Sounds like your bio filter is not large enough or is not working.
Perhaps you have cleaned it recently and destroyed the bacteria. If so
..........
I would treat with Amquel and reseed the filter with some kind of
bio booster. The fastest way is someone else's filter media to jump
start yours.
Also .... Has your water utility recently switched to chloramines?
Disregard if you are in the part of Howell with private wells.

--
My little puddle

http://www.geocities.com/hankpagel/hankspond1.html

"Tom Puskar" wrote in message
et...
I'm new to this group so apologies in advance if this has been
discussed.

I have a 300 gallon indoor pond (started off as a winter haven for
my
outdoor pond fish) and I'm having a lot of trouble with ammonia
levels. The
pond is probably overstocked with goldfish but they all look
healthy. I get
ammonia numbers off the chart using a standard test kit.

I can provide construction details including filter type but it
would make a
long post. I'll be glad to do it offline.

Anyone else have an indoor pond? Is there a newsgroup somewhere
that
focuses on indoor ponds?

Thanks to anyone who replies.

--
Tom Puskar
34 Old Bridge Drive
Howell, NJ 07731
Phone: 732-905-5728
Fax: 732-905-5847