Hello. I tested my 10 gal. tank that I have had for about 6 months with 1 axl. I use a sponge filter. Here , are my results: ph- 7.6, Amonia- .25, nitrite-0, nitrate- 20. I figures the amonia should be lower, but not sure how to get it down. Do some partial water changes? If so, how many and how often? Is there a listing of normal values for axls somewhere? Thank you for your help. Denise