play sand in the tank...

[Mouth-Brooder-Fanatic]

im havingmega problems with one tank. its a grow out for juvies so has an incredible bioload and needs extra care and filtration. however.
the sand was play sand from a garden centre, and has recently turned blue in the lower layers.
a week ago i done a pwc and shook up ALL the sand and removed 90% of this water and all the gross stuff. the blue parts of the sand smelt disgusting, like sewer tbh.
i done another pwc today, same thing (and smell!) but now all of the sand has a blue tint and im thinking of just going back to gravel, even though i have loved the sand effect.
whats going on? is the sand going MOULDY? eww. x

 

[Jnthn932]

Shoulda gone with PFS. I've never heard anything good about play sand. I would just take it all out and replace with PFS.

 

[Mouth-Brooder-Fanatic]

where can i get that from? x

 

[jcolon]

Depending on how deep your playsand is, what maybe happening is the fine sand is restricting oxygen from getting to the deeper layers, leading to an anoxic zone.
The sewer like smell could be the gases the anaerobic bacteria in those anoxic layers create. It's been known to happen

Consider switching to Pool Filter Sand ... it gives you the best of both worlds IMO. It's fine enough to give you the sand effect, but coarse enough to allow more oxygen to flow into the deeper layers. Plus PFS will not cloud up like some playsand. Since it's more coarse, it sinks right away instead of floating in the water.

 

[Jnthn932]

It doesn't cloud up if you properly clean it. When I first bought PFSi didn't clean it right and my tank was cloudy for days. It also ruined my filter. You can get it pretty much any pool supply store. I get from Home Depot. It's like 5 bucks for a 50 pound bag. Make sure you clean it right and turn off your filter when you put it in your tank.

 

[Mouth-Brooder-Fanatic]

thank you! thats so much clearer - i just need to find the pfs and tada. so what is no oxygen getting to the sand? why does is even need oxygen? x

 

[Mouth-Brooder-Fanatic]

and i did clean my sand, i cleaned it til the water ran crystal clear from the pillow case. went in the tank and settled within 2 hours then no cloud. recently though....

 

[jcolon]

thank you! thats so much clearer - i just need to find the pfs and tada. so what is no oxygen getting to the sand? why does is even need oxygen? x

The reason you'd want Oxygen is to avoid the anoxic zones since anerobic bacteria cannot survive in an Oxygen environment. Those bacteria can produce some noxious gases, give can give a sewer / rotten egg odor. In an aquarium it usually doesn't present any danger to fish. See the link below for information on nitrification and de-nitrification.

Aquarium Nitrogen Cycle and cycling. Methods for ammonia, nitrite removal.