Film on surface of water?

[Jzehr125]

Hello all. I've set up a tank for a juvenile axolotl, which I will be getting soon. Last week, I noticed the water temperature was a bit higher than it should be (about 66-68F and 20-22C), so I took a clip-on fan that I have and clipped it onto a nearby surface to have it blow air across the surface of the water. The temperature came down to 64F (18C) and I was pleased. Then I left on Friday and returned on Sunday to find a thick film across the surface of the water. It was almost like a skin - once broken, it stayed together in chunks. The water level had gone down about half an inch, and when I added more water, the chunks floated around in the water, seeming not to sink or float. The filter I have is not overly powerful, and was not picking up much, if any, of these. So I used a siphon to remove most of the water, and cleaned out everything in the tank. I rinsed out the tank, cleaned the sand, rinsed all the decorations and plants, and when it seemed clean and then some, I set up the tank again, adding completely new water. When I put the plants back in the water, I thought I could see a bit of the film on their roots, but I was unsure. This was last week. This week, I kept the fan off for a bit, and turned it on last night to begin cooling the tank again. I had it on low most of the day, found that it was not doing as good of a job, and turned it on high again. This morning, I found a thin film on the surface of the water again. It was not as bad as before (not as thick), but still a film. Both times I smelled the water to see if I could smell anything off, and I didn't notice anything, other than what could be either a normal "green plant" smell, or what might just be a normal water smell. After I had finished with the siphon, bits of the film stuck to it, and when they dried, they looked like white scale. I'm really not sure what to make of this, as the fan seems to be the trigger. I've used water for my betta's tank as well from this same area, and never had a film develop. I've used a dechlorinater for the water before putting it in the tank. I unfortunately do not have water parameters to offer at the moment, as the local pet store only had a pH testing kit in stock. I'll check back later and see if they have a drop test in stock. I have sand in the bottom of the tank (I washed it before putting it in the tank), two different varieties of water sprite, two hides (made from resin, I believe), a filter, a ping pong ball, and a thermometer in it. I'm really not sure what to make of this. The only thing I can think is that the fan might be evaporating the water and leaving behind some portion of "stuff" (minerals?) behind. That, or maybe one of my decorations was meant for terrarium use rather than aquarium use, and I grabbed it by mistake. Could it be a large quantity of dust/dirt blown onto the surface from the fan? Some of the water sprite leaves are floating with roots, but the plant doesn't seem to be in that great of shape. Could it be due to potentially rotting plant material? At first I thought it might have been a one-time water problem, but with this second event, I'm rather concerned.

Do you have any idea what this is or what I can do? I'd provide a photo, but the film doesn't show up well in its current state.

Thank you for your time.

 

[kirstyandmark]

I sometimes get this film on the top of my tank water too and i dont use a fan at all i dont relly know what causes it but i usually just get it out personally iv alway put it down to the way the water settles and bits of dust ect i dont think its anything to worry about but it would be good to find what causes it

 

[siona]

I also sometimes get a thin oily film...It is annoying but doesn't seem to be doing any harm. Not sure about the thick stuff you described though :s

 

[Jzehr125]

I think I noticed what you're describing on my betta's tank from time to time. Not really colored, just a light bit of a sheen?

What I've noticed on the future axolotl tank, at its worst, wasn't colored, but had a whitish tint. Not a lot, probably more just because there was a lot of it gathered there, I assume. It was about as thick as the skin on a tomato soup when you let it sit for a few minutes. This time, it's not nearly that thick, but...yeah. Glad to hear that some bit of filming is normal.

 

[Kaysie]

It's dust.

Water has a REALLY high surface tension, and when you use a fan to blow air across the surface, you also blow little bits of dust, which stick to the water (thanks to the surface tension), and create a film.

You don't normally notice the dust because most people have a filter or a bubbler running, which agitates the surface (and breaks that tension).

Also, did you know the majority of dust is made from human skin cells? Since the air has much lower humidity in the winter, we tend to slough more skin cells than normal, and if you have forced-air furnace, there is a lot more dust blowing around.

 

[Jzehr125]

That's a relief, thank you! I actually do have a filter going, but it's not overly powerful, and I didn't have it on the highest setting, so that could be part of the problem.

 

[siona]

wow the things you learn! How do you know this stuff!? Thanks for enlightening us!

 

[Kaysie]

Just stuff you pick up along the way, Siona. You'll know lots of things too!

Jzehr, you may want to try adding an airstone to the opposite side of the tank. That'll help with circulation, as well as surface agitation.

 

[ax]

oh I heard it was a protein build up, but your explanation makes more sense

 

[Kaysie]

Protein usually manifests itself as an oily film or sheen, rather than a white, chunky film. The key is when she said it sticks together in chunks. Protein film doesn't usually do that.

If you have really hard water, it can cause chunks too. This can be especially true if you have a high evaporation rate. I've noticed since I moved here, the water's much harder and causes more of a crust on the edges of the tank.

 

[ax]

Oh yeah, didn't read properly...