Goldfish ponds/aquaria

I'm new to this group so apologies if this has already been covered.

I have an outdoor pond stocked with goldfish. My original 10 goldfish are
very prolific and I now have more than 100 fish of various sizes and types.
This year alone the outdoor pond has generated over 30 new fish.

I'm in zone 6 and we've had a few brutal winters in the past two years. To
preserve my finned friends, I built a 300 gallon indoor pond and also have a
100 gallon aquarium and a 29 gallon aquarium--all overstocked!

Here's my problem and I'd appreciate help. I appear to have a pretty severe
ammonia problem in all the indoor tanks. Although I haven't lost a single
fish (and they are breeding in the 300 gallon tank) I keep getting ammonia
readings off the scale on the standard kits.

I do water changes, charge the aquaria with Cycle or MicrobeLift but the
readings are still high. I put ammo rocks (or chips as appropriate) in the
tanks but still get high readings. Nitrates are also usually pretty high.

I hate to get rid of my fish but I need to fix this problem. The fish range
in size from tiny fry (1 inch or less) to 6-8 inches long.

Any ideas would be appreciated.

I hate to make this a marathon post and would be glad to discuss additional
details offline.

Thanks to anyone with ideas.

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