem with the bottom layer of sand being balck. If you look up through the bottom of the tank you can see black. The sand is about 2" deep. I have:
35 gal hex
prizm skimmer
2 maxijet 1200
fluval 404
40lbs live rock
ammonia 0
ph 8.2
nitrate 20
nitrite 0
sg 1.024
I can turn over the sand and the black will go away. It is even under the live rock. The whole bottom it black. I have some green tint algae on the glass and on the rock where the coraline is not. Brown algae covers the bottom in a matter of hours "if the flow is not on the sand". On the back of the live rock the rock has a red tint to it "shaded part of the rock" it does not look like actual algae. I was thinking it was cayno. It has a bad smell if the sand is stirred. It started about 2 or 3 weeks ago. I was adding This is what I have done so far:
added phos-zorb to fluval
added act. carbon
adjusted flow to keep sand clear
cut light back to 5 hours day"was 10"
cut feeding back to every 3rd day
changeing 10 gal a week.
stoped adding chromaplex
Can anybody help me with this. I feel like I am loosing the war.

 

[sepulatian]

Originally Posted by cajamajo
I have a problem with the bottom layer of sand being balck. If you look up through the bottom of the tank you can see black. The sand is about 2" deep. I have:
35 gal hex
prizm skimmer
2 maxijet 1200
fluval 404
40lbs live rock
ammonia 0
ph 8.2
nitrate 20
nitrite 0
sg 1.024
I can turn over the sand and the black will go away. It is even under the live rock. The whole bottom it black. I have some green tint algae on the glass and on the rock where the coraline is not. Brown algae covers the bottom in a matter of hours "if the flow is not on the sand". On the back of the live rock the rock has a red tint to it "shaded part of the rock" it does not look like actual algae. I was thinking it was cayno. It has a bad smell if the sand is stirred. It started about 2 or 3 weeks ago. I was adding This is what I have done so far:
added phos-zorb to fluval
added act. carbon
adjusted flow to keep sand clear
cut light back to 5 hours day"was 10"
cut feeding back to every 3rd day
changeing 10 gal a week.
stoped adding chromaplex
Can anybody help me with this. I feel like I am loosing the war.
When you do water changes are you vacuming the sand? A 2" sand bed is too shallow to rely on it for biological filtration. The black that you are seeing is just detris that settles. Do you have a cleanup crew?

 

[beth]

I would never vacuum, since this will destroy the biological filter. However, a cleaning crew of snails, worms, should get the job done. Is that live sand? What is the particle size? Its not crushed coral, is it?
What do you have in that fluval?

 

[sepulatian]

Originally Posted by Beth
I would never vacuum, since this will destroy the biological filter. However, a cleaning crew of snails, worms, should get the job done. Is that live sand? What is the particle size? Its not crushed coral, is it?
What do you have in that fluval?
Your absolutely right beth, I did not ask what kind of sand. I was thinking plain sand which I always vacume, my appologies.

 

[cajamajo]

I have
12 blueleg hermits
6 nassarius snails
10 bumble bee snails
knobby star
watchman goby
I do not vacuum the sand. I dont know much about the sand it was not alive it was just fine white sand the pet store had. The sand might have been named white castle? I seeded it with a cup of live sand a friend gave me from his. All I have in the fluval is phos-zorb and act. carbon. I clean the 4 filter media monthy

 

[cajamajo]

I just turned over a hand full of sand. It was not black like it was last week. The top of the sand was hard compacted. The sand on the bottom was grey, and fine. I turned it over it was white in about a minute. I dont understand how it turned white so fast the filters were not on the water was not moveing.

 

[beth]

Add more nassarius and get spaghetti worms. There are sites online that sell them.

 

[beth]

Originally Posted by sepulatian
Your absolutely right beth, I did not ask what kind of sand. I was thinking plain sand which I always vacuum, my apologies.
Sep, humans mixing up any kind of substrate is always a bad way to "clean". The primary filter is the biological filter that is made within the tank environment, and the largest producer is in substrate. Disrupting substrate, therefore, disrupts the biofilter. Better to rely on natural filters to do the job. They are better at it than we will ever be.

 

[cajamajo]

Beth,
I was editing my last post when you posted. I dont think you were able to read it. Will the worms keep the top of the sand from getting hard?

 

[beth]

Did you read what I said?? Don't fool around with the sand. Let the detritivores do the job. You should encourage as much sand critter activity as you can. Worms, including bristleworms, should be encouraged.

 

[sepulatian]

Originally Posted by Beth
Sep, humans mixing up any kind of substrate is always a bad way to "clean". The primary filter is the biological filter that is made within the tank environment, and the largest producer is in substrate. Disrupting substrate, therefore, disrupts the biofilter. Better to rely on natural filters to do the job. They are better at it than we will ever be.
Gotcha Beth

I was always under the impression that if the sand bed was shallow that stirring/vacuming it was the best way of keeping it clean and free of buildup. I rely on my rocks and filters for biological filtration. I certainly see what you are saying though. Natural filters are best for the enclosed ecosystem.