Flow in a jungle tank

[jameson_uk]

I will post a video tomorrow but wanted thoughts on flow in a jungle tank. My tank has grown out and is now quite densely planted.

After lots of experimentation I ended up with the spray bar along the short side of the tank and a flow pump in the far bottom corner.

This has worked well for most of the tank but the opposite corner to the flow pump (back corner under the spray bar) is not doing so well. There is a really dense crypt which has developed quite a bit of GSA and some Bacopa behind it which is really struggling with the lower leaves which are dying off when the upper leaves are doing OK. The back corner is also a bit of a trap for detritus in the back corner.

I believe issues come down to flow as the rest of the tank is doing OK.

Now I guess the normal response would be to out the spray bar along the back glass but when I did this it ruined my frogbit, squashing it all against the front glass.

My thoughts were that an airstone in the problem corner might help? Failing that the only solution I can think is adding a tiny powerhead (I have an Oase one which goes down to something like 150lph) to just push the water through the crypt.

Any tips on improving flow in this situation.

 

[Bart Hazes]

Is there any chance it could be light rather than flow. Corners tend to be darker and if there are other plants in front the lower parts of plants in the back are in the shadow. One option is to plant the darker corners with slow growing low-light tolerant species and have fast growing bacopa closer to being vertically below the light source. Heteranthera zosterifolia and Eichhornia diversifolia (the latter often described as a light-hungry plant) are growing well in low light conditions in my tanks. They may not be as robust and dense as in high light but bottom parts are not dying off.

 

[roadmaster]

Spray bar mounted on back glass should have little affect on floating plants if mounted under the surface a few centimeter's.
Would only shove plant's to the front glass if mounted very close to the surface, and then they(plants) would split and gather on either side of the tank rather than at the front.
Course this would result in plant's under floating plant's not getting as much light on either end of the tank.
Does create best dispersement of gas/nutrient's IMHO

 

[Edvet]

I would start with the spraybar along the backwall to see if that works. In the meantime you could keep the frogbit in a separate container to keep them alive. Gradually lower the spraybar while keeping the good flow and after that add frogbit again.

 

[jameson_uk]

Is there any chance it could be light rather than flow. Corners tend to be darker and if there are other plants in front the lower parts of plants in the back are in the shadow.

The problem I have with light is there is too much! The stock Juwel lights are 2 x 45W T5HO tubes which have required me to tweak the layout to try and reduce the amount of light hitting some plants.

I think it is flow for a number of reasons (but I am often wrong )
Before the plants grew out the Bacopa was doing OK and was growing well for several months.
The crypt didn't have any GSA until it grew quite thick and the worst areas were those with lower flow due to the amount of leaves (the crypt is right under the light)
I have some Limnophila sessiliflora in the tank which is doing OK in that corner and my understanding is that this will grow leggy in low light (as I had it when growing under a patch of Frogbit) and so far it has remained relatively bushy.
I can physically see the sway of leaves decreasing as the plants grow thicker.

Still not had time to take a video / pics and each time I get time (It has been a month since I started this thread) it is always after lights out so don't want to start messing around.

Will look at the other plants you mention anyway

 

[jameson_uk]

Spray bar mounted on back glass should have little affect on floating plants if mounted under the surface a few centimeter's.
Would only shove plant's to the front glass if mounted very close to the surface, and then they(plants) would split and gather on either side of the tank rather than at the front.
Course this would result in plant's under floating plant's not getting as much light on either end of the tank.
Does create best dispersement of gas/nutrient's IMHO

There are videos of how I had the spray bar originally
Spray Bar Flow
but the tank has grown out a lot more now and now looks more like

But I did a fairly big trim of Anubias and thinned the frogbit quite a lot last weekend

So are you saying to have the spray bar pointing straight across a few cm below the water line?
If I do this will I get much surface agitation?
Previously I had the spray bar under the surface but pointing up at it and this caused issues.
With the length of the frogbit roots though even a few cm under the surface seems to move them about. (There is a little powerhead in the front top right corner that I use to push the frogbit around every so often so I can clear out any build up of rubbish that is accumulating there)

Just remembering that I struggled to keep the frogbit anywhere where I wanted it (Particularly over the Anubias and wood)

 

[ceg4048]

Hi,
Nice tank.

The problem is exacerbated by the fact that the spraybar is pointed towards the long axis of the tank, so it's difficult to move the water along that distance and to have it return along the bottom with any kind of coherence.

Generally, the best depth is just under the surface. This pulls the surface water along and creates the ripples which helps with gas exchange.
Also, the roots of the floating plants are acting as a speedbrake and so they affect the flow pattern.
As you noted, it was easy to get away with this when there was much less biomass, but as the mass increases, so does the CO2 demand and the added mass blocks flow, so this is a double whammy.

my understanding is that this will grow leggy in low light

This is not why plants grow leggy. Legginess is due to poor flow and this typically happens when the plants are initially flooded.

Cheers,

 

[roadmaster]

Would want spray bar mounted on back glass ,not the ends, and point holes towards front glass.
Nice sterbai corydoras by the way.