Ideal Positioning Of Water Inlet

SG 1.002, never really got rid of diatoms, and they do contribute to some unsightly mulm over the sandy substrate.

My lovely Eheim external filter came with a swan-neck water outlet hoze which, given the low level of the water in the tank (see pic), is about 15 cm above the water level, therefore reducing the power of the entering flow. Clearly, plenty of oxygen exchange with this solution.

I'm buying now a U water outlet, so that I can extend the spray bar down to the water level. Now, the entering water flow will be almost vertical, slightly diagonal, to help moving the detritus away from the bottom, and towards the filter inlet. But:

Should I keep the spray bar right below the water surface, thus maximizing the flow power? Or will this kill the horizontal movement of the water, reducing the oxygen exchange at the surface? The alternative would be with the spray bar perhaps 1 cm above water level, so that a minimal surface mixing is at least ensured?

Brackish tank? I would repost this in the Brackish forum section. If it's similar to freshwater requirements then I would position the spray bar to ripple the water's surface. And add a powerhead or two to move the nasties towards the inlet positioned at the opposite end or a corner.

What I've done before is cut the swan neck part to create a U and a 90 degree bend, and insert a length of tubing to lower the sprar bar. I would use the spray bar just below the water's surface pointing just above horizontal to create lots of ripples. Would also consider trying the spray bar along the back wall, so the flow runs down the front of the tank then back up towards the inlet rather than just right>left. Tends to pick up more detritus from the bottom of the tank that way. If you still have issues then invest in a small circulation pump like a koralia.

Thanks folks, i believe brackish makes no difference in these basic things. Plus, 1.002 is so low.end that it can be considered fresh.

The tank is quite long, 120 cm, so I'm afraid the back to front option won't really work.

I was hoping to use the water flow from the filter to both oxygenate and move the detritus away, but maybe I'm asking too much...

you dont need the surface churning to oxygenate the water, as long as it has some ripples its fine.

as mentioned above for decent circulation you want the spray bar on the back glass pointing horizontally to the front glass. You can either get another and join the two together or make your own longer one.

m_attt said:

as mentioned above for decent circulation you want the spray bar on the back glass pointing horizontally to the front glass. You can either get another and join the two together or make your own longer one.

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Interesting, I never thought of something like that, I simply assumed that keeping inlet and outlet at the two extreme ends would guarantee the needed flow. As I understand, rather than having a direct flow between the two, you want to keep the detritus suspended, until it gets caught in the inlet...

Will try that.