A goldifish of any kind needs at least 10 gallons of water per fish and 10x the filtration. Now, the filtration level will drop with tubing and such so a 10x rule is just one to go by. Meaning, if you have a 5 gallon tank you need x 10 gallons per hour of filtration . Filters will tell you what their GPH is.
Are these Eclipse tanks? Your bio wheel will trap and oxygenize good bacteria. NEVER WASH IT, and USE IT!
I do not suggest goldies, your tanks are WAY too small. Make sure before you get any fish, you do a lot of research about what is compatible and what size tank they need.
A test tube based test kit testing ammonia, nitrites, nitrates and PH is NOT an option, and neither is a good water conditioner, like PRIME.
Please, take some time, the net if full of good info....if you prepare your tanks properly, you will have a lot less problems.