Micro bubble help, please?

[FishWife]

We did some open-heart surgery on our system the other day, and switched out our mag 24 for a Sequence Dart. We added an upper manifold, too, with four outlets, 2 on each side of the tank. Simple vertical, 3/4" pvc construction with two 1/2" outlets each: 4" and 8" from the surface. Nothing fancy. So, there's a T coming out of the Dart: one serves our 8-outlet manifold (that the mag used to serve)...

 

and the other serves these two "upper manifold" returns. We also added another siphon return to our sump (which we call our super sucker) so that the Dart can deliver flow and not overwhelm our overflow box, which maxes out with two bulkheads: 1" and 3/4".

 

It's SO much quieter, and the tank is running cooler! Hooray!

 

But, now we have micro bubble problems, especially coming from our upper manifold. :(

 

Reasons we think we might have this problem:

 

1. Our sump/fuge/bubbletrap is running really fast with the increased flow through the Dart.

 

2. Our Dart required a check valve, which is black rubber: are our clamps not tight enough? (We have temporarily got stainless steel ones on there; will change to plastic asap... where do we get some?)

 

3. Our Dart now pulls from our last overflow division in our sump, which, again, is receiving more flow and it seems like our bubble trap isn't trapping enough bubbles because of the flow. (Same as #1) We wonder, though, is it that we don't have sponges over our three-way grated 2" drainpipe that then feeds the check valve? Like, would sponges/socks/filter bags help with bubbles?

 

What do you all think? TIA!

Edited October 25, 2007 by FishWife

[flowerseller]

You have mentioned many valid possibilities.

Sometimes they stop producing mb's after they've run for afew hours to a day.

You could have a small leak that draws air in on an intake or in your manifold.

[jason the filter freak]

I'm thinking it is the last one most likely, this is quickly becoming more and more similar to Christinas tank but on a higher scale. I like it

[FishWife]

I like it.

 

Thanks, Jason! You were such a great help!

 

PS I have NOT forgotten your pictures. Just hard to get time, camera, and upload all in the same place, 'specially since my 'puter rejected my camera's software, so they have to go via Scott's to my thumb, then time/opportunity to upload (when I can find a cable, since *my* computer's wireless is gone) to the 'net, then post. Sigh.

 

Sometimes, like Bertie Wooster said of the oysters upon learning that a grain of sand causes the irritated molusk to coat it with pearl essence, "Sometimes it seems like the life of an oyster is one bally thing after another."

 

You have mentioned many valid possibilities.

Sometimes they stop producing mb's after they've run for afew hours to a day.

You could have a small leak that draws air in on an intake or in your manifold.

 

Chip: leaks (don't SEE any) get plugged eventually with salt, right???

 

Where do we get plastic clamps to supplant metal ones, please? Are they just plastic rip ties?

 

If the problem is that our flow is too fast... what to do?

1. Socks/filter bags on 2" intake pipes: do they help or hurt?

 

2. Filter material below the surface level of the last overflow baffle to retard bubbles from dropping down to where the pump sucks them in?

 

Hmmmm. Ideas?

Edited October 25, 2007 by FishWife

[Rascal]

First, your questions. You can dial down the flow with a valve on the outlet side of the pump. Nothing wrong with using metal hose clamps on the outside of the tank.

 

Next, a couple of comments:

 

Personally I think the Dart is too much pump for a return on that size tank, especially with the small overflow drains. Even with the "super sucker" (nice idea, btw), 3000 gph is an awful lot of flow to be running through your sump.

 

More importantly are you absolutely sure that you want to trust your entire reef to one black rubber check valve? A little bit of something (snail, sponge, you name it) gets in there and prevents it from sealing properly when the power goes out and you will end up with a lot of water on the floor and a lot of dead stuff in the tank if you don't catch it quickly enough.

 

Why not put the Dart on a closed loop, with true union ball valves on each side of the pump, and then plumb your return with a smaller pump (Mag 7 - 9)? JMHO.

[Brian Ward]

Thanks, Jason! You were such a great help!

 

PS I have NOT forgotten your pictures. Just hard to get time, camera, and upload all in the same place, 'specially since my 'puter rejected my camera's software, so they have to go via Scott's to my thumb, then time/opportunity to upload (when I can find a cable, since *my* computer's wireless is gone) to the 'net, then post. Sigh.

 

Sometimes, like Bertie Wooster said of the oysters upon learning that a grain of sand causes the irritated molusk to coat it with pearl essence, "Sometimes it seems like the life of an oyster is one bally thing after another."

Chip: leaks (don't SEE any) get plugged eventually with salt, right???

 

Where do we get plastic clamps to supplant metal ones, please? Are they just plastic rip ties?

 

If the problem is that our flow is too fast... what to do?

1. Socks/filter bags on 2" intake pipes: do they help or hurt?

 

2. Filter material below the surface level of the last overflow baffle to retard bubbles from dropping down to where the pump sucks them in?

 

Hmmmm. Ideas?

 

Where do we get plastic clamps to supplant metal ones, please? Are they just plastic rip ties?

As long as the clamps aren't submerged don't worry about going plastic. You chose stainless so that will even withstand the salty air for quite a while.

 

If the problem is that our flow is too fast... what to do?

1. Socks/filter bags on 2" intake pipes: do they help or hurt?

 

Don't block your intake with anything, you can put filter bags on the drain side going into the sump but I don't think that's going to solve a whole lot. You definitely need to dial back the dart to slow the flow through your sump - running the water through there so fast isn't doing any good anyway. this is actually why the closed loop and the filtration loops are typically run by separate pumps - you want flow through the sump at 5x to 10x per hour, the closed loop supplements that providing flow as high as 50x per hour for demanding sps (though that seems like overkill to me). You may want to look at providing multiple inputs to the dart - one for the closed loop, the other for filtration? I'm not sure if that'll work but it's something to think about. a good idea that I'm definitely going to do on my sump this weekend is to put an elbow facing down on the inside of your bulkhead to draw the water from the very bottom of the sump.

 

2. Filter material below the surface level of the last overflow baffle to retard bubbles from dropping down to where the pump sucks them in?

If you put filter material near the intake for the pump it's probably only a matter of time before the pump sucks it in. I wouldn't recommend it. I think your best bet is to dial back the flow and see if that fixes the problem. if it doesn't and you're not seeing any micro bubbles in the sump then you probably have an air leak somewhere else.

 

Also - don't trust a check valve, it will eventually fail. It sounds like your siphon return is a disaster waiting to happen. Look into supplementing with additional hang-on overflows - you need a siphon break based on physics rather than mechanics.

[flowerseller]

I believe there as as many failures from siphon breaks than a back flow valve.

 

A failure with a back flow will likely lead to a slow leak back but also can depend on the type of valve used and the owners maintanance habits.

A failure to a siphon break can lead to a much faster flow back if it's blocked and also depends on the owner.

 

Am I wrong that all the piping is part of a CL or is it hooked directly to the return?

A dart throttled back as a return can be fine for that tank and could also be used for feeding other equipment.

[Rascal]

From the description (black rubber with hose clamps) it sounds like they are using one of the check valves designed for a sump pump. No personal knowledge here, but I would guess the more expensive PVC ones are more reliable.

 

It looks like everything is hooked up to the return, not a closed loop. I personally wouldn't trust either a siphon break or a check valve with all of the returns on the bottom of the tank. Even a slow leak could be enough to drain the tank if the return pump lost power during the middle of the day while the tank was unattended for a few hours.

 

However, in re-reading that post I noticed that since the picture was taken they have added two returns on each side 4" & 8" from the top of the tank. In that case the plan makes more sense to me. Even if the check valve fails the most that will drain is the top 4". A messy situation to be sure, but most of the reef would still be submerged.

 

As for the pump -- I agree w/ what's been said about not restricting the intake. Dial back the outlet if you still want to use this pump as a return -- but that also poses problems. If you dial it back to 1000-1200 gph, that will be divided between 12 x 1/2" outlets of only 80 - 100 gph each. If you want very dispersed gentle flow, this could be perfect for you, but I don't think it will be enough to get currents bouncing off things and creating turbulent flow. Opening the Dart up and letting it run unrestricted at 3000+ gph probably provides great flow in the tank with those manifolds but it seems to be too much for your sump to handle.

 

Which brings me back to the idea of converting the Dart to a CL pump using the bottom manifold and then getting a smaller pump (or even another dart, dialed back to the desired rate) as your return going through just the upper manifolds. You could even use the "super sucker" as the CL intake -- you'd just have to add a T to prime it (for ex. see here: http://www.melevsreef.com/closedloop.html). Also, if you place these upper returns so they just break the surface of the water by an inch or two and angle them slightly downward, it will create nice turbulent flow by colliding with the currents from the bottom manifolds AND take care of any flooding concerns caused by back-syphoning when the return pump goes off.

 

HTH. Best of luck whatever you decide.

Edited October 25, 2007 by Rascal