Return pump pumping too fast.

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Kelso

Aquarium Advice Freak
Joined
Oct 13, 2009
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Connecticut
My return pump I'm my sump is returning the water way too fast. I have a PVC ball valve on the return line. Right now it's running, but the valve is almost fully shut and I don't see much flow in my sump tank. If I turn the valve open from where it is the slightest bit, my overflow fills and the return eventually runs dry. I have a pump rated for 591 gph. My intake line is 1" PVC, as is the return line. The bulkhead is flush with the inside of the 1" PVC. I also got 2 1" outside circumfrence siphons for my overflow. Is it bad to restrict the flow of the pump that much? How can I get more flow? Would putting a powerhead in lower tank help? If I increase the size of my intake pipe, do I need to increase my return pipe?
 
I few questions: how big is the tank, and how big is the sump?

I only have a little experience here, with 2 125s both with 30g Oceanic sumps, but it's always a balance between the capacity of the overflow (length of the slotted opening) and the GPH of the return pump. If you open the ball valve all the way and it runs dry, then your overflow can't handle the GPH output of the pump. It's not bad to restrict the OUTflow of the return pump; it's bad to restrict the INflow (if you are running a submerged pump, generally you can't restrict the inflow).

Both the tanks I work on have 3/4 ID returns and 1" or 1-1/4" sump supplies, but there's always a bottleneck on the bulkhead down to 1" so I don't see much of a problem there, I think the problem lies in your overflow capacity. Throttle back the ball valve, starting at full, until you get a balanced level in the sump.
 
do you have the diffusers on the outlets or open bore plumbing?

I have a 45g tank with a sump capable of 175g tank filtering, I have a 950 GPH pump on it, I also have a CPR 100 box I believe on there, I am unrestricted inlet and outlet with the same ball valve on there at full open and I dont suck dry at all.

I think your overflow might be too small to handle the pumps GPH, This is my first sump system and i had it paired with the pump at the store I bought it from.

Here is a link which might help you a little more
its for the info not saying go buy their box, they just have great info on the overflows,pumps and sumps.

http://www.cpraquatic.com/pdf/csselection.pdf

basically compare their boxes on the chart when you find your pumps GPH and compare to other boxes even your own and go from there.

are you running a 2 outlet overflow box and still sucking dry or is there just 1 supply to the sump?
 
I made it all myself. Here are some pictures, the tank is a 46 gal bow front and the sump is a 12 gal bow. Im not sure what diffursers are so no I dont have any. So from my understanding I need to increse the size of the container of the overflow on the inside of the tank?
 
On another note, I think you would be better off getting a real overflow from CPR or Eshopps and make sure it's rated above your pump output. Remember you could always adjust the supply volume with the valve while leaving your return valve open. It's ok to restrict the return with a valve (I personally don't like too) but you have to be careful not to exceed the pumps head max head height. What model quiet 1 pump is that? From looking at the photos it looks like your tank can't handle the sump volume should the siphon break.
 
What in the world are you talking about?
If you have for instance a Mag 12 in a sump like this

img_1075778_0_f1edb023c1e374209ff0ebc3b955adc3.jpg


The inlet doesn't have a ball valve on it or anything to restrict the intake flow. If it were a pump exterior to the sump, you could put a valve on it of something to cut off the flow, but this would be bad for the impeller and cause failure.

On that note, I have a question about the picture of your sump. It looks like your overflow pipe coming in goes through bioballs, then the pump intake is actually piped to the other corner of the tank through a vertical and then horizontal pipe? Does that pipe then elbow down back below the water or something, or what?
 
You meant the suction side of the pump, I thought you meant the supply water into the sump. Now I understand what you were saying
 
I have no baffles. The pipe runs up like that so if I loose my siphon, for some weird reason, the pump will only pump that much water into the tank. The 90 reduses noise. I built my own trying to avoid costs of overflow box. The concept seemed easy, buy that may be what I have to do. The pump is a quiet1one mod. 2200. It's rated at 581 gph.
 
Your pump is just pumping about 300 GPH max maybe less because the output should be 3/4" Inner diameter pipe or tubing. The 1" is adding head pressure to the pump reducing it's output volume. Which definitely leeds to the feed being big time deficient. a 1 inch PVC pipe gravity fed is rated for 960 GPH so if you figure in the bends and other obstructions in the design you should at least be getting 600 gph. What you can do for a test is create a direct siphon from the tank to the sump with valve installed so you can control the flow and see if your pump can out pace the supply, I believe this will show you that there is a big issue with your DIY overflow. One thing you should consider is installing a gate valve on feed to the sump because it is a real PIA to adjust the level with the ball valves.
 
Ya, the ball valve is a big pain in the butt. I'm definatly going to redisign the overflow using bigger, rectangle pitchers. I'm going to take my time on this one. If all else fails, I guess I'm gonna have to buy a factory built one. Thanks guys.
 
So I redisigned everything. Made two 1" intake lines and added another siphon as well. The flow is much better. My only question is when I go to bed and wake up the next day, the water level in the return pump section goes down quite a bit. Not enough to run it dry but if I waited a few more hrs I'm sure it would. Adding about a half a gallon of water brings it back to the right level. I just wanted to make sure this was evaporation and that adding a little fresh water everyday was the right thing to do?
 
Thank you. I assume it shows in the return chamber because of the overflows/baffles?
 
If you can make the return chamber of the sump as big as possible otherwise you'll be topping off everyday and sometimes twice a day (I made that mistake with my first sump by making the return chamber too small, it gets to be a PIB topping off once or twice a day everyday) just to keep the pump submerged. The best thing to do if you can swing it is install an ATO, it will keep your salinity from any major swings and save your back.
 
The intake tube on the suction side of the sump is what is causing you to have to top it off daily. I understand your logic behind it, if you lose the siphon on the U-Tube your pump would overflow your DT. But have you ever lost your U-tube siphon? If you design it right, you should never lose it unless someone pulls the tube out, the water levels in the overflow buckets on either side should stay at the minimum should the tank level lower, etc. Your DT water level remains where it is at all times because of the overflow level, and your sump will lower due to evap. What I would do is lower your overflow buckets in the DT so that the water level is a little lower, then remove the intake tube on the suction side of the pump, and lower the level of the sump (or raise the pump). Then test your setup by purposely pulling the U-tube and make sure that the pump doesn't overflow your DT. Then set it all up again and turn the pump off to make sure your sump doesn't overflow due to backflow through the pump. If it's designed right, you should not have to worry about overflow of either tank. If not, it's a disaster waiting to happen.
 
Since those first pictures(which I think you may be refuring to)I have changed the design a little bit. Here are some pics of the changes. I think Inferno is right, my return chamber may be too small. What is an ATO? I am very interested.
 

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