Return Pump question, big dilemma need opinions

[harryk]

Hello all,

I have completed plumbing my new 215 and aside from 2 small leaks it went pretty smoothly with no major catastrophes. Now to my dilemma. I have a 75G acrylic sump and the return pump i am using is the Blueline 70D 1750GPH rating. When the pump is on and running with the ball valve completely open it drains the return chamber of my sump almost dry and sucks air. I have to close the valve 3/4 of the way in order for it to keep water in the return chamber. I thought of diverting water back into the sump chamber from the pump in order to keep it full, but IMO i think this would be a big waste of a nice pump. The pump is currently pushing 1400GPH and my sump cant keep up with it. I was thinking about getting a smaller pump the Blueline 55D it will push about 1000GPH with the way my tank is plumbed. I'm very frustrated and i would love to keep the 70D but i think it might be too powerful. All opinions and advice greatly appreciated.

Harry

 

[MikeNapoli]

You can do a couple things.

• You can add more water to your sump. When my pumps are off my sump is 95%full. When it's running all that water goes down to the "opperating level". Not sure how else to explain this.
  
• You can go with the smaller pump. You've already said you didn't want to, but it's an option
• You can "T" off more lines and run things like a calcium reactor, phos reactor, etc.
• You can "T" off and feed your skimmer or just have it go back into the return area.

 

[DaveK]

There are a couple of other areas to check.

Assuming you have a more or less standard 215 gal reef ready tank, the pump you have may be far too large. Usually you can figure a single overflow can process about 600 GPH, and since a 215 gal tank usually has two, you can process about 1200 GPH through both overflows. A Blueline 70D 1750GPH is going to over drive the overflows, and either cause a flood or run the sump dry.

If your sump is a DIY project. Also check your sump design. Most likely the return chamber is far too small. Often the return chamber needs to be 1/2 to 2/3 of the sump. Yes, I know that sounds like a lot, but it needs to contain all the water needed to get the overflows in the tank going at full flow. this can be a lot of water.

Be very careful about adding additional water. The sump must be able to hold all the "live water" in the system. This is water that will keep draining if the pump is stopped. This is critical if you want to avoid floods due to the pump stopping.

 

[harryk]

when the pump is off and all the water drains into the sump ( all the live water) I still have about 6" to spare, but i don't think that will solve the issue. I will try it tonite, but i think i will have to go with a smaller pump. The only reason i went with the 70D is because i wanted to be around 1200-1400 with head loss. I'm at 1400 right now and in case i needed to add anything later like a CA reactor.

Harry

 

[Phyl]

If the plan is for eventual growth then I would create a manifold and divert some of the water back to the first chamber of the sump (not the return chamber as that would likely create microbubbles in the tank). Since you really only need 1200gph max going to the tank that shouldn't be a problem. It would be like plumbing in the Ca/PO4/Carbon/Kalk/?!? reactor in advance.

 

[harryk]

If the plan is for eventual growth then I would create a manifold and divert some of the water back to the first chamber of the sump (not the return chamber as that would likely create microbubbles in the tank). Since you really only need 1200gph max going to the tank that shouldn't be a problem. It would be like plumbing in the Ca/PO4/Carbon/Kalk/?!? reactor in advance.

Would that solve the issue of the return chamber draining??

 

[MikeNapoli]

I agree with what Phyl said, creating a manifold for future projects or reactors would be awesome. But also having 6" left in the sump is fine and all but that's your first issue Try only having 3 or 2 inches left. I have about 2 inches when my pump is off. This also allows me to make larger water changes. When I do my changes i suck the sump dry leaving only the refugium and it works out to my 32 gallon water change.

 

[harryk]

I agree with what Phyl said, creating a manifold for future projects or reactors would be awesome. But also having 6" left in the sump is fine and all but that's your first issue Try only having 3 or 2 inches left. I have about 2 inches when my pump is off. This also allows me to make larger water changes. When I do my changes i suck the sump dry leaving only the refugium and it works out to my 32 gallon water change.

I don't have any issues with leaving only 2-3" , but how will adding more water make the return chamber not run dry, i'm a little confused.

Harry

 

[MikeNapoli]

Well when I was doing my plumbing. I was told that you fill the sump up and mark a line on where you'd like your opporating level. They you turn your pump on and add water to the sump until your running at opporating level with your pump on.

Then you shut your pump off and pray you don't over flow.

Mine worked the first time.

But still, technically you should have a max of 1200 gallons per hour going up since that's all it can handle going down. Since you used flex pvc you're not loosing too much head pressure. I guess going with the small pump wouldn't be so bad.

Unless you went with Phyl's manifold idea.

 

[Phyl]

LOL, Mike. I've always heard it the other way around. Fill your sump to as high as you can stand it with your system off, mark a line. Then turn it on and mark the running level. This is the level that you will "top off" to while your system is running.

The more water in your sump, the more water should be in the return chamber when your system is running. Hopefully.

 

[MikeNapoli]

LOL, Mike. I've always heard it the other way around. Fill your sump to as high as you can stand it with your system off, mark a line. Then turn it on and mark the running level. This is the level that you will "top off" to while your system is running.

The more water in your sump, the more water should be in the return chamber when your system is running. Hopefully.

Sounds like your way is safer.lol.

 

[malulu]

When i was using a regular tank as a sump, I used the same methods as Phyl described to mark the "running", and "top-off"

also started to take water out to a bucket on the side, just to know the lowest point before the return pump starting to suck in air... then mark a line a little bit above that as the "lowest"

then label them as below [...] so my wife and kids know what it mean when i am not around.... (much better than the "running", "top-off"...etc.)


[must ADD water now!] for the "lowest" mark
[normal low point] for the "top-off" mark
[normal high point] for the "running" mark
[must REMOVE water now!] on about 1" above the "running" mark

i now use a pony tank and fully auto-top-off, auto-water-change...etc.

 

[Daniel]

I would go with Phyl. That is how I have been doing it for more than 14 years.
Daniel

 

[harryk]

i like Phyl's idea on the markings and i plan on using them. I still havent decided on what i'm going to do with the pump. I'm leaning towards selling it. It's a shame that i'm even thinking about selling it. It ran for 15 minutes so i can check for leaks. I am so disgusted right now.

Harry

 

[Daniel]

Look what I would do is put a tee coming out of your return from the pump. Put two gate or ball valves on each side so you can control the water flow going back to your tank at wide open and to your sump in the first chamber so this way your return camber stays at the water level you like. All so you can throttle back the Blueline Pumps by 1/3rd with no harm to the pump. I know the ins and out of there pumps very well. It is nice to have a pump that is bigger because over time you will see that you will open the valve a little more. You can tune much better than a small pump. You can do add on with a bigger pump.
Daniel

 

[mikem]

How high is the water level in your display with the pump running?
How tall is your baffle to the return side of your sump? Can you get a pic. of your sump?

The reason for these questions are.
I am pumping 1900 gallons to my display with only one overflow rated at 700 gallons returning water down to my sump. My water level in the display rose 1/2 an inch higher then normal. My return chamber in the sump was running dry. I was gonna give up the idea of running all that water up to my display.

I started notching my return baffle and it started working better and better.
I've been running it this way now for awhile with no problems.
I'm not an expert at this, but it worked for me.

 

[CaptainAhab]

Might be an obvious question but your overflows are 1" (2 of them) correct? They flow at 600 GPH per. Is all your piping 1" also? I've seen people try and use reducers to reduce the pvc to 3/4 thus reducing the flow from the overflows and whacking out the entire calculation

 

[harryk]

How high is the water level in your display with the pump running?
How tall is your baffle to the return side of your sump? Can you get a pic. of your sump?

The reason for these questions are.
I am pumping 1900 gallons to my display with only one overflow rated at 700 gallons returning water down to my sump. My water level in the display rose 1/2 an inch higher then normal. My return chamber in the sump was running dry. I was gonna give up the idea of running all that water up to my display.

I started notching my return baffle and it started working better and better.
I've been running it this way now for awhile with no problems.
I'm not an expert at this, but it worked for me.

The water level in my display is roughly at the midway point on the top slots of the overflow about 1" form the top of the tank. I have attached a pic above that i have which shows the return portion of my sump. it's the best pic i can provide until i can take one toniteI wanted the fuge section baffles 10" high. The idiots that built my sump left the last baffle before the return chamber 2" lower as you can see from the pic. so it automatically lowers the water volume in the reutn chamber 2" lower then the rest of the sump. If there was a way to icrease that baffle would it help or maybe is there another way that to increase the volume of water that is in the return chamber?? And i do not want to restrict the size of the drains, they are 2 1" drains. I hope this makes sense

Thanks
Harry

 

[Daniel]

Your return chamber is way to small for that pump. Just tee it off and run on of the tee return back to the first chamber of the sump that will help keep the sump full. Just make sure you put a valve on it so you can control the water flow back to your sump.
Daniel

 

[mikem]

I agree with what he

said.