If they were my tanks, I would start doing major water changes (~50% per day) to make sure ammonia and nitrite were both well below 5
ppm. Also, with high nitrite I have read fish have problems breathing, so people often suggest lowering the temp a little bit (the lower the temp, the more oxygen can dissolve in the water) and adding extra aeration, by putting in another bubble stone and/or lowering the level an inch or two (if you have a
HOB filter) so that the filter water makes more splash when it hits the surface.
What is in your 45? If the 45 has no ammonia and no nitrite, then that tank is cycled. At which point, you can probably help get your 55 and 70 tanks further along by getting some of the "gook" from the filter on the 45 and putting it into the filters of your other two tanks. Also, you could take a handful of gravel fro the 45 (which should also have some of the bacteria), put it in a filter bag or even some pantyhose, and plop it in your other tanks as well.
But your #1 priority has to be water changes to get the nitrite down to below 1
ppm. Which means the next few dyas are gonna be busy days for you.