Astex

I have devoured the threads and what I have learned explains how my fish survive my benign neglect of my main tank (lots of plants).

I will buy the book as soon as the paycheck comes but until then, I have noticed that most everyone has their NPTs with limited flow. I assume this is because the low tech approach is part of the appeal of the system.

I was wondering though, is there any reason you could not have a decent current going in an NPT? I want a bigger tank for my loaches and was thinking of the possibility of a combined NPT/river manifold setup? It wouldn't be a really strong current, but enough to give the fish something to play with.

I would envision lots of vals, anubis, ferns, and a sword or two for the ground with lots of floating plants to make up the extra plant mass and to provide shade for the fish.

Anyone see any major problems with this?

Bridget

Jane in Upton

Hi Bridget,

well, one of the reasons NOT to have strong flow is that it is usually accompanied by significant surface agitation. Surface agitation will promote CO2 to dissipate from your system. CO2 buildup from the bacterial activity (decomposition) on decayed plant material and substances in your soil underlayer are beneficial to your plants. You'll want to keep that elevated CO2 IN the system to get utilized, rather than bubble it away. The use of bubble walls, aerators and such (unless you have a situation where the fish need the added oxygen made available with an airstone/airpump) is generally seen as unnecessary, and possibly detrimental.

A small current, often contained beneath the water surface is beneficial to blend temperature gradients and distribute nutrients derived from fish waste processing throughout the water column. A popular setup uses a mechanical filter powered by a submersible "powerhead", placed beneath the water surface to minimize surface agitation.

Floating plants have the "aerial advantage" in that they will be able to derive CO2 from the air, rather than from the water. As long as they don't shade the fully aquatic plants too much, they should be fine. Floating plants can easily provide too much shade, as they will grow much faster than the plants in the substrate. As long a you're willing to keep their numbers reasonable with culling, they should be fine.

HTH,
-Jane

Astex

The intent is to have the stronger current only 4-6 inches off the substrate. I am hoping this will limit the amount of CO2 loss through the surface agitation.

I don't like dark tanks, so the floaters would be culled frequenty. My current tank has some floating plants anchored 1/2 up the depth of the tank which works fairly well in keeping light availalble and healthy plants.

Thanks for the thoughts.

dwalstad

That sounds fine. It will help keep a soil substrate less anaerobic, promote decomposition, and keep fish safely oxygenated. If the soil is highly organic, the extra oxygen will promote decomposition, releasing even more CO2 for plants.

Let us know how it works for you!