Overflow Questions

[Fally]

I am seriously considering putting in an overflow into a sump for my 29Gallon system.

I would like a place to stick my new skimmer where I can kill the bubbles. I would also like to get rid of my canister filter.

I saw a neat looking overflow on eBay and was wondering if anyone had any experience with these or anything like them. I am leaning towards this overflow and don't want to make a stupid purchase.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7740952345&ssPageName=MERC_VIC_ReBay_Pr4_PcY_BIN_Stores_IT

Do you think this will work well?

Thanks!

[dakar]

Pretty much a standard overflow (aka weir box) they are quite reliable when hooked to a small vaccum pump or powerhead to catch any air the develops in the siphon portion. That one rated to 600gph will reasonably handle the flow for your tank, likely you will not want to turn over quite that much water. So it should be fine.

You will need to construct a standpipe or similar ($3 worth of PVC and fittings, very simple to do) to keep the noise level down.

[Fally]

Where would I put the standpipe? On the overflow box?

[dakar]

The standpipe would go inside the back half of the overflow, into the top of the bulkhead fitting.

[Fally]

I see. You don't happen to have a link where someone has done this do you?

It isn't that I am really dense, I'd just like to see how someone else did it. :)

[davejnz]

Here's some pics of the weir/overflow Dakar built for me.I didn't use a bulkhead to plumb the standpipe to.I cheated with some o-ring gaskets and PVC fittings.

[dakar]

I ran into an old overflow box with a standpipe in it earlier this evening, must have been on another tank at some point in time.
I'll see if I can shoot a couple of pics in the morning and post them for you.

[Fally]

Awesome. Thanks guys.

I thought a stand pipe had two 90's on it for some reason. Just having that little length of pipe reduces the noise that much?

[davejnz]

Standpipes serve 2 functions on an overflow.The most important thing is that they keep the water level above the divider in the weir where the water flows down into the bulkhead section.If the water level was left below that mark,the weir/overflow would lose vacuum/siphon.The other thing they do is they can quiet down the noise of the overflow.With small weir/overflows and a high flow rate,they can be a bit noisy.You can make a durso(quiet standpipe)by adding a PVC T fitting that slips on the PVC standpipe with the opposite end of the T capped and drilled for a vent.The opening end of the T fitting you add a elbow fitting(I believe the correct name is called a street elbow)the elbow is fitted so the opening of the elbow is faced down into the water.Water will enter up into the elbow and flow down the T into the standpipe.By drilling the cap at the other end of the T,you allow air to enter thus preventing the gurgling/flushing effect that sometimes happens with overflows.

[davejnz]

BTW,I have 3 of your typical U-tube style overflows as well as the weir that Dakar was nice enough to build me.I'm no longer useing them and if you would like one(they're dirty and used but free),drop me a PM.

[Fally]

Thanks for all your help guys. I ended up getting that weir type from eBay. It is working great. I ended up grabing a part from my LFS to use at a standpipe. I guess it was spare parts from a skimmer. It is a little tube with a sponge on it. The overflow makes no noise at all now.

I will have to snap some shots of everything in operation. I got so much help on this project from folks at CaptiveReefing!

Thanks for the offer davejnz!

[Whoyah]

Depending on the size of sponge you may consider removing it. Overtime it will trap organics which may cause a nitrate problem. If you worried about things getting sucked down the overflow, you could change it out for a bulk head/powerhead screen. I don't have anything over mine but of course I have a few critter take the ride down the overflow pipe too.

[Fally]

It is a really coarse sponge. I noticed today the the overflow wasn't taking from the top of the water. It was submerged and taking water from 1/2 inch under the water. The sponge was gunked up with junk, so I rinsed it out and reset the syphon. it is working fine now. I think the sponge slowed the flow enough to cause that but I'm not 100% sure.

[AquaSquid]

I have the same overflow in my 75. It works great. Get rid of the sponge it clogs, it creates alot of noise and is really unnecessary. I may try the stand pipe idea to cut back on some of the occasional gurgling. You'll be fine with that unit.

[Fally]

I pulled the sponge. It kept clogging and raising the water level in the tank and triggering my float switch. It did reduce the noise down to nothing though. I will have to build a stand pipe for it.

One question AquaSquid. Does your overflow always pull surface water? I have noticed that mine will stop pulling from the surface after a day or so and I have to reset the syphon. Do you have this problem? If not how is yours positioned? Any tips?

[Whoyah]

Once you get the tank level to stabilize, by adding the stand pipe, you should be able to adjust the overflow to only pull surface water. Are you getting air bulbs trapped in the overflow box yet? This will also reduce flow. If that small piece of air tube is used to draw out the bubbles, you can just add a "Water Lifter" to draw out the bubbles constantly. Here is the link for the lifter. I recently added one for my overflow. It works great. I just used some sticky Velcro to hold mine in place.

http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=3642

[Fally]

I have that piece of air line tubing going to a powerhead in the tank. I am pretty sure that there aren't any bubbles in the overflow. It is hard to tell because the acrylic is black.

It is strange, after a day or two the water level looks to be a half inch above the overflow and the box is no longer taking from the top. It is pulling from 1/2 inch under the water and scummy stuff builds up on the surface...

Anything I can do to fix this? It's sorta ****ing me off. My skimmer works so much better when it is pulling the surface water.

[Fally]

This overflow doesn't seem to be pulling enough water through it. Anyone else have this issue? My float valve died and the tank will get pretty close to overflowing. The water level is almost an inch above the top of the overflow box. The pump is only supposed to push 400gph before the 4 feet of head and the overflow should handle 600gph. Am I missing something here? I must not be doing something right. The airline is hooked up to a powerhead,and it starts the syphon fine.

Can anyone tell me what I am doing wrong?

[davejnz]

How tall is the standpipe in the back of the overflow?

[Fally]

There isn't a stand pipe at this point. I had a sponge on there and it was like 3 inches tall at the top of the sponge, but the water level was only 1-2 inches.

I may have figured it out. I had the overflow box adjusted to be level with the waterline. My tank is off by about a 1/2 inch, so the overflow was leaning to the left. I think that air was getting trapped in the right side of the overflow because the airline is on the left side.

I changed it so it was leaning slightly to the right and now the side with the airline is higher. It went overnight without a problem, so I am hoping this has fixed it. The only thing that is bugging me know is how the overflow box is crooked to the waterline... :) I guess when I move I'll have to make sure the tank is level. lol.

I will let you know if this solved the problem long term for anyone who is following this or runs into this in the future.

Thanks!

[Whoyah]

I am glad you got it figured out. I completely understand how frustrating and worrisome it can be trying to keep all of your water levels maintained.

I would recommend a auto-top off for evaporation if you don't already have one. A very handy little machine. I built mine but there are commerical ones available.

I use to have problem with water levels when I did my water changes. Now what I do is empty the auto top off bucket, fill it with the replacement water. I siphon out the water from the main tank and the auto-top dumps in the new water at the same time. I use the same size bucket so I can only remove the right amount a water. Once the water change is done, I rinse the top-off bucket and fill with clean water. This has worked very well for me. I don't have to turn off any of the pumps or valves so I don't need to re-balance the system.

[Fally]

It was killing me because I knew it was supposed to work, but I couldn't figure it out. Finally I got to thinking about positioning and what the screws could do for me. Then I remembered that it wasn't level because the tank wasn't... Duh. Now it seems so simple, but at the time I felt like quite the idiot.

I have been thinking about a top off system. I have to add about 1/2 gallon of water a day... Not too bad.

Sounds like you have a good method for water changes. I will definately keep that in mind. I plan on getting a 75 or a 90 Gallon in the somewhat near future. I will definately have an auto-top-off on that system.

[duckface]

I have the same overflow but mines is the the step above the 600gpm model did yours come with a sheet piece of arylicbecause i have no idea what this is for and it has stopped working. I will try to reprime it i am using the aqualift pump, it works great but still very little if any flow, i am going to try the durso stand pipe see if that helps.

[lReef lKeeper]

send the overflow boxes on up Dave, i can always use extras !!