Micro Bubbles

[AFishName]

I have had my tank set up for about 2 months now. 1 of which i have had damsels and a couple other small items in. I am having a big problem with micro bubbles! I have siliconed all of my joints on the plumbing to and from the sump. Where else can these be coming from. I can't see them coming out of the return into the tank, but i don't know if that means anything or not. I also noticed a lot of larger bubbles inside the tank side of my overflow. It is a life-reef style overflow with a U tube. I don't know if thats normal or not. What are some trouble areas to check?

Any help would be greatly appreciated!! Thank you in advance! Let me know if you need more information about anything.

[AFishName]

Micro bubbles are harmful to fish right?

[DragonForce]

Micro bubbles are not harmful to tanks. I have the same problem with my HOB prizm skimmer. They just arent very visually pleasing.

I'm guessing your sump doesnt have the proper bubble trap?

[Nøjo]

I thought micro bubbles were harmful to reefs...

[AFishName]

I had heard that the air suffacates fish. But then i've read other places where people add air to there tank.

[tecwzrd]

Originally Posted by AFishName

I had heard that the air suffacates fish. But then i've read other places where people add air to there tank.

I did have a friend who lost some SW fish due to micro bubbles getting stuck in the gills. The kind of bubbles people add to their tank through the use of an air stone or aerator are considerably larger and generally don’t pose any danger although I use these sparingly. It’s better to aim your PH’s at the surface for better agitation and oxygen transfer along with properly venting your cover/lights so excess CO2 doesn’t build up.

Micro-fine gas bubbles sticking to gills could obstruct respiratory gas exchange, by blocking ventilatory water flow between the minute lamellae on the gill filament surfaces, especially on smaller fish.

That said, it requires a decent amount of micro bubbles in the tank to create this problem. If you are only talking about a couple you notice versus the tank looking milky from them then it’s a minor issue imo.

If you are using any additives like Stress Coat etc, this can cause bubbles/foaming. Could be too large of a U tube resulting in low water movement giving bubbles a chance to build up in the top part of the tube. Using a tube just large enough to prevent the overflow box from draining is recommended. This results in a high water velocity through the tube which helps prevent the bubbles from being trapped and resulting in siphon loss.

Turning the pump on and off a couple of times helps sometimes also.

Do you use a pre-filter on the overflow and sump? Do you use a protein skimmer & could it be coming from that? Do you use baffles to control the bubbles? Is your pump submersible or out of the sump?

[AFishName]

Thanks for all your help! The U tube itself isn't getting bubbles stuck in it. It is actually the "bucket" that sits in the tank that the water flows into. These bubbles do not apear to be causing a problem, but i wondered if they could have anything to do with the hundreds of micro bubbles in the tank.

There are foam filters on the overflow and above the bio balls in the sump. The water drops about half an inch from the pipe onto the filter pad then down the bio balls it then goes under a baffle and through another foam filter. It then goes over a baffle, however that baffle is often under water so i'm not sure it does much good. I have a protein skimmer, but have not turned it on yet. My pump is a submersible Mag 9.5.

Thanks again, should i see the bubbles coming out of the return if they are coming from that line? I don't know how else they could be getting introduced...I don't think my top is properly ventalated. Its completely covered except for where the U tube and the return lines are. Could that have anything to do with it??

Thanks

[tecwzrd]

You could raise your pre-filter on the output of your overflow to cut down the splash & bubbles but I suspect it’s the power of your pump and the large flow causing most of your problems. Do you use a 1” return hooked up to the ¾” output of the Mag? Is it all dumping out in one spot? Personally I use a Mag 7 T’d off to go to opposite ends of the tank.

The Mag 9.5 is a 950 gph pump and even traveling 4 feet up it’s kicking out 800 gph. For a 45 gal tank that’s a 17 times turn over on the sump pump alone not to mention any PH’s you might use. While turning your tank over that many times is desirable it could just be more than the overflow/tank can handle without causing bubbles since most overflows are designed to handle 800 gph max.

Have you tried a slower pump like the Mag 7 or 5? Do you use a ball valve on the return and have you tried limiting the output?

If you don’t see the bubbles in your sump or coming directly from the return it could also be the return is too close to the surface causing an unwanted venturi effect.

The top not being properly vented shouldn’t cause the micro bubble issues but can lead to other hazards like quick drops in PH and the fish not getting enough oxygen. If you have at least a couple of inches free in the back due to your overflow and return and have good surface agitation then it shouldn’t be an issue. It’s more of an issue on deep tanks like some of the high hex tanks you see in your lfs.

Besides breaking it all down and double checking for any pin hole leaks I’m running out of ideas.

[AFishName]

I have a 3/4" return pipe coming off of the mag 9.5. It then makes a series of 90 turns and runs about 6-8' up and over to the tank. Would this cause to much pressure? I do have a ball valve on it and it is throttled back a little becuase the overflow is only rated for...i believe 700gph (not sure) and it couldn't keep up. Do you think it would be a good idea to go ahead an slow it down a little more? could that be causing this?

As far as the top issue, i have the whole tank covered except for the return and the U tube (i cut around them) the sump is not covered yet, but i was going to build a cover for it. I have been having problems with the ph dropping...maybe thats why? The tank is set inthe wall under my stair case so i wanted to keep it covered so dust will stay out of it. oh and should i put a PH towards the surface of the water to agitate it? Would this cause more bubbles?

Thanks again,

[tecwzrd]

Originally Posted by AFishName

the overflow is only rated for...i believe 700gph (not sure) and it couldn't keep up.

If the overflow has a 1” intake then it’s closer to 600 gph. A dual 1” intake can handle up to 1200 gph but it has to be fairly wide.

Although the return on the Mag 9.5 is ¾” I would step it up to 1” for better handling the flow & also T it off to return to both sides of tank and not just one drop off point which will also aid in circulation and aeration of the tank. Most micro bubbles are created in pressurized situations.

Decreasing the output could help and it shouldn’t put too much back pressure on the Mag but a better option if you want to keep the high turnover rate would be to install another overflow. Just make sure your tank is level & make sure the overflows drains are not underwater. Undersized overflows are a common problem. Few can ever handle larger sized pumps.

You could also utilize a 25 micron bag to help stop the bubbles on the pre-filter if you clean it several times weekly. If you neglect to clean it though, the micron bag will become biological and help to produce nitrates. These bags that fit over & on the end of your down pipe run around $4. Probably more work than it’s worth though.

Unless you have an eel or fish that jump having the tank completely covered so tightly can lead to PH drops sometimes along with limiting oxygen transfer. Especially if your tank is higher than longer. With an overflow and sump dust should not be an issue at all. Tanks without an overflow can sometimes get an organic/dusty grit floating at the top but the overflow would remove any dust that accumulates. Also you should have the top water briskly undulating but not to the point that it creates excessive splash to keep down on salt spray. Using a PH to do this is fine but the return from your sump pump should be able to handle the task alone and you can use the PH’s to create lower turbulence.

Wetwebmedia has some great FAQ’s on these issues as well.
http://www.wetwebmedia.com/bubtroubfaqs.htm
http://www.wetwebmedia.com/pbfaqsmar.htm