Just like the titles states.  I put in a larger return pump I got from Bud.  Looks like a Reeflo Dart.  Not sure on its output though.  I have the plumbing a tad goofy.  I have 2" return coming off of the pump that splits to 2 - 2" Ts.  One the Ts points up and then reduces to 1" before heading into a 10 Gallon tank where I will be putting mandgroves here in a few weeks.  Then the T connects to another T where I am planning to add an ATS if I ever get it built to help with algae growth.  Then the 2nd T reduces to 1" which then heads to my DT where the 1" return breaks to 2 - 1" Returns.

Now I have the 2" Ball Valve that is straight off the pump cranked on Full.  The Ball Valve for the Mandgrove tank and ATS are currently off.  To keep the bubbles from entering the DT I have the DT Ball Valve at right around 1/3 on.  This is killing the flow back into the tank where it has lowered my tank level.  If I give it anymore than that I get the air bubbles shown in the video located here.

I've gone back thru my plumbing and sealed all the joints from the outside with more PVC cement making sure I don't have an air leak. The only other thing I can think of is that there is something wrong with the pump but the pump runs smooth and is quiet to the point you cant even hear it when you sit beside it.

Anyone got any ideas or something I could try to get this stopped?  I am home all day today and home mornings if anyone wants to stop by and take a look at the mess I have.  My cell # is (319) 361 - 8306.

What kind of overflow are you using? Every experience I've had with micro bubbles in the display tank it has been bubbles moving through the sump from the overflow. It can be tricky with a high flow pump like the dart. Overflow water enters the sump with turbulence and the high flow doesn't allow for the bubbles to surface. Even a couple sets of baffles in the sump may not be enough.

Bean animal overflow would be best, u can fiddle with valves and get a near bubble free siphon..if you are using a couple of durso standpipes you may have a struggle on your hands.

Well... I didnt know what I was doing when I plumbed my drain almost 8 months ago so I have 2 1" drains that go to a 2" T and then down a 2" PVC run to the sump. Just a single drain line. So without replumbing my drain, which my finacee will kill me if I need to that, is there any way of fixing my issue? Thought about using some screen like Bud did at the dentist office but I dont see any bubbles in the sump.

Are you getting air somewhere in the return lines? It doesn't seem like your video is linked correctly, so I can't see what you're dealing with. Also instead of restricting the return I would run it wide open and divert excess flow back to your sump with a "T" and valve.

video is a 3gp file taken with my phone. you'll need quick time to watch it.

I resealed all the return joints as well. (forgot to mention that in first post). The returns might be a tad high but they are fully submerged under the water of my DT. I do have a T off spot where I could have water run back to the sump. It is suppose to be my ATS connection. I've ran that spot open half way and the main line to the DT on full and it makes the water bubbles worse.

Keep the suggestions coming. We'll crack the case sooner or later.

new video link - here

can you do a video of the whole plumbing layout. All that one shows is a massive pipe blowing tons of bubbles LOL.

Just curious what size is the intake piping coming from the tank to the input of the pump?

Working on getting the new video tour uploaded as well speak.

From tank to the pump is 2". You'll see the massive ball valve that was used by the previous owner in the video here shortly.

video tour of DT and plumbing - here

I'm going to guess your issue is trying to run multiple 2" pipes feeding from a 2" pipe. Were you running the same setup with your other, smaller pump?

The smaller pump was 1" from the sump to the pump then 1" out to the DT. I broken the 2" return to 1" on this pump as I was told I could easily break off and run other equipment. Starting to wonder if I should've ran 2" return all the way to the tank then to my 1" returns.

maybe just too much pump... bigger is not always better LOL

I was running 1500GPH then that pump crapped out so I went to a 900GPH to get me by for a little bit. Then Bud gave me this one. I have no idea what its output it. Guessing close to 2000GPH. I was looking to get back to 1500 at least if not to 1800 GPH. So is there no way to fix this without replumbing?

I don't know a whole lot about plumbing reef tanks. But that's seems like a hell of a pump for running only a 1" return.

The water may look calm in that sump near the return plumbing without surface bubbles but looking at the rough intake I would be very surprised if they weren't in suspension. You may need to get a light behind the sump so you can see them. If you haven't done that yet please do...

I'm not saying there isn't another issue but I've been in your position before and didn't really see them for weeks after pulling my hair out.

hmmm... not sure what else to do here. Anyone else got something I could try without a massive rebuild?

and if they are in suspension how do I get rid of them?

Discharge cavitation

Discharge cavitation occurs when the pump discharge pressure is extremely high, normally occurring in a pump that is running at less than 10% of its best efficiency point. The high discharge pressure causes the majority of the fluid to circulate inside the pump instead of being allowed to flow out the discharge. As the liquid flows around the impeller, it must pass through the small clearance between the impeller and the pump housing at extremely high velocity. This velocity causes a vacuum to develop at the housing wall (similar to what occurs in a venturi), which turns the liquid into a vapor. A pump that has been operating under these conditions shows premature wear of the impeller vane tips and the pump housing. In addition, due to the high pressure conditions, premature failure of the pump's mechanical seal and bearings can be expected. Under extreme conditions, this can break the impeller shaft.

This might be your issue, Id try opening up every single valve full throttle and see if you can allow enough flow out of the pump to stop the bubbles.

So we're now thinking I have extermely high back pressure that is causing the issue. Never would've guessed the pressure to be that high. Let me see what happens. Hope I dont flood the place lol