Micro bubbles issues

[DaveG99]

I have a quit one 5000 (1330gph)in my sump going up to the 2 outlets on my aga rr 125 gallon tank. There are zero bubbles where the water gets collected to be sent back up to the tank. I have a piece of soft hose going from the QO 5000 connected to a "T" that goes about 2ft both to the left and the right through PVC pipe and then it has one PVC 90 degree piece on either side that go up to the return nozzles. Could 90 degree pieces cause micro bubbles? It really isnt that bad but they are visable. If I get rid of the 90's and replace them with 45's should it help?

[reefD]

no aslong as the break is above the outlet of the tank it shouldnt matter. first clear all air pockets from the return line. next consider aggitation as an issue. if return line is submerged wher water come out it maybe creating a pressure zone in the pump. this causes aggitation. very bad for the impellor. does the pump sound like its working hard? just consider aggitation. best way to explain it is how a submerine creates bubble from its impellor even in deep waters. this is a possible danger for a sub and is how lots are picked up by sonar ...etc. just and example and something to consider. how new is this loop?

[reefD]

is flow high? reducing pumps flow rate may stop aggitation.

[DaveG99]

The only thing i think it may be is this. I used to have an external pump hooked up to this and the black line that goes from the pump to the "T" in the PVC line is long. I need to cut it and make it shorter. Let me take another pic and post it here to help. The PVC pipe you see has two barb ends that are connected to more of that black line and they connect to the returns in the tank on either end of the tank. So the return line is submerged in the middle section of the sump. Would this cause the agitation that you are talking about?

http://i36.photobucket.com/albums/e44/daveg99/67c8c554.jpg

[reefD]

yeah that would decrease pressure. start with that.

[reefD]

on further inspection that line should be free of submersion once it is removed from water near pump. in other word where it comes out of the water from the pump should be the last place it is submerged. this will help you see any open pinholes or reduce pressure variations throughout the line. just an idea.

[AZDesertRat]

The first thing that jumps out at me is the plumbing attached to the suction side of the pump. What is it and why is it there? You never want to restrict the suction side of a pump. If you must have something to prevent vortexing then use a 1x1.5 or 2" bushing and make it larger than the suction, like 1.5" or 2" elbows. That way it doesn't restrict the flow in any way.

[reefD]

AZ if your speaking about that black vacume looking tubing i agree it just makes me wonder...with concerns.

[AZDesertRat]

No I am looking at the 90 degree elbow screwed on the suction side. The flex tubing is probably not a good idea either if it is ribbed inside as it will cause a tremendous amount of head loss. Better off to use clear heavy reinforced tubing.

[reefD]

ohh yeah! didnt even think of that obstruction.

[DaveG99]

I have a sponge on the suction side of the pump. It came with my old mag pump. And I use that pond tubing because that clear stuff is soooo hard to bend. And there are no 90 degree elbows in that picture.

[77]

i have the same problem.
pump is not sucking any air bubbles at all and where the return goes into the tank it is about 1 inch under the water. i don't see how i am getting micro bubbles and doubt the pressure on the return would affect the pump. i have tried tapping the pump off to only allow a little flow back to the tank and it seems the same.
i have resorted to using a filter sponge where the water comes back into the tank but still some bubbles are getting through.
this is the same set up as my last tank and i didn't have any microbubbles in it.....
where do the bubbles come from? if there is no air in the return, do the 90 degree bends cause it? cause thats the only thing i can think of.

[reefD]

the reduced flow from a 90 bend causes the pump to have more over head pressure thus work harder. this can create aggitation which will create bubbles in the pump. now this isnt every case but this is why any over head obstruction can increase pressure and liklihood to cause cavitation and bubbles.

[DaveG99]

when I had my 50 gallon set up I had a rio 1700 pumping the water back into the tank and it had zero micro bubbles but there were no 90's in the piping. I am going to try and put 45's in there instead of 90's and see what happens.

[reefD]

<a href=showthread.php?s=&postid=7374980#post7374980 target=_blank>Originally posted</a> by 77
i have the same problem.
pump is not sucking any air bubbles at all and where the return goes into the tank it is about 1 inch under the water. i don't see how i am getting micro bubbles and doubt the pressure on the return would affect the pump. the pressure causes cavitation which seperates the oxygen in the water from the water thus air pockets and bubbles.

[reefD]

good plan to at least rule out the issue being the elbow.

[jester805]

I have a similar setup and am also fighting with microbubbles. I recently put a piece of foam pre-filter in front of the intake on the pump. It slows down the output, but also helps with the bubbles. Are you guys saying that there should be nothing blocking in intake on the pump at all??

reefD, I don't really understand what you are saying about different parts of the return line being out of water? Why would that make a difference?

[DaveG99]

Youd think micro bubbles would go up wards since they are air in water. But they seam to just go around the tank and not rise at all. Weird stuff. Mine really arent that bad but I am just being anal about my new tank.

[jester805]

<a href=showthread.php?s=&postid=7377703#post7377703 target=_blank>Originally posted</a> by DaveG99
Youd think micro bubbles would go up wards since they are air in water. But they seam to just go around the tank and not rise at all. Weird stuff. Mine really arent that bad but I am just being anal about my new tank.

That's exactly what my tank is doing too.

[DaveG99]

If I could kill micro bubbles I would.

Micro bubbles = The Devil