fishmoniker

Hello there, I've searched this forum before but only registered today. About a month ago I decided to get back into aquarium fish. I bought a 20 gal. with all the supplies needed to start. My girlfriend insisted on getting guppies and so after everything was set up she picked out 6 male guppies for the cycling period. We've had them for about 2 weeks now and everything is going perfectly, steady temperature, fish all active, and very, very low ammonia. And that's my problem. I haven't seen a rise in ammonia, at ALL, in the two weeks that we've had the fish. Not the slightest trace of nitrite. I feed them once every other day.

My question, finally, is this normal? I have no clue how long cycling takes. Does it vary from tank to tank? Or is there an average? Will patience win this battle?

Another question I have is about evaporation. I never seemed to have this problem with my last tank, but I get a lot of evaporation over the days (about 1 inch gone every three days). To combat this I've been doing about 25% water changes every Wednesday and Saturday (just got done doing it). I was wondering if this is hindering the cycling period? Should I continue this pattern? Is there anything else I can do to slow evaporation (like a different brand of light)?

(To complete the tank once it's done cycling I want to get four corys.)

Any reply or insight will be greaty appreciated, and I thank you in advance.

edit: I searched for this but couldn't really find anything that answered my question, I apologize if this was discussed before.