Biological Filtration

[jewels]

As things are my 75 Gallon {Fluval 405 + 2 powerheads} will consume about 85 ppm of Nitrate each week. If it is the plants enjoying the N; then great !

At he same time - how much KNO₃ am I adding simply to support the 405 ?

If my 405 is hogging Nitrates it seems silly to pay for dry ferts and electricity just to rob my plants :bang1:

Kind of a scary leap but, , , If I had enough plants in an aquarium could I skip the media holding filters and switch to power heads only?

Anyone try it ?

[Wingin' It]

I'm pretty sure you can. Fleshgear has a similar set up. Can't remember what he called it, but there's enough plants in there to keep things healthy.

[Vallisneria]

Maybe i'm missing something but why would your Fluval be using Nitrates?

[Baos]

I recommend you buy this book immediately! http://www.amazon.ca/Ecology-Planted-Aquarium-Diana-Walstad/dp/0967377315

You have a lot to learn and this book could be your new Bible. Plus save you future headaches.

[Kronosdelsol]

Vallisneria is right. The plants consume the nitrates and its the filter's good bacteria that converts the harmful nitrite (NO2) into nitrate (NO3). We do water changes to remove nitrates, but in a planted tank you don't need to. Unless of course you are over dosing the nitrates and it is affecting your fauna. Water changes are good, unless you are going El Natural. Lost everyone yet?

Yes you should be okay without a filter. You only need it for mechanical filtration. Many people have success with it as long as you have a low fauna community and semi amount of plants. Rhonda Wilson popularized this. I had no filter or way of moving water in my tanks for a long time. There was no problem assuming you have a low fauna population.

Diana Walstad's book is a good read but not for everyone. She offers a low tech setup which uses low light, mineralized soil substrate, no water changes, low fish population. You would also be limited to certain plants. Some people have success with it, others don't.

It ultimately comes down to how your plants are currently getting their nutrients and how fast you want your plants to grow and look. Maybe provide more details on your setup.

Edited April 17, 2010 by Kronosdelsol

[werner]

Your filter won't be hogging nitrates. Of course, nitrates are the end product of the biological filtration process, so I'm guessing you mean nitrogenous compounds in general.

The plants prefer to get their N as ammonia/ammonium (more efficient to process than nitrite or nitrate.) Since they'll be using it directly from the fish, there will be little (none?) available for the filter bacteria, and the colony is limited. With enough healthy plants, your filter will be used mostly for mechanical filtration and water movement.

[jvision]

On a well planted tank, you don't need a lot of biological filtration. However, I have found that if you have a good amount of biofiltration available, your chances of Green Water in a planted tank are quite low. Your plants will be consuming as much NH3 and NO2 as they can, but will leave a small amount for the filter. And, the NO3 the filter does produce will be consumed by the plants. My tanks have too many plants and don't get enough N from the biological processes, so I add some a few times per week.

[jewels]

Great replies, thanks folks !!

Despite my misdirection , you got the jist of things

Your plants will be consuming as much NH3 and NO2 as they can, ,,,. And, the NO3 the filter does produce will be consumed by the plants.

This quote sums up my glaring faux pas.

I am adding all this KNO₃to compensate for the lack within the water. If the 405 was not converting this Ammonia and Nitrite would there not be more available for the plants?

To rephrase

• Is my Fluval hogging Ammonia and Nitrite that would otherwise be uptaken by my plants
  
• without the fluval could I get away with adding less KNO3 ?
  

48 inch 75 gallon

6 inch substrate :exspanded clay ( AP.com & Shultz's pond ), prehistoric peat, zeolite, worm casings, spahgnum peat

400 watt Ushio 5500K metal Halide & 6 X 20 watt 6500K T4 for 12 hours/day

adding 5 grams of KNO₃ everyday ( considering increasing)