API test kits are good. One comment on the nitrate one, it says to shake Bottle #2 for 30 seconds--this is not long enough. Shake it for 2-3 minutes and the results will be accurate. I learned this from another forum; when the regeant is shaken only for 30 seconds people were getting false (quite high) nitrate readings.
Stores are famous for telling you the test is OK or pretty good or not good--without saying the exact numbers. Now you can do your own, much better.
The test numbers indicate your tank is (probably) coming out of the second stage. Ammonia has spiked and is now zero (provided it remains zero, that's good), nitrite is now high, but that is normal in the cycle and this should drop off to zero (over the next couple of days) and stay at zero. Daily pwc of 30% will help ease the stress of this nitrite on the fish. Once both ammonia and nitrite are at "0" and remain there for consecutive days, the tank is "cycled" for the bioload it contains.
Nitrate at 5 is very good; it will also rise once the nitrite has peaked and fallen, the third stage of the cycle, and nitrate of less than 20ppm is considered good. Most fish can tolerate nitrate to 40ppm, some much higher, but it is safest to aim for under 20ppm. The weekly pwc of 30-40% is the best way to achieve this. In a planted tank, the plants keep the nitrate below 10ppm unless something drastic is done to upset the biological equilibrium.
Re the ich--and yes, if you are like most of us, you will probably see this parasitic problem again--I am not a fan of salt. I'm going to be posting a length comment on salt in another thread momentarily, as I was asked for advice and I believe salt is the culprit there; so I won't go into all that again here. You may find it helpful to read what I post later:
http://www.fishforum.com/tropical-fish-diseases/synodontis-eruptus-flaky-peeling-cloudy-skin-30326/
My preferred treatment is to let it work itself out without intervention. This, if it is light (say, one or two spots on one fish only). It usually does, provided the fish are healthy, the water quality is good and stable. Ich is almost always present in our aquaria; some will dispute this, but there is evidence. I have had it appear out of nowhere, and there is no other explanation when nothing has been added to a tank for months, and ich suddenly appears. The fish are capable of fighting it off, along with many other things, if they are healthy and the water quality is maintained by weekly pwc, not overfeeding, and plants help a lot.
When it gets persistent, as seeing 3 or more spots on several fish, I use Aquari-Sol for 5-6 days. I do not raise the temperature because I keep my tanks at 78F and some of the fish I have do not do well above 80F and the heat stresses them out even more than they might already be due to fighting the ich. No point in adding to their misery. I have always cured it in 4-5 days; I maintain the daily dose for 5 or 6 days, depending upon the severity and what results I observe. This medication does contain copper--most ich remedies do, and it is the copper than some fish cannot tolerate well. But it seems to be less in Aquari-Sol which is stated to be OK for sensitive fish (most tetras and catfish) and in my SA tanks of all characins and corydoras with Farlowella (very sensitive to any chemical) I have not had a problem, but I have with other copper medications that drive the corydoras and Farlowella round the bend, literally. So I recommend Aquari-Sol for any parasitic infestation when it is severe.
Byron.