closed loop pump question

[douggiestyle]

im working on my closed loop and im having pump selection problems.

am i better to use one pump rated at 3000gph at 400w

or two 1700gph at 150w

my first impression is spend an extra $100 and get 400gph more at 100w less

but i just dont see people doing this in their designs

so am i missing something

[joshuaroot]

wow thats alot of gph for a closed loop what size tank is it and how many returns you having back into the tank?

[douggiestyle]

my plan is for four apx 100g tank. not including sump which will be apx 30g

the pump sizes and ratings are more for the point.

most likely some where around 2000-2500. but the specs are about the same ratio.

[joshuaroot]

i would say one pump but thinkin about it, i might be an advantage to have two pumps if u hooked them up separately. in case of to much flow just shut one off. or not enough turn both on. i dunno i'd prolly just go with one pump tho.

[kgross]

That is a very good question. Me I would suggest going with 2 pumps over one, that way you have a backup in case one pump fails, plus you will get more flow with both pumps on. Another great advantage to dual pumps rather than just one is that you can have one pump on 24/7, and have the other pump only come on with the lights, that way the tank has a slightly calmer period at night just like the ocean, and then with the lights on the current comes up. Plus you save 1/2 of the electricity from the second pump. This is actually what I am doing on my 180 I am setting up, I have a sequence 3800 gph pump that goes through an OM 4way valve, that is on 24/7, and a dolphin 3800 pump that that is on a timer with the lights.

Works very well.

kim

[douggiestyle]

nice idea k, i like it.

sorry i didnt have the exact specs yesterday.

specifically im looking at gen-x pumps.

pcx-40 1190gph @ 110w
pcx-150 2131gph @ 480w

it seems more sensible to have (2) pcx-40 a total of 2380 gph @ 220w

and only about $25 more

[newnano]

i would look at the sequence dart or the snapper (2500gph). it requires larger pluming sizes but the wattage is only a fraction of those pumps and there is no heat transfer because the motor is sealed and not right next to the water like the magnetic pumps.

i have the sequence snapper and love it!!
http://www.premiumaquatics.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=SQ-REEFLO10-SW&Category_Code=Sequence
or
http://www.premiumaquatics.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=SQ-REEFLO10-SW&Category_Code=Sequence

[douggiestyle]

thats sweet.

[newnano]

yea. i love it. you can reduce those in/outakes per the mfg by .5in i have mine going from 1.5 bulkhead to the intake and then out 1.5 in and split to two 1" bulkheads.

im putting it on my cl for my 120 but not reducing it so i get the max

[douggiestyle]

so you have a 1.5" bulk head going to 2" at the pump intake?

then your running 1.5" as a manifold with 1" take offs? are you using some type of alternating circulation system, like seaswirl etc?

[newnano]

yes. per the mfg you can reduce the sequence pumps. they used to provide the reducer when you bought them.

yes 1.5 in going up to two 1in bulkheads and each bulkhead has 3/4 in lockline split twice. so in the tank there are 4 -- 3/4" lockline outputs.

when i hook it up to my 120 gallon i will be going with 2in intake and the manifold will be 1.5 in output to 4 ---1in bulkheads. this along with my 100pxx panworld as a return i should have enough flow. if not then i will get hte sequence dart which will swap out with my snapper identically

[RichConley]

You can reduce the sequence pumps, but you WILL get less flow. How much less? Who knows.


Douggiestyle, based on your W numbers, it looks like you're using big pressure rated pumps. I'd recommend a dart for that tank.

[kgross]

You can reduce the outlet of any pump, but it will reduce the flow. You should not reduce the inlet to the pump though because you could cause a enough friction to create a low pressure area in the impeller and cause cavitation which is very rough on the pump.


For a closed loop get a circulation pump not a pressure pump they put out more flow, and take less electricity than pressure pumps. Sequence and Dolphin pumps make very good closed loop pumps.

Kim

[newnano]

i agree with not reducing the inlet of a pump with the exception of the sequence pumps. after seeing that the mfg previously provided the reducer i tried it. i still get tremendous flow out of that pump. i am sure that is it harder on the pump than if it was left with the original diameter piping for sure. but ive been running it this way for 6 mos with no issues. now that my new tank is drilled for a 2in bulkhead i will be returning to the orig and cant wait to see what kind of flow i can get

[RichConley]

<a href=showthread.php?s=&postid=8505644#post8505644 target=_blank>Originally posted</a> by newnano
i agree with not reducing the inlet of a pump with the exception of the sequence pumps. after seeing that the mfg previously provided the reducer i tried it. i still get tremendous flow out of that pump. i am sure that is it harder on the pump than if it was left with the original diameter piping for sure. but ive been running it this way for 6 mos with no issues. now that my new tank is drilled for a 2in bulkhead i will be returning to the orig and cant wait to see what kind of flow i can get

You're reducing the input how much? And what is the output reduced to?

[newnano]

in to 1.5 in and the output is 1.5in for two feet then gets split into two 1in bulkheads

[kgross]

With that restriction on the output you will not have to worry about the 1.5 inch intake causing a cavitation problem. But with your sequence pump you are cutting your flow by atleast 25% if not even more. Your 2 inch pipes are the same as a 1 1/4 inch pipe which is a pretty good restriction depending on the length of the pipe. If you change out your plumbing to use 2 inch from your 1.5 inch bulkhead to the pump and then from the pump right up to the 1 inch bulkheads you will get a lot more flow.

[godiver]

I have a Hammerhead pump that I was going to setup as closed loop manifold with 1" manifold around tank and 10 outlets would this be too much? Where should I start the 1" adapt right out of 1.5 outlet or can i bring 1.5" up to tank lip and move to 1"... Also a intake question I have an extra 1.5" bulkhead on underneath of tank in a overflow can I use that for intake a few inches up with a strainer? or am I better off bring intake over top lip of tank (I cant drill any other hole as of now tank is full)

[kgross]

The first thing is that your 1 inch manifold will restrict the flow from that pump a lot. If you want max flow out of that pump go with atleast a 1.5 manifold or even better a 2 inch manifold.

What I would suggest you do is go up over the top of the tank with a 2 inch pipe, down to the pump, then bring 2 inch pipe up to the top of the tank and then T off to 1.5 inch pipe to run around the tank, then T that manifold off into the 1 inch outlets.
The RC head loss calc does not have the hammerhead, but if you use the SEQ5200 which should be close to the hammer head if you just use 8 feet of horisontal pipe, and 5 elbows (does not include the manifold which will decrease flow more.
Anyway 8 feet of 2 inch pipe gives 5000 gph,
8 feet of 1.5 drops it down to 4800
8 feet of 1 inch drops it down to 2200 gph.

So if you only want 2200 gph save your money on the hammerhead and get a dart, or even a smaller pump

On your bulkhead in the overflow, that is not a good idea for your closed loop intake. With the 5000 gph flowing over the overflow you will have lots and lots of air in the water so you will be sucking lots of bubbles into your closed loop so you will have lots of micro bubbles comeing out of it. Plus something happens to your return pump, you will end up running your closed loop pump dry and burn it up also.

Kim

[douggiestyle]

go diver. if the bulk head is coming up from a hole in the bottom of the tank. yes come up a few inches for the sand. i would say you should be fine as long as you are a about six inches from the surface of the water. if you get to close to the water surface then yes, just like kim decribed, a whirlpool effect will take place drawing air from the surface creating micro bubbles.

[douggiestyle]

<a href=showthread.php?s=&postid=8505021#post8505021 target=_blank>Originally posted</a> by RichConley

Douggiestyle, based on your W numbers, it looks like you're using big pressure rated pumps. I'd recommend a dart for that tank.

you are right rich they are a pressure rated pump.