Are nitrates really that bad?
In an effort to defeat algae (esp clado) in my 20GL, which has worked (knock on wood) for a few months now with not one spec, I did the following things:
1. wrapped my Finnex 24/7 with screen to mechanically block light
2. stopped changing water every week, now do once a month ~ 40% - I did this because my tap water is high in phosphates. At one point, phosguard eliminated my algae but I didn't want to keep spending on it so I took the strategy to let phosphates deplete, only adding more via tap water when I topped off.
3. added a bunch of anacharis and hornwort (riparian looking tank) to out-compete algae on nutrients. I have some small amount of rotala and green hedge in there too.
I add no ferts.
Right now my tank is over-stocked, I have platies and endlers that are breeding prolifically and am about to scoop a bunch to take to the LFS.
2 adult platies, 6-8 juvies, bunch of fry
7-8 endler adult females
perhaps a dozen male endlers (but they are small)
bunch of juvie endlers and fry
~ 50 RCS
I've been measuring water parms weekly and notice that nitrates have been very high, it hit > 100ppm right before I just did a water change. Before all these changes, when I had bad algae, nitrates would rarely get above 20ppm. Ammonia and nitrites have held at 0. The anacharis and hornwort have been growing so much I have to cut them back frequently.
Here's the kicker though, the fish are all healthy and breeding (as
well as a large pop of RCS) with these high nitrates which they have been exposed to for weeks. And I have not seen one dot of algae which you are supposed to get with high nitrates (been tossing a little invert food in there worried that my nerites and RCS might not get enough food).
I feel like there must be more to the nitrate story.