[elTwitcho]

First you need better filtration on your 75 gallon.

Second, add a tablespoon of table salt to the tank to deal with the nitrite levels. It sounds like your tank is in the middle of a cycle and the salt will prevent nitrite poisoning.

 

[elTwitcho]

Actually the whispers might work ok on second thought, they're not really great filters but if you watch your levels closely you'll know if you have a filtration problem. If the whispers aren't enough I'd recommend an AC500 with some ceramic rings in it for bio filtration, but then whispers might be adequate anyway. The ACs are cheap and are the best designed hang over back filters on the market so that's something you should keep in mind if you need to get any extra filtration on there.

 

[elTwitcho]

Yes, sorry I should have been more specific

 

[elTwitcho]

Most fish stores should have them, bigalsonline.com is an option for mail ordering if you can't find them, but I doubt you'll have trouble

 

[elTwitcho]

With the salt your fish won't be killed