Closed Loop

[nsamouroux]

Well I'll be damned. I didn't know about the gph rating either on the Hydors, but it does make sense... I wonder if it is brand specific or is that how they rate all powerheads (or at least the Tunze / Hydor / Vortec)? I was sort of wondering why my sump return pump is supposed to be pushing 3,000 to 3,500 gph at my head pressure while the k8 pumps are supposed to be at 3,250 gph but feel much weaker. I figured it was because the flow was spread out / conical rather than direct and focused with the sump return fittings... Interesting!

I'm definitely going to have to adjust the powerhead placement now... I still prefer the powerheads over a closed loop on my setup, but I have a 4' long horizontal overflow on my back panel whereas you have a peninsula setup. I'll try placing the K8s lower in the tank (about 8" above the sand bed on the back wall) and point them upwards so that the intake flow acts as a vaccum of sorts and then blows detritus upwards to the overflow. Thanks for sharing the summary of that discussion! It might be common knowledge for some other people, but I certainly didn't know that they were rated differently and never thought to use the intake flow to my benefit. Another day or two of tinkering ahead!

 

[roscoe]

I think the biggest mistake I made and what most everyone makes with the KORALIA MAGNUM series is the ratings. And it was finally pointed out to me today.

The KORALIA's are rated by FLOW which means passing through the flow pump. So if the rating is say 2700 that is 1350 in and 1350 out for total flow.

That is interesting to know. I don't think all PH are rated that way though.

 

[returnofsid]

I agree with Roscoe and actually don't think any are rated that way. A K8 is rated at 3250gph. It's going to push approximately 3250 gallons of water, per hour. James, I think you're maybe misunderstanding how it was explained to you. A powerhead rating isn't split in half. This would mean that a MJ1200, which is rated at about 300gph, is only actually pushing 150gph. I've emptied a 400 gallon kids swimming pool, in just over an hour, with a MJ1200. If the actual "flow through" were 150gph, this would have taken almost 3 hours.

 

[nsamouroux]

Yeah, I believe only prop-based powerheads would be rated like that, which is why I mentioned Tunze / Hydor / Vortec. I would think that since powerheads like the MJ1200 and other impeller-based units act more like a typical pump they would be rated for output only.

I'm now thinking that my four K8s would be best used low in the tank (just far enough above the sand to not suck it in) at 2' intervals pointed straight ahead and upwards towards the top of the front panel. This should create a rolling flow pattern that pulls from the bottom rear of the tank where detritus would collect and forces it up against the front panel where it rebounds to the water surface and then down my "shortened coast to coast" overflow. Should have the added benefit of not blowing the fine grain sand bed around

I can see why a closed loop (or combo closed loop / powerheads) would be best for Salty's peninsula style tank. It would be too great a distance to have powerheads on a single wall like with that 1200g tank mentioned earlier and still push it all the way back to the overflow. That would be about 15' distance for it to travel before it reached the overflow in Salty's case, it would be more efficient to have a closed loop on the bottom with outputs spaced throughout the bottom panel (pipes running under the substrate with nozzles pointed upwards? Locline?) to push the water towards his overflow.

 

[Saltyfish]

All prop-based powerheads are rated as flow, it does not matter the brand.

Since Paul asked me what a K7 is and I told him it was a powerhead by Hydor and his reply was all powerheads are rated by flow. I have looked around and sure enough everyone says flow on prop-based powerheads

Look at it this way a Dart Pump is rated at 3600 GPH output (I believe) that means they have to suck 3600 GPH in to output 3600 gallons so the flow rating is 7200GPH if you wanted to rate a pump as flow.

 

[CarlaW]

I would love to hear what the rep from Korallia has to say about that statement????
I am sure that the guy from OM loves powerheads!!!!

 

[returnofsid]

No, it would still be 3600 GPH. The pump isn't actually sucking, since pumps push, not suck, but being flooded, by 3600 gph of water. That same 3600 gph of water is being pushed out the other side. It's the same 3600 gph of water.

 

[nsamouroux]

I'm sure there's a certain bias there :lol:. His statement does make sense though, and I'm willing to believe there's a basis in truth to it. I'll have to look into it for myself though, but I think it's likely that a prop-based powerhead like the hydors, tunze, vortec, and MaxiJet pumps with the MJmod would be rated for overall flow. I'm inclined to believe it primarily because of the difference in percieved flow strength between my sump returns and the koralia powerheads I've always used...

 

[nsamouroux]

It would be easy to test an impeller type pump which is usually sealed like the MJ1200s to verify their flow rating by setting up a container drain test like you had Returnofsid. I can't really think of a way to verify the gph rating of a prop pump though, since there's no real way to isolate the input from the output...

 

[nsamouroux]

I'm thinking of it along the same lines as skimmer ratings... Most ratings are an ideal situation under specific conditions, but since I've never seen the conditions specified on the different pump ratings it does bring up an interesting question on how they come up with the numbers.

 

[Saltyfish]

That would be about 15' distance for it to travel before it reached the overflow in Salty's case, it would be more efficient to have a closed loop on the bottom with outputs spaced throughout the bottom panel (pipes running under the substrate with nozzles pointed upwards? Locline?) to push the water towards his overflow.

Actually it is more efficient to have the 45 degree nozzles on the bottom pushing away from the overflow, or towards the sides and having a powerhead at the top far end pushing towards the overflow. From this you get a circle motion in the tank.

I could replace the powerhead on the far end by routing my return lines to the far end and slowly push the top of the water towards the overflow so I get all the oils / protiens on the top of the water going into my sump and allowing my skimmer to work smarter not harder.

 

[CarlaW]

The way I think about ratings is, look at what you need, and then buy 1-2 sizes larger.

 

[nsamouroux]

Ah, good point. With a peninsula tank you won't get much native surface skimming with the overflow at the far side so you would need something at the far end to push all the junk back

 

[roscoe]

All prop-based powerheads are rated as flow, it does not matter the brand.

Since Paul asked me what a K7 is and I told him it was a powerhead by Hydor and his reply was all powerheads are rated by flow. I have looked around and sure enough everyone says flow on prop-based powerheads

Look at it this way a Dart Pump is rated at 3600 GPH output (I believe) that means they have to suck 3600 GPH in to output 3600 gallons so the flow rating is 7200GPH if you wanted to rate a pump as flow.

I don't beleive it at all. He does advocate close loop type systems as what he sell is an equipment that is for closed loop systems. So he can be a lil bias. Also too 3000GPH coming out of a 3/4''-1'' nozzle will of course have a stronger laminar flow vrs. a prop-based such as vortecs, Tunze and koralia as they have a more dispersed flow. If I put my hand directly an inch in front of the MP40 I would feel the same flow as if my hand was 2' away of a dart pump. Prop- based PH has a much much broader flow compared to a dart pump that is pushing water through 3/4''-1'' piping creating more pressure inside the piping and thus shoots water out at a higher velocity thus the reason why it feels stronger. I am positive that the vortec and Tunze is pushing what it is rated for.

 

[Saltyfish]

No, it would still be 3600 GPH. The pump isn't actually sucking, since pumps push, not suck, but being flooded, by 3600 gph of water. That same 3600 gph of water is being pushed out the other side. It's the same 3600 gph of water.

You have to look at what the pump is designed for. A pump in most cases is designed and used to move a certain amount of liquid from one area to another. If 3600GPH goes into the pump then 3600GPH goes out of the pump. so the flow through a pump is 7200GP. Sucking or pushing depends on the type of pump. They have deep well pumps that push from the well and they have pumps that suck from the house incase you can't get electric to the well.

The prop-based powerheads are rated by flow. So if it is rated at 1200 GPH Flow (you can see this on Hydors website) it means they are getting 600 in and 600 out.

 

[nsamouroux]

My plumbing for the sump return / drains is all 1.5", so it should be about the same output apeture as a Koralia Magnum 8, but your point still holds true Roscoe A propeller spinning will create a wider flow pattern than the output of a return pump coming from a length of PVC, which is why I always figured that the sump returns would feel stronger than the powerheads. The guy from OM could just be biased as suggested, but I think there is enough of a reason for me to look into it. It would only end up being the difference between 40x turnover and 55x turnover in my tank if they are indeed rated differently, so it's more curiosity on my part than anything else

 

[nsamouroux]

On the other side of things though Saltyfish, different manufacturers use different terms in their ratings. One powerhead maker might use the term "flow" and mean something completely different from another brand / maker using the same descriptor. Also, there's translation issues to take into account if you want to get picky about it... Tunze is German, Hydor is Italian? I'd imagine their US product packaging translations would just use the generic term "flow" and not even consider the specifics implied by that wording. Still, I think the OM guy brings up a valid point and it's worth looking into, if only because I'm somewhat neurotic and interested in things like this :badgrin:

 

[Saltyfish]

I don't beleive it at all. He does advocate close loop type systems as what he sell is an equipment that is for closed loop systems. So he can be a lil bias. Also too 3000GPH coming out of a 3/4''-1'' nozzle will of course have a stronger laminar flow vrs. a prop-based such as vortecs, Tunze and koralia as they have a more dispersed flow. If I put my hand directly an inch in front of the MP40 I would feel the same flow as if my hand was 2' away of a dart pump. Prop- based PH has a much much broader flow compared to a dart pump that is pushing water through 3/4''-1'' piping creating more pressure inside the piping and thus shoots water out at a higher velocity thus the reason why it feels stronger. I am positive that the vortec and Tunze is pushing what it is rated for.

The nice thing was Paul was not trying to sell me anything. I have all the equipment already to go either way and I have been having issues with the sand if I set the K7's any lower to the sand then what they already are. I have dead spots in some areas including the far end of the tank where the K7's are not reaching (7 1/2 feet away)

If you are looking for a more controlled current in a large tank I suggest you go with a closed loop. Out of the three shops we have here in town I asked all three of them and only 1 said to use powerheads. The other two said to use closed loop. In fact one of them keeps telling me everytime I ask about flow "I would have installed a closed loop" and "you know it is not too late to put a closed loop in" I think I am too the point I am going to follow her advice along with Pauls and put in a closed loop.

 

[CarlaW]

Do you think you can put in a closed loop without having to drill?

 

[roscoe]

The nice thing was Paul was not trying to sell me anything. I have all the equipment already to go either way and I have been having issues with the sand if I set the K7's any lower to the sand then what they already are. I have dead spots in some areas including the far end of the tank where the K7's are not reaching (7 1/2 feet away)

If you are looking for a more controlled current in a large tank I suggest you go with a closed loop. Out of the three shops we have here in town I asked all three of them and only 1 said to use powerheads. The other two said to use closed loop. In fact one of them keeps telling me everytime I ask about flow "I would have installed a closed loop" and "you know it is not too late to put a closed loop in" I think I am too the point I am going to follow her advice along with Pauls and put in a closed loop.

Well I don't have a closed loop and I can tell you that I get crazy massive flow with the vortecs and Tunzes. The two combined would be the best way. I stay away from the closed loop application mainly for cost of operation. You have a pump sucking 300-400w+ 24/7 365 days a year gets expensive. If I didn't have my sump in the garage I would not have to use a Sequence hammerhead for my return but then again that pump will be supplying water to a fuge and maybe a frag tank down the road. I hope you can figure out your flow situation soon. So that way when you set up your 630g tank you don't have to rethink your flow application after it is all set up.