Can’t figure out micro bubbles source

[JDP]

I have a sunsun 3000HW. Orings and seals are great. No cracks and all fitting are double checked tight. No water leaks at all. I have micro bubbles all over my tank but I physically cannot see any coming from the output. The tank is clean and water parameters perfect but these micro bubbles make it look like it’s cloudy. Anyone have any ideas or experience with this? Have a video but the site only allows photos. 

[Chick-In-Of-TheSea]

I have microbubbles too. They are produced by my HOB. To share videos, drop to YouTube and share the link here.

[TOtrees]

I lack the physics knowledge to fully explain this or even back it up, but I suspect what you're seeing is gasses coming out of solution, due to a change (in this case a reduction) in pressure. I see the same thing when I refill or top up my tanks via the tap, and the various hoses, connectors, valves and shower heads that are connected (not a literal shower head, but a garden shower nozzle that screws onto the hose end). 

I've found the amount of bubbles is greater if I include hot water (ie less likely if only cold water), and if there is anything in the line that is "choking" the flow, or backing up the pressure. Eg if I have all cold water, and it's fully open, with little or no restriction on the flow, I get little or no fine bubbles. So what I think I'm seeing is the effect of water going from high pressure in the lines, to low pressure in the tank, and that change (drop) in pressure causes some of the  gasses that are dissolved at high pressure, to come out of solution, which they do as fine bubbles. Basically the high pressure (or high temp) water can hold more dissolved gas in solution. 

For your sunsun pump, do you have the outflow choked or a valve partly closed, ie to reduce flow? If so, does opening it up reduce the bubbles effect? It's also possible that your pump isn't fully sealed, and is drawing in air (eg around a seal or something). This might be a very small amount, but the agitation in the pump could be breaking any air or bubbles into super-fine small bubbles.