You should have a source of ammonia to get a good cycle. You don't want a situation where you have grown some nitrifying bacteria but not enough to handle the waste fish produce, then when the fish get added you get immediate ammonia spike and have to re-cycle your tank. Your ammonia could be as simple as some fish food you let rot or it could be a pure ammonia product.Hi all, new to planted aquariums and to this great site!
I started by buying a 37 gallon tank (22” deep, minus a few “ of substrate), putting down some carib eco complete substrate, and got planting. My goal has been to do what I guess would be considered a “silent cycle.” Basically I just planted several, fast growing plants, mostly stem plants, and provided them with root tabs and seachem flourish, as directed. I also added a somewhat decent LED light (keeping it lowtech, no CO2, plants only need low to moderate light). It’s been just one week now, and I detected maybe 0.25ppm ammonia, somewhere between 1-5ppm nitrite, and ~5ppm nitrates. I haven’t added any source of ammonia, so I’m thinking that the tank is sort of doing it’s thing with the plants alone? Im wondering if I should do a small water change soon if the nitrites don’t go down and if ammonia climbs? I did also add some API quickstart once I saw those levels, to see if that would do anything to help speed up this process. At this point, if plants continue to grow and if nitrites go down, would it be safe to add just a few fish at first, after a partial water change?
Keep an eye on the stem plants, despite claims on the bag, eco-complete is actually inert. The only fertilizer it had was whatever was in the water in the bag and as you might imagine that goes away pretty quick. So if you plan to proceed with only root tabs be aware you should be replacing those on some kind of regular schedule. Personally I prefer liquid fertilizer all in one product like Nicolg ThriveC or Aquarium Co-op Easy Green. I actually have both in use on different tanks and they both do a fine job for me. As for water changes. You can do one whenever you feel you need it. The plants by themselves can handle reasonably high levels of ammonia, certainly 4ppm won't do them harm. Fish of course are a different story.