Help please! new planted tank emergency
I have a new (to me) 29 gallon tank that is experiencing a bit of a crisis.
It has been up and running for 2 weeks. I started it out pretty heavily planted and read that a planted tank can do a 'silent' cycle, so no real need to wait for it to cycle before adding fish.
A few days after I set it up, I checked the levels with a multistrip and things looked fine so I added a pair of halequin rasboras and 6 ghost shrimp. The rasboras have done great and have even been laying eggs and producing a few fry. The ghost shrimp have been slowly dying off - which is fine with me since I wanted to add cherry shrimp and heard they don't get along so well..
Two weeks later... I assumed that the silent cycle was a success and my tank was ready for more fish. So I bought a bunch more fish.
10 white cloud mt minnows
2 more rasboras
4 black neons
3 cory cats
30 juvenile-adult cherry shrimp
BUT, before I added them, I thought I should check the parameters again - and it turns out my Nitrites were sky high. (>10ppm according to the test strips). I bought a real drop-style test kit (>5 ppm, which is as high as the chart goes). Did a ~60% water change and added some tetra safe start... no change - still >5ppm, even after 12 hours.
I have all the new fish in a separate bucket, with their fish store water, heater and air.. I am afraid to move them into the aquarium until the nitrites come down, but they can't stay where they are either.
Ammonia is zero.
I assume that my tank has just not completed it's cycle and I need to keep doing water changes and wait it out. Other potential explanations are that my filter is too small. It is too small - I got the setup off craigslist from a guy who seemed to know his stuff but he gave me a 5-15 gallon filter for a 30 gallon tank. Is this my problem? Another potential issue is that I was feeding a lot, probably too much - trying to get some food to the fry, and I was away the past 3 days and had one of those 'vacation' feeder blocks in there, which was a nasty mess when I came back..
What should I do?
At what point would it be better to try to acclimate the new fish to the high nitrite water, rather than leave them in an unfiltered, over crowded bucket?
The test kit recommends using nitrizorb to lower nitrites - is this a good idea?
I've read that 1 tsp salt/10 gallons can help fish in high nitrite conditions.
I'm not opposed to buying a separate 10 gallon, and moving the new fish in there until the big tank stabilizes, but that tank won't be cycled either..
Do I need a bigger filter?
I used 1/4" of miracle grow under the gravel
the two adult rasboras and two fry (which I had sequestered in a breeder box, in the main aquarium) are alive and seemingly fine. One ghost shrimp is still alive.
The plants were growing very well for the first two weeks, but some of them look a little melty now. It is a old single tube T-12 fixture and I switched from a pinkish "aquarium and plant" bulb to a whiter "6500k" bulb about a week ago - could that be related?
Should I add some liquid ferts for the plants ( I hadn't done that at all yet)?
Thanks for any help you can offer!