Film on the water surface

[robinos]

My tank is cycling. I did my first water change yesterday afternoon. When I got home today, I flipped. There was my snail, flipped on his back, motionless. The fellas, my 3 ghost shrimp were not moving, hiding behind the driftwood. On the surface was an irridescent film. What's that? I was panicking, I drained some of the water. What's going on?

Now that I've typed this I've calmed down a bit.
My own hypothesis:

When I did the water change, I added more water than I removed. This reduced surface aggitation from the HOB filter. The film (still don't know what it is) was able to accumulate. The livestock were deprived of oxygen.

When I brought the water level down, surface aggitation increased providing more O2. Immediately, (yes, immediately) the snail picked up and started cruising around like nothing ever happened. Shrimp started looking for food and eating. And I was able to breathe.

Water Parameters yesterday, after water change:
Ammonia:1.5ppm
Nitrite:4.0ppm
Nitrate:6.0ppm
pH:6.8 kH:30ppm gH:125ppm

Water parameters today, after traumatic experience:
Ammonia:0.5ppm
Nitrite:2.0ppm
Nitrate:8.0ppm
pH:6.8 kH:40ppm gH:150ppm

Any insight?
Sorry about the lengthiness of the post, I panicked. This is my first tank.
I appreciate any help.

Thanks,
Robin

p.s.- for anyone out there: Keep a log! It really helps to keep track of all of your previous levels and note observations.
o.k....I'm done now.

[Slappy*McFish]

It sounds like you rectified the problem by increasing the surface aggitation...which is exactly what you needed to do. The biofilm is normal and occurs in all tanks with little or no surface movement. Aeration is the key. Your cycling tank needs all the oxygen it can get right now and it wouldn't hurt to increase the aeration a bit more, if possible.

[robinos]

Thanks, Slappy.
It's bubbling nicely now.
-Robin

[tricksterpup]

Hey Check out this link here.
http://www.aquariacentral.com/articles/scum.shtml

[Roan Art]

robinos --

It might give you peace of mind to add a bubble wand until your tank is cycled. This will ensure that the surface is constantly agitated and gas exchange takes place.

Roan

[Marinemom]

Keep the bubble wand even after the cycle. It breaks more oxygen at the surface and besides, it's pretty.

Marinemom

[Roan Art]

Keep the bubble wand even after the cycle. It breaks more oxygen at the surface and besides, it's pretty.

Marinemom
Bubble wands and airstones are unnecessary in a properly filtered tank. They are also detrimental in a planted tank as they will gas off the CO2 needed by the plants.

Roan