Need help with my sump

[Sassafras]

If I am reading it correctly, the OP is essentially having two problems...

1. "I'll have my sump perfectly balanced (drain/pumps) then randomly my display tank starts to overflow." and...
2. "If I have drain fully open the pumps aren't strong enough to overcome water draining to sump"

I understand the first one, the drain is partially valved off and the flow from the pumps increases slightly over time causing the water level in the display tank to slowly rise and eventually overflow. I'm not sure about the second issue. If the drain is fully open and able to carry all the water, which it evidently is since the pumps "aren't strong enough to overcome water draining to sump", the flow should be completely determined by the volume that the pumps are pushing. There could be a surge of water to the sump immediately after the drain valve is opened, as the overflow tower empties, but once that is down to the level of the drain, the flow to the sump and flow to the tank should be equal.

I agree with Backfromthedead , If you run a full siphon drain, You've got to have a back-up/emergency drain. What about it V Vinylmation , are we on the right track regarding what you are trying to achieve with your overflow?

 

[Sassafras]

Didn't think about this earlier, but noticed in your 2nd photo that you have back flow preventers ahead of your pumps. Does water flow into the overflow tower only from the aquarium water surface as we see in your 5th photo, or does it have other inlets, such as from partially submerged outlets or even slots lower down on the tower walls? I ask because just as you can never depend on a pump to always pump the same volume or a pipe to always discharge the same volume, backflow preventers will also all eventually fail.

 

[Backfromthedead]

In my mind, the 2" drain is acting like an open drain right now with either not enough flow, or not restricted enough at the valve, to achieve the full siphon. When it attempts to complete the siphon, the water in the overflow is quickly sucked out and its right back at square one as an open drain. 2" drain will carry a lot of water, i just dont think the OP has the drain valve closed off enough to make this a full siphon drain.

Tbh i dont see how this rig can run "safely" in the current configuration. Sassafras is right in that a pump can fail up as well as down, lose control over its flow and overwhelm the drain. Without the emergency drain its not worth the flood risk to me, but maybe a fine tank for the garage or basement with a drain. Or break it down and drill a few more holes.

I personally dont use the backflow preventers in every setup but i always make sure to have enough sump space to catch all backflow from the return lines.

 

[cockroach]

My tank has 1 2" drain and 2 3/4" return lines. The pumps are running 1" PVC from the pumps to the bottom of aquarium then reduced to 3/4". The aquarium is drilled on the bottom. Full syphon on the bottom of the aquarium, all I have is a strainer, I have no durso, herbie, bean animal etc. I purchased this used so I had no say in the sizing and number of holes on the bottom of the aquarium. I had the aquarium balanced at 70% power so now I'm experimenting and having the tank balanced at 100% power. To balance the drainage, I have a gate valve.

Can't see clearly, but if your drain is on the base of aquarium, you need a stand pipe cut to the height you want the water to be. Then it acts as an overflow. A syphon will keep your floors wet and wife angry indefinitely.

 

[Vinylmation]

If I am reading it correctly, the OP is essentially having two problems...

1. "I'll have my sump perfectly balanced (drain/pumps) then randomly my display tank starts to overflow." and...
2. "If I have drain fully open the pumps aren't strong enough to overcome water draining to sump"

I understand the first one, the drain is partially valved off and the flow from the pumps increases slightly over time causing the water level in the display tank to slowly rise and eventually overflow. I'm not sure about the second issue. If the drain is fully open and able to carry all the water, which it evidently is since the pumps "aren't strong enough to overcome water draining to sump", the flow should be completely determined by the volume that the pumps are pushing. There could be a surge of water to the sump immediately after the drain valve is opened, as the overflow tower empties, but once that is down to the level of the drain, the flow to the sump and flow to the tank should be equal.

I agree with Backfromthedead , If you run a full siphon drain, You've got to have a back-up/emergency drain. What about it V Vinylmation , are we on the right track regarding what you are trying to achieve with your overflow?

1. is correct
2. not really an issue.

My drain is sitting on the bottom of the aquarium. I never have any issues maintaining a syphon. I also never have any air coming into the drain. I know having multiple drains is the ideal setup but I'm not going to break down the tank, remove everything and drill a 2nd drain. An option is adding a PVC riser and creating a dorso drain system. If one pump fails or if the pumps power reduces over time, I'm not to worried about that. My sump can catch all water in the event of a power failure. It would only lead to water splashing from the returns which is fine. My issue is overflowing the main tank. My theory is if I can balance at 100% power, the pumps cant spit any additional water. This setup is not ideal but I'll have to manage for the time being. The goal is to upgrade to a larger aquarium hopefully at 96x36x30H" from custom aquariums. This one will be built correctly.

 

[duanes]

Can't see clearly, but if your drain is on the base of aquarium, you need a stand pipe cut to the height you want the water to be. Then it acts as an overflow. A syphon will keep your floors wet and wife angry indefinitely.

Agree with this.
I believe the reason your powerful pumps are having a hard time keeping up, is gravity.
If you don;t have a standpipe gravitational pull will always out power them.

https://hosting.photobucket.com/albums/i97/dstuer/sumps/.highres/045_zpsb22b6c45.jpg?width=320&height=320&fit=bounds

.

The tank above is drilled on the tank bottom.
To keep water level, .....level, ........ a stand pipe is needed to maintain depth.
You can see it on the right, and it uses two drain points as a redundant overflow in case one gets plugged up.

If power goes out, the tank or sump will only drain to the rim of the stand pipe.
And no matter what amount of pump-age, (as long as the diameter of the pipe can handle amount of flow) the tank will always maintain the same depth.
Although I have had tanks drilled on the bottom, I prefer drilling near the top (near the water surface) so I don't need a standpipe.
, ,
If it were me, and I wanted to get a 12,000 gph flow rate with the 2 pumps
I would drill (or have another hole drilled) on a small side, or the back of the tank, to add another flow aperture to the sump, to handle that size flow volume.

 

[Backfromthedead]

You may be better off leaving the drain wide open and having a potentially noisy open channel overflow imo. That could still flood but less likely than trying to run a full siphon drain/herbie without an e-drain. Even though your drain is on the bottom it is still technically a herbie style, just with a very low drain intake and no emergency drain.

I have a sorta idea if youre down for some plumbing work, just something i might consider trying if i were in your shoes. This could be accomplished without draining the tank:

If i read right, theres one 2" bulkhead and two 3/4" bulkheads in the overflow. Keep the 2" main drain as it is, but replace the 2x return lines with 2x 3/4" open channel standpipes to serve as your emergency drains. 3/4" drains cannot handle very much water but if you were to run the pumps conservatively i think 2x 3/4" pipes would serve adequately.

You could then disassemble the pump plumbing and instead use flexible vinyl hose or likewise to run the return lines up over the back of the tank and find some way to mount them to the rim of the tank.

OR:

set the 2x 3/4" bulkheads up as your full siphon drains, leave the valve wide open on the 2" drain and install a standpipe to serve as your emergency drain, and do the same with the return lines as in previous example.

 

[jjohnwm]

I like the set-up shown by duanes ^ here. I'm not a fan of bottom drillled tanks with standpipes, simply because it is possible...don't ask how I know!...to damage the standpipe or its bulkhead and have the entire volume of the tank drain out onto the floor. But a tank drilled on the sides or back, up near the waterline, can only drain down as far as the bottom of the drilled hole; I drill as close to the waterline as possible to minimize drain-down in case of a power interruption. This makes it easier to ensure that the sump can contain the entire volume of the drain-down.

It's foolproof. As long as the cross-sectional area of the drains leading from those drilled holes can carry a water volume that exceeds the pump's maximum flow, there is no way to overflow the tank. And there is no need to "balance" anything. I currently have a pair of 2-inch drains on a tank that has been flowing a realistic 1500gph flow rate and the water level in the tank when running normally doesn't even reach halfway up the diameter of the bulkheads. I'm now experimenting with the addition of a DIY diatom filter on this system, which will run on its own smaller pump, somewhere around 800-1000gph. This increase of at least 50% in the flowrate barely moves the water level higher at all, as a couple of 2-inch drains can flow vastly more water than even the combined total of the two pumps.

Turning off one or the other pump requires no fiddling, and creates no changes in the safety of the system. Neither one pump alone, nor the two running together, can overflow the tank. Having 2 or more drains acts as a safety, a blockage in one drain (unlikely with a 2-inch diameter) simply means that the other(s) carry all the flow. And multiple drains reduce the volume of water that drains down in the event of a power outage, since the normal water level in the display tank is only slightly above the eventual drain down level.

No valves required in this set-up, although you can if desired place valves in the return lines from the pump(s) in the event that you might want to fine-tune the water flow rate. I don't bother with that, because I don't have any reason not to use full flow, but if you are a fan of complications the option is there.

Now, the fly in the ointment: noise. As far as I can tell, the sole reason for the existence of all the complicated overflow designs...Herbie, Bean-animal, who-knows-what...is that they run much more quietly? And, I suppose, if one is using an undrilled tank with HOB siphon-type overflows (but the very idea of such a thing makes me ill). These supposed "improvements" force you to figure out work-arounds just to get your tank to run properly, to balance the flow rates, to provide emergency solutions to problems that only exist because of the so-called improvements. Look at the suggestions made by Backfromthedead ; they sound like they would work, but what a PITA just to correct the flaws in that original design!

Top-drilled overflows seem to run much more quietly than standpipes. My set-up has a vertical wet-dry filter right beside the tank into which the overflows drain. The main mechanical filter for the tank is right at the top of that tower, and can be swapped out in seconds. Bonus: if you get lazy and allow the mech medium to go uncleaned long enough to get clogged...the noise level rises dramatically as the water overflows the mech chamber and goes directly onto the wet-dry section, alerting you that it's time to clean!

So....here's what I would do if this tank were mine: turn off everything. Drain the tank down below the level of the weir and dry out the overflow chamber thoroughly. Remove the bottom bulkheads and silicone pieces of glass over the holes, or cap the bulkheads; either way, you're done with them. Drill holes in the back of the tank, either within the existing overflow chamber or elsewhere, right up at the waterline. Install bulkheads for at least a couple of overflows to the sump and whatever number of returns you wish, so I suppose two in this case. Attach all the plumbing leading to and coming back from the sump. When everything is dry and cured...rip that dang overflow chamber out and toss it. You get to keep all your pretty valves and straight white PVC piping with orange accents...but now your tank cannot overflow and requires no fiddling and diddling with flow rates, unless of course you just want to. In other words...it now works. You get more usable space in the tank as well, with fewer chunks of hardware in there taking up space and looking all techie-like. This is...or at least it should be...one of the benefits of sumps.

Admittedly, this is some work...and will be easier if you actually empty the tank and move the fish out temporarily...but it's a one-time PITA instead of the ongoing one you have now. It's very simple to set this up to pick up water from whatever level in the tank you wish, as well as with or without surface skimming if desired.

The tank can then be fun to own, which of course is the whole point. Is it fun the way it is currently? Good luck with whatever you decide!

 

[cockroach]

The only tank I ever had with bottom drain was a marine tank I converted into freshwater. It was plumbed for a berlin method reef so the bottom drain was connected directly to a canister filter and returned to tank as a closed system.

 

[Sassafras]

My theory is if I can balance at 100% power, the pumps cant spit any additional water.

Just remember, pump output will not remain constant and your balance point will change and require adjustment.

• When the water level in your sump rises (such as after a top off), flow from the pump will increase . When the water level in your sump falls (due to evaporation), pump output will decrease. This is due to the effect of changing head pressure on the pump.
• When line voltage changes, up or down, pump output will change up or down in response.
• As biofilm coats the inside of your plumbing, increased friction loss will decrease flow.
• After a power outage or surge, the pump controller may not return to its previous setting and pump output may increase or decrease.

These flow changes may be only slight, but if it goes unnoticed and the balance point is not changed to compensate, an overflow may occur. I think to guarantee against a tank overflow I would probably abandon trying to balance the flow, open the drain all the way and convert to a Durso standpipe to reduce the noise, but that's just me.

Your plans for a new CA aquarium sound awesome.