Brand new with two tanks

Hi Everyone,
I found this site because I was looking for a good freshwater fish shop in the Portland, ME area and posted on Craigslist. One of the members of this list sent me the link and here I am.
I have two 10 gal freshwater tanks. Both were second hand so I got them cheaply. I major league messed up the first tank by overfeeding three weeks ago. I purchased my starter fish (three platies - M Red Wag, F Sunset, and F Mickey Mouse). The Mickey Mouse had babies the very next day! I saved 12 of the babies before they were gobbled up and that's when the overfeeding started. The tank at that point was only about 5 days old.
Since then I've been through all kinds of hell trying to save the F Sunset (she's doing remarkably well now), but lost the Mickey Mouse. I replaced her with a M Mickey Mouse. I'm still fighting through some higher levels of nitrites but those are coming down and I've started cycling all over again.
The second tank currently is cycling with Neon Tetras. Yes, I know, they are bad for cycling a new tank. Didn't find it out until it was too late (Petco also didn't let me know even after I told them I was looking at starter fish, I thought all Tetras were fine). I'm down to two and one is looking bad (started showing some signs of Ich this morning).
This is all why I was looking for a good freshwater store. I did stumble on a great marine shop in South Portland if anyone on this list might be interested. The woman who owns it has been a great help in getting my tank straightened out.
Thanks for listening. My mother thinks I'm nuts. I got the tank for my cat, but now I'm hooked! Trying hard to do the best I can.
Karen.

 

Hi Anthony,
The Ich I've got a grip on. It's been this water chemistry stuff that's been kicking my butt. I would welcome suggestions about an inexpensive but accurate water test kit. I'm using strips right now, but the marine shop I've been getting my water tested at says those are unreliable. Thanks!

 

glad to have you!

 

Thanks for all the welcomes and helps! Looking forward to utilitizing all the help in the regular topic areas. Thanks again.
Karen.