Best Placement For Diffuser?

[elisew]

I've just replaced my JBL plastic diffuser with one of the tall glass diffusers and after seeing some pics of other tanks I'm a bit mystified as to where the diffusers are better placed, at the bottom of a tank or at the top near the outlet of a filter?

Does placement of a diffuser really matter?

 

[alex.wardle]

i asked a similar question a few weeks back on the planted side and was told as near to the substrate as poss so co2 has the furthest distance to travel before it hits the top of the water and underneath the outlet as well if poss so the co2 infused water is pushed around the tank.

 

[elisew]

i asked a similar question a few weeks back on the planted side and was told as near to the substrate as poss so co2 has the furthest distance to travel before it hits the top of the water and underneath the outlet as well if poss so the co2 infused water is pushed around the tank.

Thanks alex, that makes sense. I'll sort out moving the diffuser closer to the sand in the morning

 

[SuperColey1]

I disagree. The diffuser should be positioned in the best position that the circulation will hold the bubbles in the water longest.

This is one of the benefits of a diffuser against a reactor. You can move it all over the place and just watch where the bubbles are going.

Forget about the time the bubbles take to go up to the surface. You want the bubbles going all over not up.

Sometimes the best positions can be much higher in the direct flow of the filter or circulation pump outlet so that the bubbles get blow over the sides of the diffuser and downward with none going upward:

A few pictures:

So the tank is pretty young, not too much plantmass so good circulation. The diffuser is about a third from the rear and 2 thirds up on the left pane here. the filter outlet is rear right and pushing to the left:

A few months later. plantmass is much much higher. circulation is a huge issue now and the Koralia has been added in the left rear. This diffuser has been moved to opposite the Koralia and the filter outlet is now by the side of the inlet. Therefore the circulation completes a full circle front left rear to right rear, to right front ot left front etc.

You have to position the diffuser where IT works best not settle for time in water. If just holding the bubble in the water longer before it goes straight up is the key then use a ladder. More efficient at this purpose than a disc. The disc advantage is amall bubbles from the start (mist) that are less bouyant than large bubbles which in turn means its easier to keep them in the water for longer, blow them around etc.

AC

 

[jameshughes1989]

SuperColey1 is spot on. Your after co2 distribution rather than longest time before it reaches the surface. I have mine at the bottom still but placed directly underneath a koralia powerhead. This disperses co2 to all of my tank!

James

 

[ian]

i think that was me that made the comment regarding nearer the substrate the better, as we were talking about the JBL diffuser. As the are so big, the closer the better. If no one knows, they are the long cyclinder ladder type. I did also say that they need to be in the flow on the tank or under a powerhead. I have my glass diffuser close to the substrate as i have good flow where it is and the loger the mist of bubbles in the water the better, i also like James have it situated under a powerhead.

It can take ages to find the right position for a diffuser. This is why mist diffusers are best IMO as you can see where the C02 is being distributed.

 

[elisew]

Thanks for the replies

I now have a glass diffuser which has a ladder and the white disc thingy, the bubbles are much smaller now and do seem to float around the tank much better. Since I began using the co2 system I've had the diffuser placed so that the bigger bubble from the plastic diffuser is just under the outlet of the FX5 but the bubbles were gone straight away.

So to clarify, if I place the new diffuser half way up the side of the tank but still keep it under the filter outlet it'll give a better result in the long run?

 

[ian]

place where you feel you get best distribution. Like i said earlier you can see where the bubbles are going and not going, whether it be nearer the substrate or under a powerhead or the opposite side of the tank. It does take some mucking about with.

 

[SuperColey1]

Lol. Flow dynamics

I was putting my pics up to say forget about just banging it near the substrate. Put it where it works best. Like Ian says his works for him low down at substrate level, mine was in 25+ different positions as the plants grew and flow changed.

AC

 

[alex.wardle]

I was nearly right

 

[elisew]

I was nearly right

Bless


I`ve placed the diffuser half way down the side of the tank and can notice a huge difference in the dispersement of the bubbles, should be ok.