Air stone or stagnant water

[JoshBA]

I have a semi aquatic tank with lots of wood and a quartz sand substrate. I originally kept an air pump running with 2 air stones in the (4ft) tank, but I eventually took them out due to the pump's irritating noise. But with no surface agitation, the water becomes pretty stagnant, and I can smell the boggy smell of methane gas on the driftwood pieces. Also, a biofilm develops on the waters surface, which presumably restricts some oxygen (and I'm afraid will create anaerobic conditions). Will the tank be fine as long as its stuffed with plants, or should I still keep the air pump? I'm sure there is some methane producing bacteria in newts' natural habitats, but will it cause harm in captive conditions?

 

[Chinadog]

I always run an airstone in my tanks but only bubbling gently, the bubbles bursting at the surface help to brake up any scum there might be without creating much water movement. Also the filter bacteria need oxygen to do their job, the more dissolved oxygen in the water the more the bacteria will flourish and the more efficient the filter will be! Not sure about the smell you mention, i think if there's a smell there's something not quite right somewhere? Maybe the tank isn't fully cycled yet?

 

[JoshBA]

Thanks for the reply. I'll just keep the air stones in then. I believe the bog smell was being created by bacteria from a low oxygen environment.

 

[otolith]

I always use sponge filters which provide a bit of water circulation but don't really create any turbulence or current. They are great for heavily planted set ups and larvae tanks since nothing really gets sucked into them. Have not had any water chemistry issues.

If you have a deep layer of sand that may be the source of your methane build up; lots of detritus and no air to break it down.

 

[JoshBA]

Although the sand is only around 0.5in deep, there is some soil in it that I spilled when setting up the land area (so I suppose that may be a large part of the problem). I'll keep the air stones on and probably eventually get a sponge filter. I may end up taking the sand out and rinsing it to get the soil out (even though it will kill any beneficial bacteria), or I'll replace it will a sand of smaller grain size.
The pool filter sand that I have in there seems to have multiple grain sizes, with some at 1mm. It also is very light, and is stirred up really easily. This makes me a little paranoid that my newts' guts may become impacted when they are feeding (once I put them into the tank). What would you suggest for me to do with the sand? Replace it or keep it?

 

[Chinadog]

I use childrens play sand in my set ups, it sounds similar to what your using. I wouldn't worry about the newts ingesting it, my adults can easily catch live or dead food off the bottom without getting any in their mouths. they sometimes eat small snails with sand stuck to them but they somehow spit most if not all of it out. I think its gravel that they can't pass through their guts that causes the problems.

 

[JoshBA]

Yeah now i'm noticing more multi-grain sizes in the sand, which is strange for pool filter sand. From stirring the sand, more and more larger pieces are settling on top. So, I think i'm just going to replace it in order to avoid impaction. I would get playsand, but the 50lb bag seems a bit much for just this one tank.
I'll probably end up buying some black sand from the pet store. Its perfect grain size, I think it looks awesome, and I really don't care about cost because I won't need very much.