Why do we assume a large return pump is needed?

Herbert...so you think on a CL I should not account for static head when im trying to figure out what my CL pump will be running?

You know this seems like common since to me now...I cant believe I didnt think about it before. Really if you are flowing 1000 gph through your tank and only have a 500gph on your skimmer it would seem to me that its missing 50% of the water to skim. Thanks for this thread!

And you are so right about the "next tank" syndrome. Hell i dont even have my new one yet and I am already day dreaming about other tanks I can fit in my tank room :lol: Damn this hobby!
 
Static head is the distance between the surface of the 2 different bodies of water in an open system, i.e. your sump water level and your tank water level. Since the water level of the tank is the same for both the intake and return on a closed loop, there is no static head.

You can easily prove this theory on your own, as I once did accidentally. I had a closed loop that returned to a manifold around the top of the tank and was doing maintenance on the tank. I was doing maintenance one time and forgot to close the valves on the closed loop pump. When I removed the manifold via a union at about tank rim level, water squirted up about 2 feet in the air.

The reason this happens is because gravity is forcing the water down towards the pump intake with the same amount of pressure it takes to raise the water, so it balances out and you have no static head. You do of course have to account for friction losses.
 
Well some-a-bich...I learned something today :lol: I thought static head was ANY vertical run from the pump so I was figuring my CL using static head like I did with my sump. It makes total since why its not like that on a CL...very :cool:
 
So you're saying that it makes no difference where you mount your CL pump, it'll always have little head pressure? If your intake for your CL was at 4" from the bottom of a 24" tank, and your outputs were say... 4" from the TOP of the tank, you'd only be seeing about 16" of head pressure? EVEN IF, your CL pump is underneath in your stand?

Interesting...
 
It doesn't matter where your intake or outputs are. Static head is the difference between the surface water level on the intake and output. So on a closed loop, it will always be 0, even if the intake and output are 16" apart like you say. And it doesn't matter where your closed loop pump is. I've always kept mine under the stand.

You still have to worry about friction loss, which can be as much or more than static head if you don't plan your plumbing carefully. The main thing here is to use the proper pipe size for the amount of flow you have. If your plumbing is oversized a bit, then even a few 90's aren't going to cause you to lose too much flow.
 
From what I gather it wouldnt even be that much. The pressure of the water in the main tank is pushing the water through the drains 4" off the bottom. Almost like using forced induction of a car engine....is that correct guys? So the pump doesn't have to work as hard and it doesnt add up the back pressure like if it was just sucking the water from a sump and putting it up in the tank.

I think...
:D
 
NOLACLS - You got it. :thumbsup:

I like the forced induction analogy - now I can start telling people my tank is supercharged. :D
 
Boost ownes joo :cool: :lol:

Thats going to be the next big thing...little under water blowers for the intake of you pump :lol:
 
how did i spend $150?

well... spaflex costs a lot, and i used a lot of it. unions cost a lot, and i used a lot of them. elbows and tees really start to add up. I did 1 1/4 from my two overflows, which both meet at a 1.5 tee, which then enters the back of my stand, and then splits again with another 1.5 tee to go to my refugium and sump. ball valves for refugium and sump entrance: 1" for refugium, 1.5" for sump. 1.5" ball valve is $10! i know the ball valve for the overflow is risky, but it does wonders for bubble and noise reduction. i've also got a float switch with a timed relay on my return pump, so i'm fairly safe. I built a 1 1/4 pvc overflow, that came in at about $20. it all just really adds up.

i have it running out in the garage right now. since i've pretty much worked out all the bugs, i think i'll just keep what i've got. i definately don't need more flow since i've also got 4 mj 1200s. i guess my next tank will be done differently.
 
Well, I'm glad you started this post. I've been thinking about this for about a month, and all this talk has made me decide to go for it. I ordered a BL-1100 today and should have it Friday. I'm going to use it for my return pump and go through my chiller to a single return outlet in the tank. Accounting for head pressure, I will end up with about 600-700 gph of flow through my sump, which is less than half what I have now. I may even play with turning the flow down even more, just to see if it has any effect on the skimmer.

Then I'm going to use a small powerhead to run my skimmer and calcium reactor, and move my Sequence pump to the closed loop and split it between the 3 remaining return bulkheads.
 
It was said to me to put the chiller on the CL. Since it doesnt loose to much flow and the pump will introduse less heat that the chiller has to chill.
 
I doubt any chiller has 1.5" in and out. --> Major losses due to head pressure.

Keep the chiller on the return line. There's a minimum and maximum flow that should be kept through the chiller. I'd guess a sequence pump is way out of range.
 
But you could "wye" off a 3/4" line and "wye" it back into the 1.5" line and use a gate valve to adjust how much is directed into the chiller...at least thats what I am hoping and planning on doing :D

OK I tried to get this to line up but its not...odd. The lines going in and out should be under the "wye" Pay no attention to the commas...thats just to push the line over.

What I am thinking is this
SEQ pump---1.5"----wye--------Gate valve------wye----OM4way
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,\____3/4" to chiller___/

If you restrict the gate valve a little the water should be forced to go through the chiller but not really loosing much flow because it ties back into the 1/5" line. You would just loose what the chiller restricts and some for the wye's.


I am no expert tho...does this seem like a good idea?
 
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My chiller wants 600-1000 gph of flow. I could run it off the closed loop, but then I would have to tee it off the main line, use valves to balance the flow, etc. IOW, the same situation I have now trying to use a big pump to run everything off the return.

I can see the logic behind running the chiller off a closed loop - you have less head pressure to deal with already, plus a generally larger pump, so that's better than using a larger, more powerful return pump that has to overcome not only the static head but also the head pressure from the chiller (which is about 8' for my chiller alone). But I don't want to deal with the hassles of trying to balance the flow, like I do now. Plus, the main thing I use my closed loop for is to blow across the starboard bottom and keep too much detritus from settling. I've been thinking about putting the closed loop pump on a timer to only run every so often, and I couldn't do that if the chiller was run off it.

The pump I picked is perfect for my application - I used one before on my 75g with the same chiller and a UV sterilizer, and I still got about 600 gph of flow out of it. And it only uses 70w, which is very impressive for a pump this size. It's very quiet and cool-running too. Now I wish I hadn't sold it with the old tank.
 
yes, a bypass is exactly the way I would do it as well. That way you could plumb the chiller off of the main line and have minimal flow restriction. You could even put unions and ball-valves on the in/out of the bypass so you can easily disconnect the chiller w/o even touching the closed loop. For cheaning or whatever. This method is how I plumbed a small $30 cannister filter chamber inline with my closed loop for water polishing. This way you can run most of your water through the main loop, and just what you need through the chiller, resulting in the least amount of flow loss possible.

Hi SunnyX,
Well, between my cousin's 125 and the 300+gallon by DNA, I would say that any pump that gives you at least 100gph is fine. An eheim 1250 is my favorite in this range...should give you about 200gph...just enough to keep the surface clear. The only reason I have come up with where low-flow might work against you is with refugiums mounted in the sump...they do better with a higher turnover. (Otherwise, simply putting a powerhead in the refugium to keep the water turbulent might be enough...but the macros do rely on pure throughput for nutrient export...moreso than skimmers). I mention this now because I dont know much about your system otherwise...
What do you plan on for the rest of your 180? A closed loop or in-tank flow pumps?
 
wholy chit chat macros - I am in the process of upgrading to a 100g from my 60g, and am learning lots from this one thread. Really - thank you guys!

I am planning on using a quietone 4000 for my CL. One in-port (1.5" or 2") and up five (0.5" and 0.75") outports. Maybe a quietone 3000 for return...
 
Due to all the bends, 90's etc. from getting the return line from the sump back into the tank, you'll be better off with a pressure pump. That would make the loss in head pressure a mute point. IMO, its much more simple to add the chiller to the return, then adding a wye to a closed loop. JMO, but I try to keep the system as simple as possible. I used to have 3 T4's pushing into an ocean's motion, closed loop, etc. etc., but it just wasn't worth the hassle. Besides, 1.5" fittings definitely aren't cheap, and there isn't an easy way t adjust the flow through the chiller with a closed loop. And 600gph is not a lot of water for a sump to handle. Whatever's clever, I may have a ton of equipment, but its actually very simple.

-Yam
 
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