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Is it enough velocity guys?

Hi jolt

jolt100 said:
Smaller holes give lower velocities?? Is this a function of the impeller not being able to overcome the resistance caused by the smaller holes.
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Smaller holes = less velocity from each
Larger holes = more velocity from each

It's about an amount of water going out each hole. Take one big hole which is your hose, then you'll have a lot of velocity from that one. As you spreading your flow on more holes the less the velocity.

All that said is correct if area of all holes equal area of your outflow hose of course.

jolt100 said:
I bought this for the quoted output but is there something i am missing?
Click to expand...

Can't comment on that pump, sorry.

Thanks.
 
foxfish said:
I have never purposely applied that formula..... just experiment until you get what you want!
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Could you give me a numbers of your setup? Size of the hose, spray bar, holes and number of holes? I could again try to work something out with my spraybar. I almost gave up. If I do less holes to achieve desirable velocity then turnover would be even worse. I have APS 1400 in Rio 125 🙁 And what's about backpressure? What's more important? Movement in aquarium or turnover through the filter? Probably there is no really room for compromise, is it?

Mike
 
MikeJojo said:
Clive, thank you for tips. FX5 is still out of my range for now. Do you have any other brand/ model in mind as good or near to FX5? I was thinking of adding Koralia Nano 1600. It's for £27.90 brand new on Amazon. What do you think?
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Well any of the popular brands will do, but to get that flow rate you'll pay similar prices. Like foxfish mentions, just try different combinations to get what you need. It doesn't have to be ideal, it just has to work. The combination of the 1600 plus the single outflow pipe is a good idea too and seems to be the cheapest solution. Try that and see how it goes, then you don't have to mess with drilling holes.

Cheers,
 
I use cheap plastic overflow pipe & drill holes based on a guess, then use different size drill bits & electrical insulation tape to close off or enlarge certain holes etc until it works as I want.. Then once I am happy, I make a final version from my chosen pipe work... if that makes any sense?
However I also use a three speed high wattage pump for my set up (had the same pump for about 20 years or more)
 
Thanks Clive.

Foxfish, I wanted your numbers just to work out what all holes area versus hose area ratio you get. I'd appreciate if you give them to me 🙂
 
[quote="MikeJojo, post: 360582, member: 10926"



Smaller holes = less velocity from each
Larger holes = more velocity from each

It's about an amount of water going out each hole. Take one big hole which is your hose, then you'll have a lot of velocity from that one. As you spreading your flow on more holes the less the velocity.

All that said is correct if area of all holes equal area of your outflow hose of course.


I thought I had seen another thread which said use smaller holes for increased velocities. I will try larger holes, 5mm, as a last resort, at least there won't be many to drill, 64 x 2mm took a while. I've been through 3&4mm already.
Eheim don't quote wattage just output and head. Just assumed the power would be sufficient as its eheim!
Back to the workshop.
Thanks
John
 
I went through 2mm, 3mm, 4mm and gave up on 5mm. Velocity was the best at 5mm holes but not good enough. The last resort for me is to make less holes that it supposed to be... Good luck!

Mike
 
Hi all, just a heads up, I have found that the eheim compact 3000 is my problem. It doesn't have the power to deliver the quoted output through the spraybar. I got a Aquamanta efx600 off eBay and got flow across the tank even when passing through a restricted outlet with my 16/22 atomiser and spraybar.
Just proves you can't trust quoted figures.:crazy:
Unfortunately I also had a problem with one if the hoses coming loose so am just mopping up :arghh:
Hopefully this should help getting the co2 circulating better.
John
 
Hi there

My Koralia 1600 arrived yesterday. Installed it straightaway and improvement in flow is really good. All plants move much more all over the tank. Can't wait and see any better growth now. I will find out in week or two 🙂

Mike
 
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