Overflow flushing

[DMBillies]

I'm still trying to get the 92 corner bow that I bought before Christmas up and running. I had to make a sump which ended up being more time consuming than I thought. I got all of the plumbing in and running last night. Of course, now I see a small flaw in my sump design, so I'll have to take it back out and make some adjustments. Microbubbles are making it through a chamber that I thought would settle them out, so I need to put in a baffle to slow down the cross-flow pattern that's going on. Pain in the neck to get everything back out from under the tank, but an easy enough fix (I think ).

Anyway, my other problem is that the overflow is flushing. The water level will move up about an inch inside of the overflow and then the water level will suddenly drop. When the water level gets as low as it goes the durso sucks air in through the water intake and makes an awful gurgling sound. I thought the air hole on top of the durso might be stopped up, but it looks clear and seems to be sucking some air in fine. I tried putting a hose on the airhole and blowing air into the durso. This stops the flushing, but causes a really loud bubbling sound. Also, I obviously can't stand there and blow into a hose forever. I just wanted to see if maybe it wasn't getting enough air. Is it possible to overwhelm the durso with too much water even though the water level seems normal inside of the tank (i.e., the pump isn't pushing so much water that it is pushing up real high in the tank)? I've never had a problem with flushing in this kind of situation and I can't really figure out what the problem is. I thought about throttling back the pump a little, but the pump makes an awful sound when I do it and it seems like it doesn't help with the flushing unless I cut it back to almost nothing. Just collecting thoughts. Thanks for any input.

Tank info: 92 gallon AGA corner bow with a stock overflow, standard 3/4" return from the pump, and 1" bulkhead with a durso standpipe to take water back to the sump. My return pump is a Quiet One 4000 (probably bigger than I need, but it came with the tank and seems like a very nice pump). My sump is a 20 gallon tall (it's the only thing I could find that would fit ).

 

[Ebmorri]

This is from www.dursostandpipes.com

"The hole on the top of the standpipe (in the End-Cap) is very important. Without the hole, a full siphon will be created and water will be sucked out of the overflow chamber to fast. The water level will drop below the intake and you will get a terrible air sucking noise. If you drill a hole and the water level still drops to far (making a sucking noise) then the hole is to small. Just make it slightly larger (see above) and the water level will raise. If you make the hole to large then the water level will be to high. (It should not overflow the tank as it will not get that high, but keep an eye on it). If the water level is to high this can be fixed easily. Seal the hole with aquarium safe silicone and use a toothpick to make a small hole in the silicone. If this turns out to be to small, remove some silicone with a smaller drill-bit or some other tiny sharp object. No silicone handy? You can try some old well chewed bubble gum to reduce the air hole size for testing If you really mess up, then get a new End-Cap (they are cheap)."

 

[fishdoc11]

Just make the hole a little larger at a time until the flushing stops.....should be an easy fix

Chris

 

[crumbletop]

Yeah, the hole isn't letting in enough air. On another note, since you are having trouble with bubbles, you could always try for a smaller pump than the QO 4000. The easiest thing right now would be to just enlarge the hole in the durso, though.

 

[turboex901]

hey brian, if yo wanna let the qiet one go for whatever reason lemme know. im lookin to bump it up a little bit. im using a mag 5 right now which is awesome for dwell time for the skimmer and refugium but i want to up it jst a tad. <~~~steve

p.s- just so i dont derail youre thread i had the EXACT same problem on my 92 corner, i kept enlarging the hole until it stopped. literally it was prob 1/4" hole!

 

[DMBillies]

I started drilling a hole and the second hole I have now is easily bigger than the original hole. I thought by the time I got to that point that the problem would be solved, so I got nervous about it and decided to stop making it bigger. It's definitely flushing slower than it was, but is definitely still doing it. I guess I can continue with it...

Steve- If I decide to sell it, I'll let you know. If I can get the flushing to stop and if I can get the bubble issue under control (I would be optimistic, but I've had enough experience with this hobby to know better), I'd actually like to keep a higher flow pump.

 

[jacksparrow7]

I am running into the same problem here. I was wondering the outcome of yours? thxs

 

[DMBillies]

Well, I opened up another hole in the top of the durso that's about 1/4", so that's two 1/4" holes in addition to the hole that comes with the durso. It seems to have solved the flushing issue, but now it sounds like Niagara Falls in my kitchen. So, I think the real issues is just that I'm trying to push too much water through a single overflow. This is weird to me because my 90 has a smaller bulkhead and a pump that only pushes like 90gph less...I've never had a problem. In any case, because I was forced to use a 20H for a sump it seems like I don't need all of that flow. So, I haven't decided for sure, but I think I might have to downgrade the pump.

 

[fishdoc11]

Do you have it hard plumbed to the sump? That will make more noise than the flex that came with the 90. Also overflows will quiet a little with time due to buildup of "slimy stuff" in the pipes.

hth, Chris

 

[crumbletop]

You could potentially add some height to the durso. The waterfall could be simply because of the distance down. It is also possible that it is due to the force of water because the flow rate is too high for the overflow. IME, if the water completely covers the slits in my AGA, that signals too much flow. If you still have some air space at the top of the slits, then making the durso taller could help with the waterfall noise.

If the noise isn't from the overflow but in the sump, that is another story.

 

[DMBillies]

Chris- I have it plumbed with flexible tubing, but because it is 1 1/4" tubing, it's not very flexible and it is almost a straight drop into the sump because of how the sump needs to fit under.

Jack- The water is not covering the slits (good 1/4" from the top). I'm not sure I follow you on making the durso taller... I have it pulled all the way up so that the water that comes into the overflow only "falls" about a 1/2" to the level of the water in the overflow. I've tried to make it lower, which seems to help the noise coming from the durso, but causes the water flowing into the overflow to splash. I'll talk to you about it at the swap tomorrow.

In any case, I don't think it's actually the water hitting the sump that is creating the noise... of course, I could be wrong. If it was that, is there anything creative I can do to slow down the flow before it gets to the sump.

 

[phudeb]

Brian, what length do you need? i'm not saying it will fix it but will help as Chris mentioned. I think you are pushing a tad too much thru there. I had the same overflow kit and was pushing ~800 max.
I'll bring some flex tubing for you tomorrow.

phu

 

[DMBillies]

Phu, it can't be more than three feet.... but to clarify what I was trying to say, I already have the flexible braided PVC. It is slightly flexible, but because it is a short length and a thick tube, it has very little give. Do you have something different?

I'd appreciate any help I can get. If I combine enough "fixes" I imagine I can get the thing going without replacing the pump... I just hate the idea of going to a smaller pump because I feel like I'll eventually need the bigger one

 

[pitbullpooch]

<a href=showthread.php?s=&postid=9026723#post9026723 target=_blank>Originally posted</a> by DMBillies


I just hate the idea of going to a smaller pump because I feel like I'll eventually need the bigger one

really all you want is about 4 or 5x your tank volume going through your sump(not saying you didnt know this already) so you want 460 gph at most going through your sump so you would actually be better off downsizing and then just use the q1 4000 for a closed loop and replace it with a smaller pump for your sump return. just an option to look into

 

[bbehring]

Brian, I have a 54 corner bowfront RR AGA. I too had the same issues with my overflow flushing. Take a look at my photos here: http://s136.photobucket.com/albums/q169/bbehring/

I solved with a series of things. 1. Drilling the larger hole in the top of the durso which most have suggested here. 2. I placed a about a 3 foot long piece of airline tubing in the hole. At the base of my bulkhead overflow into the sump I installed a gate valve, which allowed me to ever so slightly to adjust the flow, which completely sliminated the flushing and bubbles. 3. I teed off from the overflow before it made it into the tank and ran a separate vertical 3/4" pvc air line up with a cap w/ small hole in cap. All this combined completely quieted the flushing and all the bubbles. All the piping behind the tank has now been painted black with black fusion spray paint. Looks fab. Don't have photos up of the painting yet. Hope this helps

 

[jacksparrow7]

WOW, that is awesome Brent. I don't no if I have the skill to do that but I was told to shorten my drain lines because the loops and dips cause the back up of air and thats where the flushing comes from.
Brian, I have reduced the size of my drain hoses, I tried to use that flexible pcv piping but the restraints under my corder 90 is to short of a distance and the pvc is very ridged in this short space. I had to use the drain pipes that came with the tank, look like a vacume hose,and cut and spliced these togeter, I hope this works. I also was able to remove the cap to my durso pipes and the flushing sound still remained. The water level in my overflow is just 2 inches below display level. I am using a mag 12 for my pump. The water level comes above my elbow on the durso, is this bad? My tank height is close to 30" and my durso is 28". I think this is right, I am worried because watching the water level rise and fall in the overflow sometimes comes close to the top of the durso. I know the water level in the overflow should remain constant but mine moves about 1" to 1 1/2". Any idea's?
Sorry for being long winded but being new and having my tank apart all over the living room is starting to get on my wifes nerves and I am out of ideas, local LFS is really no help without costing big $. Thanks for the help. Jack

 

[bbehring]

jacksparrow, really not much skill in what I did. I would start with raising the durso up slightly, almost to the underside of the frame. Then, drill a slightly larger hole in the durso. Just use a towel to cover the surrounding tank to keep the pvc splinters contained. If this hole size does not work, you can drill the hole slightly larger until it does work. I think this will equalize the volume inside the overflow area and stop the fluxuations. In concert if you are able, get a gate valve installe just out of the overflow, between where the bulkhead is and the top of the sump. This allows just a slight adjustment to the flow to equalize and stop the flushing/splashing and bubbles. Also don't forget to silicon (or glue and use threaded fittings with teflon tape) the standpipes into the base fittings or when the power is off the water will slowly leak back into your sump and could cause an overflow situation.

 

[bbehring]

Brian & jacksparrow might check out this link if you haven't already... Herbie overflow. A bit lengthly but worth the read.

http://reefcentral.com/forums/showt...threadid=344892

 

[jacksparrow7]

I was wondering if I could use a 1" pipe for the durso instead of the 1 1/4"? Thanks Jack

 

[APFish]

I am running about twenty times the volume through my returns into the sump, BB. What I have done to quit down the Niagra Falls effect is putting tops on my sump. I drilled holes through them to allow the flexi-tube down and into the sump. Hope this helps and good luck.

Rob