From my (limited) experience, if you have a lot of plants it wont
necessarily remove nitrates. Think of it as a recipie, you need ALL the
nutrients for plant growth for the plants to use the nitrates. In other
words, if you dont have enough of one nutrient then the plants wont look at
the other ones cos they need them all. Kind of like a nutrient bottleneck

I think for any noticable nitrate reduction due to plants you need some
really fast growing plants. Ive got some plants in my tank that seem to be
growing an inch every day or so. I use co2, 11 hours of light a day, trace
element fertiliser and potassium. Check out the krib website for fast
growing plants and a way to do a nifty little co2 system for a few
dollars/pounds

Mark

"Paul" wrote in message
om...
How many plants do you need to put in an aquarium to make a
significant dent in nitrates?

We all know plants use nitrates as a food source, but I have 4 potted
plants in my 20-long aquarium and the nitartes do not seem to be any
less. Is it that I need to put a truckload of plants in there to
reduce the nitrates or what?

Right now only my monthly water changes do anything, and I'm not
looking for a way to stop doing water changes, it's just that I don't
want them getting too high because it promotes algae and is bad for
fish.

Frost