Loaches Online Forum

If you would like to dramatically increase the flow of the venerable old AquaClear 70 powerhead (formerly 802) then read on.


I’ve only been a member here for a short time but reading the threads and articles about the River Tank began to appeal to my tinkering DIY mentality and I knew I had to build one. The theme that seemed to repeat itself in the information I read was the importance of achieving maximum water flow and not to skimp on the output of the power heads.
I began assembling parts and before long had everything assembled for a test run.



I used Beckett pond pump prefilters


The beautiful thing about AquaClear power filters is that intake tube is a perfect fit into standard ¾” PVC pipe making it easy to plumb into the manifold for added directional flow.



I had an old Otto power head and bought a new AquaClear to go with it.


Here’s the setup ready to fill and test.

I filled the tank and plugged in the pumps and was immediately impressed with the output from the old Otto pump unfortunately I was very unimpressed with the comparatively anemic output from the new AquaClear.
To be fair, the Otto is rated at 500 GPH vs. the AquaClears 400 GPH.\


After a quick inspection I realized the majority of the problem was the intake grate was blocking approximately 70% of the intake flow area.



I also noted that the plate designed to control flow levels was a major restriction to the impeller even when in the full open position.


So far everything appeared to be an easy fix but a test rig was in order to prove out the success or failures of my ideas. I came up with a simple idea to do a timed draining of a five gallon bucket.


To start with I timed the pump with no modifications. It was a fairly anemic 96 seconds. That comes out be 187.5 GPH.




First on the agenda was to remove that ugly grill. Time to pump 5 gallons, 78 seconds! 230 GPH. Thats an improvment but we can do better.



Next was to throw out the adjuster plate and carve away some of the plastic blocking flow to the impeller
Time to pump 5 gallons, 68 seconds!! 264 GPH. I didn't do the math but thats a healthy improvement and the best part is that its free!


You can see here that the water has a clear shot at the impeller now.



Now I know some of you are saying “hey, were still way under the 400 rated GPH” but keep in mind that the copper drain tubing slips inside the output orifice and causes a slight restriction. Also note that as the bucket drains down there is over a foot of head to overcome not to mention three 90 degree bends in the copper tubing. Wthout the tubing and just shooting it over the side of the bucket I was able to empty the bucket in about 50 seconds. Thats 360 GPH and now almost feels as strong as the Otto!


To really see the dramatic increase check out this side by side comparison of one that’s modified and one straight out of the box. You can see the close one puts up a little arc of water but the far one is splashing it clear up to the lights.


My next tank will be a 75 gallon using 3 modified powerheads and a AquaClear 110 power filter all plumbed through 4 prefilters. That should keep the Hillstreams happy

Nice bit of DIY

I have made minor modifications to a couple of my powerheads in the past and the difference in flow rate can be amazing, keep up the good work

But wait... its supposed to pump 400gph without the mods...

Oh well, from now on, I'm getting otto powerheads.

I do like the aquaclear hang-on filters as the one I have keeps water crystal clear on my 10 gallon tank.

That's very interesting and also very logical. I like a bit of tuning

One thing you need to watch out for though is debris making its way through the sponges and getting into the powerheads. I've had snails in my tanks in the past and babies used to migrate through the sponge and end up jammed against the strainer you've removed. These would severely reduce flow, but without the strainer would have been hitting the impeller. Plant debris can make it through too so I would advise quite frequent cleaning of your sponges once the system is up and running.

I would also seal up the yellow lever's operational slot in the body of the pump so small fish or debris could not be ingested.

Martin.

Martin,

I've been wondering. Would it be optimal to have powerheads of the same strength on a manifold or is it ok to have a slight difference in water movement rate? I'm asking this because my current powerheads are dissimilar in flow rates and pending an upgrade, may remain like that for a bit.

(still working on my tank space, will post pics soon )

KKF,
You've got the 3 intake pipe(s) 'T'ed together at the end near pumps. Does the higher sucking strength of the powerheads affect the intake/flow-rates of the external filter unit? Is it having to work harder then it should to get water away from the powerheads, and have you tried without the 'T's?
A

Optimal yes, but not a necessity. Because the tubes are all connected water can balance itself out depending on where the suction is.

One thing that must be remembered with using powerheads in this application is that ultimate flow is limited by the internal diameter of the tubing. You can only add more powerful pumps up to a certain point where it has diminishing returns. As killforfood states, the 90 degree bends cause flow restriction. I note that in his manifold he has swept 90 bends rather than the more compact 90 degree fitting. These will reduce flow restriction due to internal turbulence and are great if you have the extra room available. Any straight 90 or T-piece will be a bit restrictive.

Martin.

got two of those myself!

Martin,
I also used thin wall pipe. It's about half the wall thickness of the standard schedule 40 stuff. I think they call it class 200 or something? There's really no structural reason to go with the heavier stuff and a slight increase in ID gives an exponential increase in cross section. Somebody help me here, I don't remember the math.

Interesting. I'll look for swept joints. I do have the room in the tank I'll be setting up.

Thank you

Why not heat-flex electrical conduit? Small wall-thickness and comes in several diameters. You heat it up and bend it to the contours of what you want- no joints, PVC/tanjit headachs or hard corners. Can't get it here....

Not sure that electrical conduit is potable water safe like the plumbing stuff Andy. Generally this stuff works adequately in most applications.

Martin.

andyroo wrote:KKF,
You've got the 3 intake pipe(s) 'T'ed together at the end near pumps. Does the higher sucking strength of the powerheads affect the intake/flow-rates of the external filter unit? Is it having to work harder then it should to get water away from the powerheads, and have you tried without the 'T's?
A

Andyroo,
I was wondering the same thing and turned off the two powerheads while the filter was running and didn't see any obvious increase in water flow.There has to be some slight effect though because the suction of the powerheads pulls a vacuum on the entire manifold. The 4 way fittings need to stay just to hold things together, also they allow more tubes to fit in the narrow tank but if I thought it was needed (I don't) I could plug or isolate the filter from the rest of the manifold.

This tank is an old scratched up freebie really just for practice.
Check out my poor mans trailer trash lighting.

In a week or so I'm picking up a new 75 gallon and already have the manifold built for it. It's the same basic design as this one except I've increased the number of tubes to four. The filter I'll be using is an AquaClear 110 (formerly 500). Its rated output is 500 GPH. It's to be seen whether or not this will cause conflicts whilst (I just had to use the English version of "while" so under used in America. Much nicer ring to it ) fighting against 3 powerheads on the same manifold.
This old 55 gallon will probably end up being my Qtank for the much anticipated days when I can start buying fish!

I modded one in a similar fashion, plus I very slightly increased the diameter of the hole in the centre of the red part and radiused it's intake side. I put a slight radius onto the inlet side of the outlet pipe to hopefully give a slight ease in flow out of the impeller housing..

The really interesting thing was I did a straight out of the tank test and improved on that flow by 50% just by cleaning all the components.

I've added back in the yellow part, but opened it up like you did the black housing. There's a straight shot into the impeller now plus the yellow lever slot is covered properly. Left open, I reckon plant debris and stuff will get sucked in there.

Most noticeable difference is that it really buffets the hand when placed in front of it compared to the stock configuration.

Best flow (approximate) I got was 900 LPH which is WAY below the manufacturer's claimed 1540 LPH.

Martin.