Flow, Aeration and Fish

[Andy Pierce]

... a dozen embers, who really don't like flow.

What I did (I also have embers) was to add a small powerhead towards the bottom of the tank. That will improve flow around the plant mass and won't bother the embers which prefer being higher up in the water column, or your floating plants.

I'm a big believer in one good tool for each job. If you want flow, use a powerhead. If you want aeration, use an airstone. If you want biological filtration, use a filter. Etc.

 

[_Maq_]

flow through a filter is not as critical as the biological surface area available.

But how do you know your microbes need extra colonization area in your filter?

 

[Bradders]

But how do you know your microbes need extra colonization area in your filter?

What do you mean exactly? Do you mean how do you know if you have enough good bacteria built up on the filter media surface?

 

[_Maq_]

What do you mean exactly?

I think that biological filtration is redundant in planted and modestly stocked tanks. You say that colonization area in the filter is important. So I wonder haw did you come to that conclusion? Microbes without a big filter did not work?

 

[Bradders]

Ahhhhh, I think I understand your point! And I think you could be very right in your example. i.e. planted tank and a small amount of fish.

However, I don't (really!) have a planted aquarium, and my 100L aquarium is more moderately stocked than modestly, with 40 inches of fish. (See the really poor picture below, don't laugh!!) So, to keep the water healthy, I need effective 'artificial' filtration. And I don't think my aquarium/bio-load will survive in its current configuration unless the filtration is good. i.e. there are not enough plants, and the soil is just gravel, which will not replace the surface area provided by the filtration.

 

[_Maq_]

See the really poor picture below, don't laugh!!

I can see your plants feature signs of iron deficiency. Most likely. (Possibly magnesium or manganese.)

to keep the water healthy, I need effective 'artificial' filtration

Possibly. But consider this: Livebearers create lots of feces. The filter sucks only minor part of them. Most end in the gravel. And there, only there they get decomposed by microbes.
You could also look at some pics posted by @dw1305, taken in water processing plants. There is no "colonization area" there. The activated sludge ("the dirt") is the colonization area itself. And because the load is extreme, vigorous aeration is necessary. Nothing else.

 

[Bradders]

I can see your plants feature signs of iron deficiency. Most likely. (Possibly magnesium or manganese.)

Thanks, @_Maq_ - yes, I agree, and I am taking some steps to improve this thanks to you and others on this forum. Plant care is certainly a much-needed learning curve for me!

Possibly. But consider this: Livebearers create lots of feces. The filter sucks only minor part of them. Most end in the gravel. And there, only there they get decomposed by microbes.
You could also look at some pics posted by @dw1305, taken in water processing plants. There is no "colonization area" there. The activated sludge ("the dirt") is the colonization area itself. And because the load is extreme, vigorous aeration is necessary. Nothing else.

No, I do think you have a great point for some environments. However, I can't really have such vigorous aeration in my aquarium - certainly nowhere near what DW1305 demonstrated in his processing plants post, as the fish will pack their bags and find a new home. I appreciate that I could test this, but I am not confident that turning off my external filtration will be sufficient to keep very clear/clean/healthy water at this point in my environment.

 

[_Maq_]

We don't need that vigorous aeration because the load in water processing plants is much much higher. But yes, water flow is essential. It doesn't have to be as strong as it would make fish suffer.

 

[LFNfan]

Took me a while to spot it but loving the police call box!
Your spray bars (and tank in general) are so clean... wish mine was that clean

 

[dw1305]

Hi all,

I can see your plants feature signs of iron deficiency. Most likely. (Possibly magnesium or manganese.)

I think they do <"Cloudy Water Hazy Water and Algae!">.

You could also look at some pics posted by @dw1305, taken in water processing plants. There is no "colonization area" there. The activated sludge ("the dirt") is the colonization area itself. And because the load is extreme, vigorous aeration is necessary. Nothing else.

Yes, I've been lucky enough to visit a lot of <"water treatment works"> (and <"landfills">), but this is the photo @_Maq_ has in mind <"First Planted Tank - 180L"> .

Photo by John Rostron, CC BY-SA 2.0, <File:Beckton STP, Activated Sludge Tank - geograph.org.uk - 1481906.jpg - Wikimedia Commons>

While they aren't the places fish-keepers would (or could) visit they are extremely interesting and they let you differentiate between what is important (<"basically dissolved oxygen">) and what isn't. Add in some plants? and things improve again <"How Floating Wetlands Are Helping to Clean Up Urban Waters">.

cheers Darrel

 

[_Maq_]

the police call box!
Your spray bars (and tank in general) are so clean...

That's thanks to the police being on spot; underwater criminals stand no chance!

 

[LFNfan]

A bit like @Andy Pierce said, I use airstones left and right for surface movement (blue markup) to promote gas exchange.

I use the filter outflow to move water around the tank in a circular way - outflow goes across the front of the tank at mid-height (green markup) and the intake pulls water from back mid-left (yellow markup). It's more or less circular anyway.

Your twin spray bars are pushing water from the top back to to top front, getting your surface agitation but im not sure how the water is moving around the tank.

 

[Bradders]

Your twin spray bars are pushing water from the top back to to top front, getting your surface agitation but im not sure how the water is moving around the tank.

Good point. I made a slight adjustment to try and get the best of both worlds. I have one output from the spray bar (which should also bounce off the front and create some flow), removed the second spray bar and replaced it with a nozzle pointing into the tank more. The plants seem to be moving a very slight amount - very light sway in the water.

Also, would you guys call that surface agitation good for gas exchange? (Turbulent and not laminar flow).

 

[Tim Harrison]

I’ve read some of the thread but not all, so not sure what’s been said. But there isn’t much need for excessive flow in a low-energy system. Except perhaps for good surface agitation to maintain O2 and CO2 levels.

Regarding a redundant filter for a new tank, just keeping them ticking over at a lower flow rate will be fine. Filter manufacturers often recommend controlling flow with the output valve.

The generation period of nitrifying microorganisms is measured in hours. They reproduce by binary fission so will rapidly adapt and change to the environmental conditions. A viable colony is all that’s needed.

 

[_Maq_]

there isn’t much need for excessive flow in a low-energy system. Except perhaps for good surface agitation to maintain O2 and CO2 levels.

Recently, this question arose my interest and I don't take it for resolved. I think of some borderline situations where improved flow might have helped. (I consider acquiring stronger internal pumps.)
Obviously, it's difficult to communicate our preferences with measuring flow in terms "slow", "moderate", "strong" etc. What is "moderate" water flow?

 

[Tim Harrison]

For sure @_Maq_ . There are no absolutes, every tank is different; there is always more than one route to success. For instance, I like to stick to the x10 turnover rule (x10 the volume of the tank per hour), even low energy. But x5 usually suffices very well. However, I’ve successfully run low-energy tanks with a lot less.

 

[Andy Pierce]

Obviously, it's difficult to communicate our preferences with measuring flow in terms "slow", "moderate", "strong" etc. What is "moderate" water flow?

We could base this on how the plants look. 'Strong' is detectable movement/motion in all plants, 'moderate' is detectable movement in many plants but with some quiet regions, 'low' is some detectable plant movement but most plants are still.

 

[Bradders]

I think they do <"Cloudy Water Hazy Water and Algae!">.

I can see your plants feature signs of iron deficiency. Most likely. (Possibly magnesium or manganese.)

Thanks, @dw1305 and @_Maq_, for the plant advice. Much appreciated, as always. I have taken steps to address this, starting with APT Complete, dosing at 1mg per day as per their website calculator. (I have no C02). However, it raises another question: whether I also need to add root tabs, or will the liquid fertiliser on its own be enough to actually make a difference over the coming months?

 

[_Maq_]

whether I also need to add root tabs, or will the liquid fertiliser on its own be enough

Sorry, I've forgotten what your water (mineral content) looks like. Depending on that, you might need strong iron chelates.
In my country, some vendors sell iron root tabs. These might be helpful for you. I don't use them but when establishing a new tank I usually add powdered iron oxide to the very bottom, and it seems to deliver good results. Even iron nails buried in the substrate are probably helpful.

On a different note: Do I detect correctly Ophiopogon at the left side of your tank? This species is generally considered unsuitable for submerged cultivation.

 

[dw1305]

Hi all,

whether I also need to add root tabs, or will the liquid fertiliser on its own be enough to actually make a difference over the coming months?

I'm not sure root tabs make any <"positive difference">, but I don't tend to break my tanks down and, <"over time">, the "normal" <"substrate processes"> will occur.

On a different note: Do I detect correctly Ophiopogon at the left side of your tank? This species is generally considered unsuitable for submerged cultivation.

I think it is <"Ophiopogon japonicus"> as well, unfortunately one <"that comes up a lot">.

i rang them up and they are selling it as fountain grass (ophiopogon japonicus). Not an aquatic, but can apparently do ok in aquariums with enough light and nutrients. We'll see how it goes.

We live in a post truth world. Ring them back and tell them that it isn't a plant that can ever grow underwater, and that you are very disappointed with the advice you have received. Unfortunately you need to remove it asap. It is fine as a house plant, it is not fine as an aquarium plant.

cheers Darrel