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Water flow in the planted aquarium?

darren636

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could you not angle the outlet diagonal downwards? That should keep all the water moving.
 

hudsonpd

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Anyone got any advice as to how wide apart the holes in a spray bar should be? And how frequent they should be?

Ceg, with all of your experience, how will this impact the velocity?

My tank is a 1m long and 50cm deep. I have a FX5 filter which I am going to fit a spray bar to.

Will this get the CO2 to the bottom ok and also through the plants to the back? I am a bit concerned I get this wrong either because the velocity reduces too much along the bar or because the tank is too deep for the flow to get the bottom and then to the back,

Ceg, how deep are your tanks?
 

ceg4048

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Hello,
Velocity is the servant of mass flow rate. The purpose of flow and distribution is to move large masses of water not only to carry away debris, but to bring new water with high concentrations of nutrients and CO2 towards the plant, because the leaves will absorb the nutrients in the surrounding water and will deplete the volume of water within their immediate vicinity. Moving the water brings fresh supplies and reduces the thickness to the stagnant area adjacent to the leaf. You don't need high velocity but you need high mass flow rate because there is a lot of water to move, which is distributed over a wide volume.

The spacing and number of holes in your spraybar is determined by your tubing ID and your length of spraybar. There is no fixed distance or size that you must adhere to, but what you should do is to ensure the the total amount of surface are of your holes combined should be greater than or equal to the cross sectional area of the spraybar ID. So a good place to start is the calculate the area and then pick a number of holes. That means each hole must have a certain size and those holes will be distributed evenly across the length of the spraybar. Of course you make room for fittings and other sundry issues, but that gives you a start. If you calculate a spacing or number orf holes that is an absurd number then reiterate the procedure and re-do the calculations, this time picking a different number of holes or hole size.

Different things can go wrong when you test the bar. It might be that the flow rate from holes at the beginning is different that the flow rate at the end. If the holes are too small they water might be too high a velocity, of the holes too large the jets might not quite reach the front glass. So you have to play with enlarging the holes or modifying the length of the bar. Use a few pieces of PVC with different drilling and hole patterns to get it just where you want it. Also note that you don't have to chock the filter full of media, you can use half as much media, which will improve your flow rate. Some people enlargen the holes if they fell that the velocity is too strong, and this works just as well so don't worry too much. I just show as a general rule of thumb to try and get the jet streams to make it to the front glass, so you do need to experiment a bit but PVC is relatively cheap (in most countries anyway).

My largest tank is around 60 cm deep and I didn't have any difficulty at all when adhering as close to the 10X rule as I could. Make sure that you do not reduce the tubing ID too much with reducers and so forth along the water circuit.


Cheers,
 

martinmjr62

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Hi after reading this thread I'm still unsure of what to do about the flow in my tank. I have a jewel rio180 running a Fluval 405. There is a full width double spray bar across the back pointing slightly up causing a ripple. The plants in the centre are moving but the plants on the right hand side and back right corner se to be stationary. To get the co2 flowing around better I've considered getting a koralis power head. The problem is which size. The flow rate on the Fluval is rated at 1300l/h but the manual says that loaded up its probably around 850-900l/h. So should I get the nano 900 which puts out 900l/h or the bigger 1600. The rule of 10x flow would suggest to get the 900,combined with the Fluval would basically give the required 1800 l/h, or should I get the1600 which would give me around 2500l/h total flow ,possibly too much.

Any advice please
Thanks
Martin


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LancsRick

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If it's a single filter, where is your intake? My money would be on the fact that you're setting up a biased flow because you're only drawing water from one location in the tank. Think of the flow as a circuit - everything going ONTO the track has to be able to complete the loop and get OFF the track. That's one of the reasons I like to run two filters on my tanks, it gives you a bit more flexibility when designing your flow.
 

martinmjr62

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Point taken. But with a limited budget, another filter at the moment is out of reach,so the thought process of a power head was a cheaper option to improve flow so the question was which one would be more suitable


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foxfish

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The problem with power heads & spray bars combination is... where do you point the powerhead?
The idea of a spray bar is to cause a circular motion within the tank, you dont want to interrupt this vortex.
The best option is to increase the flow through the spraybar & make sure it is full length of the tank.
 

Ady34

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Hi Martin,
yeah ideally you would use a larger flow rate filter through the full length spraybar to get an even flow pattern with enough umph to create a good overall circulation. The problem with adding a single powerhead/circulation pump (as Foxfish said) is where do you position it to get an even flow pattern?....you cant really with a rear panel spraybar.....you could buy 2x 900 lph koralia nano's and place one at either end of the spraybar pointing towards the front panel, but again this will be getting more expensive, but if its within reach financially that will be the best compromise and will give more versatility in the future.
Cheerio,
Ady.
 

martinmjr62

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Hi Ady, I did think about putting 2 900's either side of the bar I can an get 2 on eBay for £50. Is that not too much flow though. When do you use them, constantly or only when the Co2's running?
I do have an old Eheim canister filter in the shed. It's a 2213 with a 620 l/h output. Would this be enough flow. And what about introducing another new filter at this stage, would that not mess around with the levels of ammonia/ nitrite. Also been thinking of getting some shrimp and otto's to help with the diatoms algae. I've read that you should get Caridina Japonica, but I've only heard of people getting Caridna Multidentata (amino). Which ones are more suitable. Still a learning curve:)


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Ady34

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martinmjr62 said:
Hi Ady, I did think about putting 2 900's either side of the bar I can an get 2 on eBay for £50. Is that not too much flow though. When do you use them, constantly or only when the Co2's running?
I do have an old Eheim canister filter in the shed. It's a 2213 with a 620 l/h output. Would this be enough flow. And what about introducing another new filter at this stage, would that not mess around with the levels of ammonia/ nitrite. Also been thinking of getting some shrimp and otto's to help with the diatoms algae. I've read that you should get Caridina Japonica, but I've only heard of people getting Caridna Multidentata (amino). Which ones are more suitable. Still a learning curve:)


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Hi,
well, 2x 900 lph plus the 405 may make the tank like a washing machine :lol: Im not quite sure why the plants in the middle of your tank are swaying but not the ones at the ends. Is the spraybar full length or slightly short? Or is there hardscape in the way preventing good circulation? Maybe its just down to the underpowered fluval as 180 lites really needs somewhere near 1800lph for 10x turnover. I used to only run my koralia when the c02 was on to give good circulation, but i now just leave it on permanently as i use it for surface agitation too.
Personally if you already have another canister filter the simplest and cheapest option for you would be to add that alongside the current 405 filter which will up the overall turnover to somewhere near 10x. Id use another spraybar configuration, you could maybe look at 2 shorter bars (one for each filter, perhaps 2/3 length for the more powerful 405 and 1/3 length for the eheim). This way you wont need to worry about seeding the new filter as you already have a fully mature one running :) You also get the benefit of long term of having 2 mature filters (helps when cleaning bio medias), or even running the eheim without any filter media to maximise flowrate to help with your circulation issue.

Amano shrimp are the most efficient algae eaters, and ottos are great also. More info on the set up will help determine what you need to do as generally speaking you can eliminate algae issues with lower light, good c02, frequent large water changes, good dosing regimes and of course good distribution via circulation.... all of these help the plants flourish and then the reduction of algae.

Cheerio,
Ady.
 

martinmjr62

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Hi Ady, the set up is as follows
Jewel rio 180 1000x 400x400
Fluval 405 with spray bar across the back. Spray bar is 800 long
JBL 2 kg CO2 injection from 11am to 7pm via glass diffuser under the spray bar
Drop checker showing yellowy green when lights on
T5 lighting from 1pm to 9pm
There is a large tree root to the right side which could be slowing the flow down to that corner



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martinmjr62

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Forgot to add water changes are twice a week@ 50%
Dosing macro an micro ferts on alternate days starting Sunday and stopping Friday


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martinmjr62

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Latest news. I've dug out the old Eheim thoroughly cleaned it ,loaded it up and put it on the right hand corner. I've decide to leave the full spray bar running on the Fluval and have fitted a small diffuser to the end to force the water into a smaller outlet to increase the pressure. The outlet is pointing straight into the front right hand corner and the movement of the plants on that side has now greatly increased. Didn't cost anything either which is a bonus and extra filtration must surely be better. Hopefully going to get some amano shrimp and some otto's tomorrow if I get out of work early enough


e3a8azed.jpg




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martinmjr62

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foxfish said:
I would think that the diffuser you have fitted will dramatically reduce the flow potential, just try it without & see what happens?

The flow seems very strong. All the plants to the right are swaying nicely. Without the diffuser it did seem slower. Forcing the water through a smaller outlet increases the pressure.


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ceg4048

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No it doesn't. Smaller orifices decreases the pressure but increases the velocity. This is fundamental.

Cheers,
 

martinmjr62

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


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