Noisy overflow box - why is one loud and one not?

[Kevomac]

Well, I finally put water in my 215 that I bought used last December, and have almost everything going well. My problem is that one overflow box makes a lot of noise, and the other is quiet. The tank is three feet from the tv in the living room, so this is a nuisance. Here's what I know...

The floor (slab) appears it may be 1/16" off level as more went into one end when I first filled the main tank full enough. The noisy end is the one the water went into first.

The overflow drains on the tank are pvc pipe with caps on the end that have holes for air. The noise appears to be the sound of air gurgling up through that air intake hole.

The water is significantly higher on the noisy side. On the other side, the upper part of the arm (where the "T" comes off the drain pipe and connects into the elbow where the water overflows into the drain pipe) is visible. On the noisy side, it is almost to the top of cap with the air hole.

I plumbed my tank per Melev's directions (the quiet side drains directly to the skimmer section, while the other side drains partially into the refugium, and part of the water is redirected into the skimmer)

Finally, I have a small dripping leak under the tank where I apparently overtightened the bulkehad that carries the water from the drain line into the sump. Could my problem be air from that leak bubbling up into the drain pipe to the top?


Sorry for the info overload. Any suggestions would be appreciated. BTW, the tank has no livestock yet.

[artful-dodger]

I also hope you're still testing and tuning with freshwater rather than the expensive stuff unless you're already curing rock...

I doubt that the leak will pull enough air to make much noise (a pumped/pressurized) line will suck in air. If it did, I'd expect it to be pulled downward with the water (going upstream against 600 gph would be tough. You will want to correct the problem, though, before moving forward...even if it drips into the sump, it will build up stalactites at the point of the leak. The rubber/silicone washer should be on the fixed side of the bulkhead fitting (opposite the nut) usually on the inside of the overflow. If you get it out and find that it is actually damaged (cut, torn) then replace it now. Which leads to another question...did you buy new washers or bulkheads or use the ones from the previous owner? (I'd always replace as a cheap insurance policy. 29 inches of water in an overflow is a lot to have surprising you someday.)

On to the noise...it sounds as if that standpipe isn't able to keep up with the volume since that overflow is getting more (but 1/16" is actually excellent for a six-foot tank!)

I suspect that there might be restrictions in that drain...when you split the line to the refugium and skimmer...did you go to a smaller diameter pipe? Did you use a tee or a wye fitting? If you used a union in the line above the split, I'd try temporarily switching the lower half to a straight shot like the quiet drain.

The sucking air sound, though, in general, usually suggests that the cap holes are not "correct" for the volume being pulled. You can try drilling the holes bigger or just keep adding holes until it doesn't flush anymore. If you overshoot, PVC caps are cheap...buy an extra or use a drop of silicone to plug a hole.

In my experience, the flexible, ribbed spa hose is less noisy than solid PVC, but that may well be because of a larger diameter. (I try to step up as soon as I can after the bulkhead when I do use rigid pipe. (e.g., 1" bulkhead, adapt immediately to 1 1/4")

Just thoughts...I can't claim to be expert, but I've had to debug loud overflows on just about every tank with a sump before getting them tuned in.

[Kevomac]

Very helpful response! I fixed the leak problem today. It appears that the only problem was that the rigid pipe that I was using for drainage was sagging slightly causing the bulkhead to not be totally flat. I'm using plastic "strapping" to support the long drain line, and I just moved the screw that was holding it up a couple of holes further down the strap line. You're right. I didn't add salt to the water until the problem was fixed. I just did that now. As for the noise, I'll try taking the cap off the pvc first and give it unlimited air to see if it fixes the problem. If not, I may have to downsize my pump. I debated a Mag 12 or 18, and went with the 18 because of the tank size. Oh well, if it doesn't work out, I bought the 18 used and can probably resell it for close to what I got it for.

Thanks for the ideas!

[Kevomac]

BTW, I replaced the bulkhead with a new one just to be on the safe side.

[lReef_lKeeper]

how many elbows are restricting the flow through it ?? i have one that has a 45 on it and one with a 90. the one with the 90 is a little louder than the one with the 45. i am thinking that it is the restriction in the pipe.

[Icefire]

Do you have durso?
Are those 2x 1" bulkhead?

[Kevomac]

I have one 90 just below the tank, a "T" with a ball valve below it, and another 90 at the other end above the skimmer section. My initial cut of pipe above the skimmer section was too high, so I jury-rigged a series of two 90s and a some short pipes to lower the pipe to below the water level and lessen noise there. Could that be the problem?

Also, what is durso? My pipes are white pvc and came with the tank when I bought it. The bulkheads are 1", and on the quiet side, it has a 1 1/4" hose barb with a 1 1/4" piece of vinyl hose that goes directly down into the skimmer section.

[Kevomac]

Update...

I tried removing the jury-rigged pipes from the end on the skimmer end to see if reducing the number of elbows would make a difference. Nothing. The water just seems to be higher on one end of the tank than the other. I also tried removing the cap from the drain pipe from the noisy side, and it didn't make a difference either. The water just poured over the top and into open pipe! I'm starting to think I'm down to three options. Replumb the drains with 1 1/4" pipe, which may or may not make a difference, replace my Mag 18 with a 12, or replumb with a return pipe that takes some of the water from the 18 and redirects it back into the sump.

[artful-dodger]

Regarding the Durso standpipe design:

Durso Example
DIY instructions
Pre-built

He also has a page on mods. Plus, there are lots of posts in the RC DIY forum related to standpipe design and silencing.

[Kevomac]

Wow. I'm cooler than I thought. I already had durso pipes on my tank. I have fixed the problem finally. I tried replacing the drain lines below the tank with 1 1/4" pipe, and it didn't make any difference. I then replaced my Mag 18 with a 12. It helped, but not much (I decided to keep the 12 instead of the 18 anyway), and finally took someone else's suggestion of modifying the air intake hole on the top of the pipe. I first bought a replacement cap and started making the hole bigger. Instead, it got worse. So I then bought two more caps, drilled one of them with a smaller hole, and promptly dropped it to the bottom of the 29" deep overflow box! I then drilled the other new one with a smaller hole and voila! Problem fixed!

Thanks for the help!