bubbles (suds) at the top of my tank

Question
When I got the tank I just wiped it clean with a wet rag and I just rinsed everything off (plants,gravel,etc).  What's weird is that as soon as I open the tank lid,the bubbles will slowly start to pop.  Do you know what that might mean?? In answer to the your other question, I use "Start Right" as a dechlorinater. But this has something new added to it called "Allantoin" a natural skin protectant. Could that cause the bubbles.  I am sort of familar with tank cycling,(I also have a 20 gallon tetra tank)but how long does it usually take? I dont remember having problems with the tetra tank,but that tank is about 5 years old.  Thanks for your help :) :)
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The text above is a follow-up to ...

-----Question-----
Hi there!  I just recently set up a 20 gallon tank and got a few angelfish.  I noticed a thin layer of bubbles (suds) that formed on the top of the tank a few days after I set the aquarium up. Someone told me it could mean high amonia levels. Is that true??
-----Answer-----
Hi Heather
I've never heard of ammonia causing that to happen, though that doesn't mean it's not the cause.  I learn something new with fish stuff everyday.  My initial thought though, is what kind of dechlorinator are you using?  I can't think of the name off hand, but there's one that has aloe in it, that would cause some bubbles.  A lot of other additives/chemicals that we use in tanks can cause bubbles as well.  When I use MelaFix for treatments, that will cause some bubbles on the surface as well.  Are the bubbles still there or was it just a one time occurence?

My next thought, since it's a new tank, did you clean the tank first, and if so what did you use to clean it?  Obviously soaps or detergents would cause this as well.  It could be a left over residue in the tank if you used some soap/detergent to clean.  Even if you used regular ammonia to clean the tank, there's additives in there as well.  And, anything else in the tank, gravel/substrate, decorations included.  Did you rinse the gravel out first?  Is this a glass or plastic tank?  I've heard before that the plastic ones can retain some chemical residues on them as well.  If you did clean anything in the tank with something, I'd recommend breaking it down and thoroughly cleaning everything including the tank.  That's one thing that'll kill a fish real quick.

Next question, is the filter agitating the water good?  If not, try dropping the water level a little bit and see if that helps.

I know you didn't ask for this advice :)  But, are you familiar with cycling a fish tank?  I ask, because angel fish probably aren't the best fish to cycle a tank with.  That size tank is also kind of small for them, I wouldn't add any more fish to that tank.  Here's a link for you, have to copy/paste it to your broswer.  Gives some basic care info for them.

http://www.liveaquaria.com/product/prod_Display.cfm?pCatId=1175

Good luck and let me know if you have any more questions!!

Christy

Answer
Hi Heather
Try dropping the water level a bit, to increase water agitation/gas exchange and see if that helps.  I looked up that Allantoin real quick, there's an article on Wikipedia about it.  Seems like it's kind of like aloe.  I'm not sure if too much of that stuff will cause the bubbles, I'm not familiar with it.  

I'll post a link at the bottom for fish cycling.  Read the articles on there, and get familiar with it.  It's important stuff to know, because a lot of times when people start having problems with their fish, it's due to water quality.  Any traces of ammonia or nitrites can stress/kill the fish or cause diseases.  But if you're familiar/understand the cycle process, it's easier to diagnose a lot of problems and treat them quickly.  If you don't have one for your other tank, I'd recommend buying a testing kit.  The dropper test kits are more accurate then the dip strip kits.  You'll want one that tests for ammonia, nitrites, and nitrates.  Those readings once a tank is cycled should always be ammonia and nitrite 0 ppm, and nitrates under 20 ppm.  The best way to keep those levels, is to not overstock your tank, and do weekly water changes, usually about 25% of the water.  Doing weekly water changes is the best thing you can do to prevent lots of problems.  

Now, what you can do, scoop out at least a handful of gravel from your tetra tank, and drop it into the new tank.  There's beneficial bacteria on the gravel, and that'll help kickstart the cycle in the new tank.  A normal tank cycle takes about 4-8 weeks to complete.  Addin the established gravel though, will cut it down considerably.  I keep a little mesh bag of small bacteria bio-balls floating in one of my filters, and if I ever need to start a new tank or have to use antibiotics-which can kill off the bacteria in an established tank, I just pop the bag into that tank.  It's like instant bacteria lol.  

http://freshaquarium.about.com/od/startupcycle/Step_5_The_Cycle.htm

Hope that helps!!  

Christy