Page 4 of 4

Re: Nexus 300 probs

Posted: Sun Nov 09, 2008 8:11 pm
by Jules
EA quote 13,000 ltr per hour flow through the filters. your pump pulls (alledgedly) 15,000 ltr per hour hence the 2,000 difference. The swept bends will not increase flow but will still retstrict the flow back to the pond, however they are less restrictive than kncuckle bends.
Is there any where else you could pull from? Skimmer, side wall feed?

Hope this helps?

Jules

Re: Nexus 300 probs

Posted: Sun Nov 09, 2008 8:16 pm
by Michaelb
is there a calculation for working out the loss of flow ?

Re: Nexus 300 probs

Posted: Sun Nov 09, 2008 8:31 pm
by Jules
I normaly use 2.5% for swept 2" 90's. I will double check this tomorrow and post.

Jules

Re: Nexus 300 probs

Posted: Mon Nov 10, 2008 9:34 am
by jez
after reading the installation guide it says the 300 flow rate is 15000 litres per hour but the EA page shows 13000??

so I guess your pump should be ok.

Is the isolation valve from the pond fully open to the 300? It could be a restriction after all as if the supply was free flowing i would still expect the easy part to stay around full but the bio to drop if the pump was too big as a 4" inlet can supply about 14000 litres ish I think.

This is an interesting one!

Oh and this is fairly in depth but interesting regarding flow rates through pipes ( American based )[url]http://www.koiphen.com/members/harveythekoi/plumbing.pdf[/url]

Re: Nexus 300 probs

Posted: Mon Nov 10, 2008 8:43 pm
by koimod
I got given this link to try and help , it is a work in progress but seems to work ok.

http://pumpcalc.evolutionaqua.com" onclick="window.open(this.href);return false;

Re: Nexus 300 probs

Posted: Tue Nov 11, 2008 8:22 pm
by koicarpus
Hi,

I have exactly the same head loss in my Eazy 300. My nexus is brand new and has a 4 foot vortex in front of it.
I was lucky to have guessed the head loss in both and have set them up at a certain height to work OK.
The top of my nexus is roughly 4 inches below the water level. the vortex is roughly 1 inch below water level.
I'm pulling roughly 3200g an hour with a brand new espa pump.
I also have a 24" beadmaster after the nexus, and my water quality in the 6000g pond couldn't be better!!
I know we're on the border-line with the recommended flow of the 300, but I really wanted to turn the pond over in 2 hours, as I have alot of trees around the pond, hence the stupid amount of filtration I have.
The only problem I have is that if I turn the pump off everything overflows, so I have to concentrate when cleaning the filters, otherwise I get wet feet. Apart from that I couldn't be happier!!

Kind Regards

Dave

Re: Nexus 300 probs

Posted: Tue Nov 11, 2008 10:32 pm
by Jules
Dave what happens with you rlevels when there is a power cut and water equalises? Does it flow over the filters and does the K1 go every where? Have you not tested/thought about this? Just an thought.

Jules

Re: Nexus 300 probs

Posted: Tue Nov 11, 2008 10:46 pm
by koicarpus
Hi Jules,

yes I have thought of this, and to be honest I've lived in my house for 5 years and touch wood, have not had a power cut yet.
I know it will happen one day, but I like living on the edge, and I know it won't be funny when it happens.
I think the only thing mike can do is reduce his flow or lower is nexus.
3000+ gallons an hour is alot of water for a 4" pipe to feed under gravity, you've got to accept quite a lot of head loss with this kind of flow which we both have going through our nexus.
My set up is very like mikes, but my nexus is a lot lower.

Kind regards

Dave