Water flow

[DukeNJ]

Hi everyone,

I currently have a 80g planted tank that is doing fairly well for a first tank. I am upgrading to a new filter after running into a deal on an Eheim 2076 that was too good to pass up. I was never happy with the system that I inherited with the intake and spraybar positioned adjacent to each other. Though I see that a lot, it doesn't seem optimal.

When the new filter arrives I'll be reconfiguring and thought I;d ask about optimal flow models in an aquarium.

Intuitive to me is to have intake and outflow at opposite ends of the tank and physics will require flow through the tank. Given that there may be some deadspots due to plant density and decorations. I understand the need to get adquate dispersion of co2 and nutrients in general. Though I always thought that natures find equlibirum and that dispersion would happen with any degree of water movement in a closed system.

I've been reading a lot on the various sites to determine what is best - a lot of forceful flow, or minimal flow. Seems the majority of opinions recommend over filtration and lots of flow to ensure no dead spots. I even read one post in which the writer insisted that you need a lot of force over the substrate in order to prevent settling of detritus so it can be filtered out of the system. Those points are contrary to much of what I have read in books (not that there are a lot of books on the subject) that low flow is best for planted tanks. This site has the first mention of a study on the impact of flow on plants, suggesting that too much flow inhibits, or causes leggy growth patterns.

Seems many methods work, but since I'm reconfiguring, I thought I'd poll opinions here.

So what do the experts here think - forceful flow, dispersed flow, spary bars vs jets vs lily pipes?

Looking forward to the discussion.

Thanks,
Duke

 

[Philosophos]

Even, steady, current is what I like. I try to get at least a couple sources of current from different angles to get distribution where I need it. Much like lighting, high current from one direction aimed in one place isn't going to provide for the entire tank.

I find high current low in the tank does reduce mulm when it's coupled with good filtration, but not without that element.

Books are not necessarily better because they are published. Unless you go to the right sources, the ones commonly available don't even receive enough attention to have anyone attempt to refute them. I've found the dialog offered on forums, and good scientific research has brought me much farther than books.

-Philosophos

 

[DukeNJ]

I agree about books Philosophous. And magazine articles. Many are informative, some seem lazy. If I had a dollar for every time one mentioned the 2 watts-per-gallon rule without mentioning the variances and deltas for each type of light I could buy a new system.

Duke

 

[Steven]

Same here, I am struggling with water flow or circulation in my tank too. The CO2 indicator already in yellowish green color and I've bought myself a 900lph canister that stated to suit the tank of 100-150 liters and mine is 96 liters (80x30x40), yet most of my plants don't do well. One day they grow well and pearl but the other day they just grow leggy and don't pearl. What a frustrating hobby.

Anyway, I will add another powerhead to help increase the circulation to see if it helps or not and I like to ask too if any of you ever use powerhead to help disperse the CO2 bubbles from glass diffuser into even smaller bubbles or as long as there's enough flow in tank, the way the glass diffuser doing its job is fine?

DukeNJ, is the way the lilypipes outflows the water really different compare to other brand? Say my JBL has wide jet form outflow, is it any good? Thank you very much.

 

[DukeNJ]

Hi Steven,

I don't have a lily pipe and can;t speak from experience. What I have read is that they permit a large volume of water to be moved while avoiding forceful flow and minimzing surface agitation. Think of it as running your garden hose without a nozzle as opposed to with a nozzle (standard outflow).

If you think you have flow issues, you may want to try adding a custom inflow/outflow accessory like this one: Aquarium Water Movement: Lifegard Aquatics Customflo Water System

That might help you direct flow around the tank instead of adding powerheaeds. Sounds like you have plenty of flow for a tank your size.

I wish I could give better advice, but there seems to be little input on this topic from the forums. Maybe its simple and we just think about it too much.

Duke

 

[Steven]

Yes and thank you for the link