Well I've been getting cloudy looking water and apon closer inspection I believe its micro bubbles. I'm running a Fluval 405. Bottom tray has pre filter, second tray up has carbon (came with filter, still trying to decide what to put there) and top 2 trays have Biomax.. What causes this? It does look like its coming from the filter.

Thanks
Roger

Your filter has air in it! Prime the filter or try tipping it back and forth to let the air out! If that doesn't work, check to make sure all your connections are tight and there aren't any holes in your tubing!

Hope this helps!

I'm not sure if my advice will be correct but i'll have a pop (someone else will definitely know).
If it is very small bubbles take out the pre-filter and replace with floss, also remove the carbon, you only really need this to remove nasties or any meds you might have used, then replace the carbon with another tray of bio-max, remember to add some filter start.
I think the floss should reduce the small bubbles.
Did you buy the filter recently ? It takes a while for air bubbles to work their way through the filter.
The bubbles should disappear in time.

Thanks for the quick replys. I will try all the suggestions and let you know what works. The filter has been running for about 1 1/2 months now. Maybe some air trapped in it.

Thanks again
Roger

Make sure the exit tubing isn't clogged.
The turbulence of the rotor could start "making" bubbles, that keep getting trapped in the motor.
But just air left in the housing is the most likely option.

sometimes, the discharge point is a contributing factor. if it is higher,
there would be rippling effect and the bubbles. sometime, there is an air
inlet that causes the tiny bubbles. either way, it will not harm your fish.
it will help you oxygenate the tank

I don't think the bubbles will make the water cloudy. Check for ammonia or nitrites. have you got enough Bio in the filter?

Do you mean you have 1 lot of bio media in 1 tray? if so I would add more asap. if the bubbles are from the filter most likely you have air inside. re prime. check all air is out of hose and make sure filter is on level ground.

CHECK Ammonia-Nitrites 1st. get that filter more media 2nd.

This may be an obvious one but ensure that you don't have your airstone/s near your inlet. This will cause the filter flow to be non-consistent, possibly damaging the filter and perhaps causing the 'micro' bubbles.

Is the outlet above the water level and as the returned water hits the surface and taking water with it. I sometimes get little bubbles in my tank when refilling after a water change if i dont put the hosepipe down in the tank far enough (these bubbles dont last long tho)

Any chance of a pic

Ok problem solved. It was just air in the filter. This is my first canister filter so I'm still getting used to it. As for the media, the top 2 trays have Biomax so that is two trays or four compartments. My water readings are perfect amonia 0, nitrite 0, nitrate 20 (just before wc) and PH 7.6. Thanks all for the support.

Roger