Help with return pump sizing

[guitar8222]

I am going down to my basement from my 75 gallon. I calculated my headloss around 16 feet. (11' vert, 20' horizontal plus fittings) I am restricted by my tank which has a 1" bulkhead for the return. It is handling around 700gph now without any issues and I would like to keep it close to that. (my pump is a 40rlxt 1200gph)

I want to get a reeflo pump, but I am not sure what to get. I will be adding a frag tank to the system as well as a refugium which will feed off the line as well. I was thinking that I could always recirculate water back into the sump from the frag tank or refugium if my flow is too great.

I was thinking of either the Barracuda or the Hammerhead. Am I spec'ing this out properly?

[Geoff]

i will look, but i doubt a either of those pumps is what you want. looking at the flow charts for those pumps you are wasting gobs of flow using those pumps. those pumps are high flow, low pressure pumps. they are intended to be used in CLS's and not as return pumps. you need to be looking at the high head low flow pumps. the Tarpon looks like the pump you want. its chart shows a flow of 768gph at 16' of head pressure. horizontal distance is insignificant when calculating head pressure. at 16' of head pressure the Tarpon is only using 188w while the Barracuda/Hammerhead are using 237/345.

the other option is to go to an even higher head capable pump and run an eductor on the outlet for a huge increase in flow. @2000gph of flow out of the nozzle with only 400gph of flow through the sump.

G~

[guitar8222]

I was looking at the tarpon but if I split my return to any other tank I will not have the flow I want. I was thinking about the wahoo but it seemed like more people are using the barracuda.

I was also worried about having a 3/4 return with that much flow and pressure. It seems like I would have to use schedule 80 for my return since it is such a small pipe.

[ckusnierek]

Bigger is always better and you can throttle the output back if it's too much flow for your drain.
Then you have more option.. If you add a frag tank, get a bigger tank, or what ever.

I am gettign ready to run a Dart for my return and build a manifold to supply the main display, frag tank, CaRx, Carbon Rx, Phosban Rx etc..

Look into the new blackfin pumps from reeflo. The BF2500 looks like about 1000gph at 16'

Also the pressure rated Iwakis,Bluelines and Panworlds...

[guitar8222]

They have a special price going on the blackfins but I don't like that union that is built into the pump.

When people use the tarpon/wahoo pump do they upsize the pipe to 1" right away.

[Geoff]

you can always upsize the input or the output. it just cuts down on the flow loss due to friction. i used 2" pipe for all of my 45 foot runs to and from the tank from my return pump, and the Ampmaster 3700 in the basement.

explain split the return. this is generally not a good idea. it is very difficult to balance the load between tanks, and if anything were to get clogged in one the other will get all/none of the flow and flooding is sure to happen unless you set the entire return flow equal to the drain for for the lowest drain in the system.

Darts are not that great on manifold setups unless the manifolds are entirely made out of 1.5" pipe or greater like the output for the Dart. Darts do not like any head pressure at all and total flow drops dramatically when you restrict the flow on the output at all.

it is very important to match the pump to the task, or you will be wasting watts or flow for no reason and will lead to unsatisfactory results.

remember going up in size on the outlet will lessen the effect of friction in the pipes, going down in size dramatically increases the effects of friction. going with smaller nozzles on the outlets will also significantly increase the amount of head pressure experienced by the pump.

for my Ampmaster 3700 i had 1 1.5" inlet and 2 1.5" outlets just to make sure i am getting as close to the rated 3700gph of flow the pump is rated to.

Chris- using a Dart for that purpose will lead to less than satisfactory results. a Dart will not push water through those reactors without significantly killing its flow rate. a high pressure pump would be much better, that way you can adjust the flow rates for each entity because the back pressure can build up equally among all devices. until the back pressure is equal you will not be able to adjust the flow equally between devices. water will alway take the easiest way out. these will be the returns and not through the reactors. then there is the problem that the reactors are a variable load. as they fill with bacteria the resistance will increase causing a change the flow dynamics of the rest of the devices. you will find that you will need to change the settings almost constantly in order to maintain the flows you want. you will have a much better chance of this succeeding if you use a pressure pump that can force the water through the devices instead of reacting to the load of the devices.

G~

[guitar8222]

Originally Posted by Geoff

explain split the return. this is generally not a good idea. it is very difficult to balance the load between tanks, and if anything were to get clogged in one the other will get all/none of the flow and flooding is sure to happen unless you set the entire return flow equal to the drain for for the lowest drain in the system.

So if I have the pump feeding off of my main sump and I tee off to a refugium in the basement that has an overflow hole near the top which leads back into the sump would I really have an issue? My tank would feed back direct to the sump as well.

I figured I will have to dial in the feed to both tanks with a ball valve and as long as my overflow in the refugium is large enough to cover the full flow of the pump how could I have a flood?

I guess I am not thinking this out right.

[ckusnierek]

Thanks for the fluid dynamics lesson Geoff. I never looked at it that way...

[Geoff]

Originally Posted by guitar8222

So if I have the pump feeding off of my main sump and I tee off to a refugium in the basement that has an overflow hole near the top which leads back into the sump would I really have an issue? My tank would feed back direct to the sump as well.

I figured I will have to dial in the feed to both tanks with a ball valve and as long as my overflow in the refugium is large enough to cover the full flow of the pump how could I have a flood?

I guess I am not thinking this out right.

the question is what happens if an outlet gets clogged? lets say the refugium output from the pump gets clogged with a snail that has managed to take a ride down the overflow then into the pump and got wedged in the outlet of the fuge significantly cutting the flow into the fuge. the pump is still going to be pumping all it can. the extra water that was going to the fuge will now go to the display. will the overflow from the display handle the extra flow caused by the snail blockage?

if you want to tee off the pump output to go to 2 different places than you have to make sure that the overflows for those places is capable of handling the entire rated flow for the pump at its given head height to be safe. in your example that means that the fuge will need to have an overflow capable of handling the Darts maximum flow at the head height of the fuge. could be in the thousands of gph. that would make for a very large overflow.

G~

[guitar8222]

So how does everyone else feed more than one tank? Would I have to have the display return into the fuge?

I drew up something quick in paint to show you what I was thinking. The purple circle things are ball valves.

[Geoff]

they feed their fuges with the drain from the display, not from a split off the return pump. the other way is to use a dedicated pump for the fuge.

snails get stuck in ball valves all of the time, not a reliable setup you have drawn. if a snail gets stuck in the ball valve going up to the display you WILL get a food in the fuge. the 1" drain can not handle the flow that a Dart would put out at such a low head pressure. in the neighborhood of 3000gph.

G~

[Neuticle]

Yeah, gate valves will save you electricity too, they are the lowest friction loss valves commonly avail.

If you want to calculate true head loss, I can hook you up with a beast of an equation that will even calculate necessary pump head pressure, and power rating. But if you're not mathematically inclined, I'll just leave it alone.

[guitar8222]

Cool that's what I wasn't factoring out right. I think you are right about the tarpon. I think 700 gpm at that much head will be great then since I won't bee feeding the fuge.

Now should I split the return from my tank into both the sump and fuge to slow down the flow through them? Thanks again Geoff (and everyone else)

[Geoff]

honestly i would ditch the "fuge" and make it into an empty settling tank. i would make whichever entity is larger, the sump or the fuge into this settling tank. have the display drain into this tank. leave it as open as possible. the drain from the display going in on one side and the drain to the sump on the opposite side. this will allow the water to slow down as much as possible. this will allow all detritus to settle out into this tank for quick siphoning once a week during water changes. any really small bits of detritus will go into the sump where the skimmer will pull it out. you might need to do a quick spot clean in the sump also, but there should be very little detritus in there.

think of what you are wanting the tank to really be, do not be confused by good feely stuff, that will not help you long term.

have you thought about eductors on the return nozzles?

G~