Have I been upsetting the balance?
#1
Ok, this is just a recent observation and I'm looking for opinions.
I've never been able to keep plants alive in my 200l tropical tank. There are not many fish in there now and there is a bit of java fern left that is tied to wood. I have it in my mind that I've read somewhere that if you clean your gravel 'too' well, you can upset your bio filter.
I recently changed the way I perform water changes and now use a pump in and pump out method and haven't hoovered the gravel in 4 weeks. Since I've done this, not only have my nitrates lowered (I've always had a nitrate level around the 50ppm mark despite using nitrate filtered tap water), my java fern has started to sprout a few new leaves. I performed my nitrate test at the end of the week before a water change and it was 5ppm (I did the usual 'bang the hell out of bottle 2' of the API test kit and performed the test as I usually do). I change 30 - 35% in volume per week.
Another thing I've noticed is that I'm getting a lot of green spot algae.
Thoughts?