Water flow in the planted aquarium?

Ady34

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martinmjr62 said:
Ceg, I stand corrected. Does this mean I should run it with or without the diffuser??


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I'd say it all depends on how it's working in your tank with your hardscape and other circulation. If your happy its creating the flow in the right place I say leave it. Return pipes come in all shapes and sizes aimed at creating different flow patterns suited to different situations. If the 'jet' is getting the flow where you need it then happy days. If its too directional then remove it.
Cheerio
Ady
 

geoffbark

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martinmjr62

I think what fox and ceg are trying to say is that without the diffuser the volume of water will be greater through the pipe, therefore turning the tank volume over faster and ditributing the nutrients through the water column :)

You are nearly correct in thinking that a smaller oriface increases water pressure, what happens is actually the volume of water (Flow) decreases therefore the smaller water volume travels with more force. Test this with the garden hose, the pressure on the garden hose does not increase this is set by your supplier (or booster pump) but when you put your finger over the end reducing flow sending the smaller water volume further:)
 

Clifford

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I'm reluctant to appear as a pedant, but what actually happens is an increase in fluid velocity as the cross sectional area of the orifice decreases.

There may be some reduction in flow and pressure, but these will be due to losses from friction e.t.c.

Water is largely incompressible so as the orifice it's travelling through reduces in area the water needs to travel faster to enable the same flow rate to be maintained.
 

geoffbark

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Clifford said:
I'm reluctant to appear as a pedant, but what actually happens is an increase in fluid velocity as the cross sectional area of the orifice decreases.

Correct ;)
 

Daz2162

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After ready this post and being thoroughly entertained but some of the debates, ive has a shift round of my hardware.
Recently i purchased an all pond solutions external filter running at 1000l/ph (so probably 800l/ph) 9w uv steriliser that came with a spray bar that covers just under half the tank length (tank length 60cm), this is positioned with holes facing straight forward pretty much at waters surface. My co2 diffuser is at the back of the tank as close to the bottom as i could get it with a jbl proflow 400 just above the diffuser that picks up the bubbles and throws it at the front which then disperses them around the tank along with the rest of the nutrients. The spray bar is agitating the surface quite nicely, it osnt breaking the water but its moving nicely.
I also run an airstone at night for about 12 hours to help oxygenate the water column whilst the plants arent producing.
Cant seem to get any plants pearling though which is a shame, any ideas how to get them going? Ive got a 60ltr tank, and running 1bps, unfortunately my solenoid is faulty so the co2 is running 24/7, which is why its highly important to run the air stone.

Cheers

Darren
 

ceg4048

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Hi Darren,
Well, frankly, it would be better to not really worry about pearling. Pearling doesn't really mean anything and is in no way an indicator of plant health. Many people chase this idea of pearling and ruin their tank doing so. Just concentrate on getting good flow/distribution,,good nutrition and on keeping the tank and filter immaculately clean.

If you want to understand more about pearling, and why it can be like chasing a red herring, check any or all of the following threads;
Is this a type of algae? | UK Aquatic Plant Society

Plants pearling | UK Aquatic Plant Society

Help I need a scientist! Water changes, pearling and CO2 | UK Aquatic Plant Society

Cheers,
 

Daz2162

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Hi ceg,
Yeah thats a fair point mate, it sounds stupid but id like a visual confirmation that the plants are producing, guess i should just be letting the fish tell me, healthy fish oxygenating plants right, obviously among other things! Now ive moved the hardware around abit to be pointing towards the front glass the distribution is far better than when i had my powerhead side on, time will tell if its being effective as i only made the change last night.
My amazon swords have tiny bubbles on the undersides of some of the leaves but i really cant tell if its a build up of tiny co2 bubbles or o2 seeping out.

Cheers
Darren
 

ceg4048

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Well one needs to be aware that when the lights are on Oxygen is being produced. There is no choice. But as explained, whether the gas appears as a bubble or not make no difference. It's entirely possible to have a higher gas production without pearling than with pearling, because the phenomenon itself is a result of many factors.

Cheers,
 

Edvet

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Ok, i have been reading this and have some questions/remarks. Seeing english isn't my native tongue i might have misunderstood some things.
My filtrationsystem is as follows: the tank has an overflow system, water goes through the filter and is pumped up again towards the tank(via a small overflow).
The 10 times rule: my tank is 400 gallon with app 100 gallon volume in the biological filter. I dont think pushing 4000 gallon per hour wil work:meh: . And to add to that my water drops throught two pipes filled with bioballs (in order to aerate the water and have good biological brakedown) which are app. 150cmx10c0x10cm. I tought all the water will loose it's CO2 there. That combined with a large turnover strips a lot of CO2 from the aquarium. I have troubles getting sufficient CO2 in there as it is. (i ordered 2 spiral glass diffusors from Singapore wich worked well in the past, just have to see if they arrive:( ). I did use a home made diffusor in the past (pvcpipe filled with bioballs at the end of my pump exhaust with CO2 coming in from underside and rising against the flow) wich i will ressurect if the glass ones don't work or don't arrive.
So in order to keep the CO2 in my tank I throttled the pump so i only change some 500 lit/hour. It still goes through the bioballs but the biological filter is largly empty with only some sintered glas pipes (app 10 lit.) in thin layers and some foam. I figure my fish population is so low compared to the volume i dont need large filtering volume, lots of the waste will be broken down in the tank and used through the plants. In order the still have some dispersion in the tank i use a Hydor Koralia circulation pump on and off. I dont use it full time as i always thought and understood surface movement made CO2 escape the tankwater faster, so i try to keep that to a minimum.
After reading the thread i now think about buying a second Hydor and leave both on 24/7.
Comments on my thinking please
 

foxfish

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You will most defiantly loose co2 down the overflow, that is the main disadvantage of having a sump, so your logic is correct in throttling down the flow to the sump.
The simple way to dissolve the gas would be to feed it directly into the return pump, this will however form a mist. You can take it a step further and use a needle wheel pump to return the co2, this will give a very fine mist that lots of people believe to be the most efficient way for the plants to absorb the co2!
I have my internal pumps come on with the gas timer and off with the lights.
 

Edvet

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Did get me a second circulation pump today, i have them alternating and on crossing streams, so i know there is plenty agitation in the tank atm. Not sure yet wether i will leave them on during the night (rivers keep flowing at night i think)or put them on the off circuit. CO2 is on 24/7 anyway.
 

Cherry

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what great threads ! simple question - I have two external filters - a fluval 404 (brilliant apart from the disgusting white attachments) and an aqua something gives me 10 times turnover(both with spray bars
plus a two pumps to circulate water /co2
Would I be better to place my CO2 diffuser under one of the inlets and/or get one of those fine diffusers (however I try and place the diffuser at the moment the bubbles seem to get to the top too quickly
Also,and I hadnt thought of this - should i switch off one of the water pumps at night (although some of my fish seem to delight in playing in the flow!
 

ceg4048

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Hi,
It's always a better idea to try the cheap solution first. You can place a small diffuser under the inlet of the strongest filter and see how it goes. Do the pH profile checks and see how the gas behaves. If you can't get it to work, or for whatever other reason, such as aesthetics, if it doesn't work out then get an in-line device.

I see no reason the turn off pumps if the fish are not in distress from the motion.

Cheers,
 

Cherry

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Just looked them up (better keep these facts somewhere
Fluval sea circulation pump (fish love to play in this - got it for the CO2) -5200 l/ph
Fluval 406 Filter 1250l/ph - just bought this (had an internal in before
Aquaone 1050 filter 1250 filter 1250 l/ph
aquaclearpowerhead with polisher 474 l/ph
crikey its a lot:eek:
my guru at maidenhead aquatics told me "you can never have too much filtration!!
Havent changed sponges in my aquaone for four years (rinse regularly) :geek:

seems to keep the algae at bay(well none really) (that and the CO2 - that ran out when I was on holiday - black hair algae urgh)

have got such high filtration as I want to keep more fish
just upgraded my lights too
 

Cherry

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yea - the aquaone is definitely not belting out its full wack.
The two filters I have spray bars at the back ,so the water sort of rolls in a circular motion round to help with CO2 I found the duck pipes (?) too powerful)
I have the two p umps in the right hand corner - the fluval to try and blow the CO2 about Ceg404(clive?) suggested I put the CO2 under the in pipe but it wont fit:( - the fish love playing in the current
I think I may try an in -line device - where do you get them? (although I may try the smaller fitting first)
 

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