Spray bar or nozzles?

[Steveyg81]

Hi all,

Iv currently got an eheim 2217 running on my vision 180 with the spray bar on the side of the tank. Iv managed to get hold of the outlet nozzle from an fx5 (the two nozzles at 90 degrees).

Would this be better for circulation than the spray bar?

Are there any advantages to having nozzles?

My tank is moderately stocked, with a mound of bogwood on one side.

Many thanks

Steve

 

[Alastair]

Hi Steve,
The fx5 outlets would drastically reduce your flow as they are meant for almost 2000 litres per hour of flow.


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[Ed Seeley]

Hi Steve,
The fx5 outlets would drastically reduce your flow as they are meant for almost 2000 litres per hour of flow.

Why would larger outlets reduce the flow? They may reduce the velocity of the outgoing water but if there is less resistance there is less head and therefore more 'flow' (water moving through the filter) but at a slower velocity. You can't get something for nothing and any restriction you have on filter pipework may increase the velocity of water but it is at the expense of the volume flowing through that point. It a bit like putting your thumb over the end of a hosepipe except a filter isn't high pressure like the mains and the water will stop if you put your thumb over the end!

The other consideration will then be does your spray bar spread the flow out more evenly than nozzles or do you get better results with nozzles pointed at areas where the flow is needed, but this will depend to a large extent on your tank's layout and size.

 

[andrejacobs81]

I have a Fluval 306 (in a 110l tank) and changed from the duck beak nozzle to a spray bar to get better surface agitation as well as better circulation. My tank develops nasty brown string like Algae as soon as the circulation takes a dive.

I currently have the problem where as the filter's output starts decreasing (which isn't always that easy to spot) because of needing a clean, there is less agitation and thus less oxygen entering the aquarium. Woke up one morning to see all my fish gulping at the top for air and lost one rummynose. The tank is not overstocked but I think the plants have grown a bit too much and this combined with CO2 injection (not even reaching a shade of green) caused issues if I am not vigilant on making sure enough o2 enters.

I have now ordered a Hydor Koralia Nano 1600 (to replace airstone + noisy airpump) to ensure that there is enough gaseous exchange happening 24/7 whether or not the filter output goes down a bit (and not having airline pipes shooting off) or not.

 

[Alastair]

Hi Steve,
The fx5 outlets would drastically reduce your flow as they are meant for almost 2000 litres per hour of flow.

Why would larger outlets reduce the flow? They may reduce the velocity of the outgoing water but if there is less resistance there is less head and therefore more 'flow' (water moving through the filter) but at a slower velocity. You can't get something for nothing and any restriction you have on filter pipework may increase the velocity of water but it is at the expense of the volume flowing through that point. It a bit like putting your thumb over the end of a hosepipe except a filter isn't high pressure like the mains and the water will stop if you put your thumb over the end!

The other consideration will then be does your spray bar spread the flow out more evenly than nozzles or do you get better results with nozzles pointed at areas where the flow is needed, but this will depend to a large extent on your tank's layout and size.

Thats what I meant that they'd reduce the velocity of flow


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[dw1305]

Hi all,

I currently have the problem where as the filter's output starts decreasing (which isn't always that easy to spot) because of needing a clean, there is less agitation and thus less oxygen entering the aquarium. Woke up one morning to see all my fish gulping at the top for air and lost one rummynose. The tank is not overstocked but I think the plants have grown a bit too much and this combined with CO2 injection (not even reaching a shade of green) caused issues if I am not vigilant on making sure enough o2 enters.

This can be a real problem, it is more to do with the flow speed of the water than the plants, although they are contributing to the bioload when they are respiring at night. If you have your CO2 on 24/7, even with an air stone CO2 levels can build up.

I wrote an article that covers "Aeration and dissolved oxygen in the aquarium" <http://plecoplanet.com/?page_id=829>, it was intended for plec keepers, but it is relevant for any fish with a high oxygen demand (like Rummynoses).

Can you fit a pre-filter to the filter intake? the advantage of this is that they are really quick and easy to clean, meaning that you only have to open the filter and clean the pipes every couple of months. I use a DIY sponge, but you can get a pre-filter from Eheim etc. Eheim is "part 4004320"

Sponge:


cheers Darrel

 

[andrejacobs81]

Thanks for the nice article. Yeah a lot of people new to the hobby make the mistake of thinking that an airstone pumps o2 into the aquarium when in fact it is all just about agitating the surface to get better gas exchange.

The pre-filter is certainly an idea, it might reduce the flow of the filter but at least then I don't have to clean the external filter with almost every weekly water change.

 

[Steveyg81]

Some real food for thought here, I get pretty reasonable circulation with my spray bar, but there is quite a strong current at the top and sometimes my angels look like they are skydiving in water!!

I might try the nozzle tomorrow, I would accept reduced velocity, just as long as the flow reaches all areas of the tank

Thanks guys 😀