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Pond gravity fed system (11 posts / 1,101 views)
carpyclarkey carpyclarkey
Posts: 1,901
Post #1 28 Jan 2022 08:17
0
Hopefully ok in the carp section as it's carp in my pond!

Has anyone got a calculation for a pump size on a gravity fed system? The ponds 4100 lts and has a medium stock of carp.

I've got a 4 bay filter and am installing a bottom drain with 3 inch pipe to keep the velocity high. From what I've seen a 5000 sized dry return pump would be fine
Jamesvg Jamesvg
Posts: 1,165
Post #2 28 Jan 2022 09:26
0
In reply to Post #1
You could always get a 10,000 variable pump, will allow you to run between hourly and 2 hourly turn over rates depending on season/if you find settlement in the drain.
Good idea to build in purge capability for the drain too so that you can flush out any debri.
carpyclarkey carpyclarkey
Posts: 1,901
Post #3 28 Jan 2022 10:19
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In reply to Post #2
Thanks mate, all good points especially the purge points. Heard a few issues with people having bacteria issues from silt build up in the bottom drain pipes
Old-Cornishman
Posts: 688
Post #4 28 Jan 2022 10:38
0
In reply to Post #1
Something else to consider if you have the room is to install two pumps, one for summer and a smaller one for winter. That gives you the option of running both to give extra flow or a backup for a few days if your main pump fails. Sods law says that when your pump fails the one you need will be out of stock or your supplier will be closed for the weekend.
If you can turn your pond volume over in an hour you should be fine, obviously much less needed in winter.
When you size your UV lamp go bigger than they say in the spec.
Mart74 Mart74
Posts: 3,509
Post #5 28 Jan 2022 10:44
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Lots of variables on this one. I used to run a 7500lt with a four inch drain through a multibay with a 5500lt pump.

It used to be good practice to turn the pond over once and hour, some go for twice or more per hour.

I'd always advise going for a larger pump and slowing it down if needed using a ball valve along the pipework. Also remember the pump is only ever going to get slower in time from wearing out and build up of debris in the pipework.

It might be worth checking the amount of flow your filter can handle, it's usually that which determines the pump size.

Definitely have some way of perging the drain. I used to use the vortex on the filter, it's amazing how much it would drag through even after a couple of perges. I'd do it once a week at least.
Doing_a_brew Doing_a_brew
Posts: 3,035
Post #6 28 Jan 2022 10:57
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In reply to Post #1
Some tips for the filter, if you're feeding a bottom drain directly into the multibay then you need to be really hot on the maintenance as a massive amount of sludge will build up.

I ended up fitted a gravity fed sieve (great bits of kit) then pump fed to a multi bay with only matting cartridges that could be lifted out to make it totally empty and visibly spotless. Any traditional multi bay media (alfagrog, plastic tubes, brushes etc) will just hold waste and never get properly clean. Been there done it, more than once!

carpyclarkey carpyclarkey
Posts: 1,901
Post #7 28 Jan 2022 11:11
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In reply to Post #6
Cheers guys, does a gravity fed sleeve then use a submersible pump to feed the multi bay?
Frenzy Frenzy
Posts: 11,403
Post #8 29 Jan 2022 10:00
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In reply to Post #1
i run 2 x vari pumps that feed the Profidrum filter system via 2 4 inch bottom drain and 3 returns.
Bigcarpchaser Bigcarpchaser
Posts: 159
Post #9 4 Feb 2022 22:15
0
In reply to Post #7
Gravity systems have pumps after the filters, pumped systems before.
Water will always find level so gravity aystens at same level as top of pond. Pumped systems above
If anyone is considering building a big pond in the near future I'm flogging all my stuff due to health reasons, drum, shower, moving beds, pumps etc. if interested I'll post in the for sale section.
Frenzy Frenzy
Posts: 11,403
Post #10 5 Feb 2022 10:13
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In reply to Post #9
shame your having to give it up mate
Doing_a_brew Doing_a_brew
Posts: 3,035
Post #11 5 Feb 2022 17:59
0
In reply to Post #7
Yes, the only downside being if you want the multi bay under decking etc as it would need to be higher than the pond to gravity return.
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