I apologize in advance for a very lengthy post... I have a lot of questions.
I have a 29 gal
freshwater community tank, lightly planted. I'm using the Aqueon QuietFlow 30 (200gph) HOB
filter that was included with the tank when I bought it. I have been using the same filter cartridge since I got the tank 7 months ago... I rinse it gently once a month or so in used aquarium water, based on what I learned here.
My ammonia and nitrites are at zero, but my nitrates are 60ppm after a 30% pwc
. I had gotten lazy about PWC
's... which is probably why nitrates are so elevated. I planned to do frequent PWCs and get a lot more plants to fix this issue.
However, one of my friends who has kept freshwater fish for a long time told me that plants won't help much. He also thinks my filter is inadequate. He claims that if I had a second filter, there would be sufficient "room" for de-nitrifying bacteria (the ones that convert nitrates into N2 gas) to grow.
After some research on the topic, I found that de-nitrifying bacteria are anaerobic. I can't imagine how a regular HOB
filter would ever harbor such bacteria. In fact, all the information I read pointed to de-nitrifying bacteria being a marine aquarium thing (there is de-nitrifying filter media for marine aquariums, and also it happens in live rock/sand... I found nothing meant for freshwater). These bacteria can live in freshwater substrates as well, but if they don't get at least a little oxygen, they can release poisonous hydrogen sulfide. Supposedly plants help prevent this... but the possibility of hydrogen sulfide sounds like a serious matter.
So I guess this brings me to my questions regarding filtration: Is my filtration adequate for my tank size?
Will I see an improvement in water quality with a better filter like the AquaClear one I saw mentioned in other threads?
Can any filtration media safely assist with nitrogen removal in freshwater tanks?
How effective are plants at removing nitrates? Is my friend right about more plants not really helping much?
Also, I read that vacuuming gravel is important for nitrate reduction. But I have live plants so it's hard to vacuum without disturbing/possibly uprooting them. In addition, I made the mistake of putting sand on one side of my aquarium (I wanted one side to have a sort of sandy beach look, mostly because I thought my kuhli loaches would like digging in it). This didn't work... the gravel and the sand combined so now I have pea gravel with sand mixed in just under the surface. If I vacuum I start sucking up sand and stirring it all around.
So, given that I will be planting even more heavily than I am already and there is sand in the tank, do I still vacuum? Tips on doing this properly would be appreciated.