The best way to lower ammonia levels is to perform large water changes
(50%-75%) in a ten gallon tank that should not be too hard. Your ph
may have dropped because your water quality is degrading. How long has
it been since your last water change? How much water do you normally
change? I do 50% weekly water changes on my tanks and I am not having
water quality issues. Goldfish are quite messy fish and need extra
filtration and larger water changes than tropical fish. On another
note, you may find that as your fish grow your tank will become
overstocked. Not sure what type of algea eaters you have but they dont
normally mix well with goldies.

Hope this helps, Maria

What type of food are you feeding now? Both types of fish you have
will really enjoy some fresh succhinni (sp?), oranges or green leaf
lettuce. Rinse, slice and stick to the side of the tank with a veggie
clip (can be purchased at your local fish store)