Advice please - Nexus 300

[TicToc]

Group,

Can you advise on the following please. Currently there are several Nexus 300's being sold second hand on the net. Clearly everyone has a slightly differing set up and not everyone uses this particular product for various reasons and I would appreciate some guidance on the pros and cons of a Nexus 300/200. I have read the K1 thread which inspired us to seek a little more advice.

By way of background, we are currently at the planning stages of a pond rebuild (est 7,000 gals). I am considering buying a second hand Nexus 300 and have read/listened to various comment about using the Nexus. Some say it is not all its cracked up to be and will need various modifications once you have bought one, others say its the business and doesn't need mucking about with.

I therefore have several questions and would really appreciate any guidance/help addressing.

1. If you buy a second hand Nexus, which will be at the very least a few years old. Has the design changed at all or does it remain the same sized non revised model?
2. If it has changed a little are there any weaknesses ccurrent users have spotted or to watch out for with old ones? Does the latest version better predessors?
3. Some say a vortex should be incorporated pre Nexus whilst others say after and then through the filters, I imagine this will make a difference but what is considered the better overall option?
4. One chap suggested I need 2 x Nexus 300 for this sized pond + large vortex, nothing else! Admittedly, he thought I was a Village idiot from planet Zanuessi and funnily enough he remained in selling transmit mode for sometime... But I am now starting to lose my way with some of the conflicting advice I have sought. Is the concept of having two Nexus 300 a practical solution? Even if it could be afforded surely a filter is needed.

Thank in advance for any advice.
Regards,
TicToc

[DidIdothat]

Your problem is that 7'000 gallons is just near the top end for a 300 and so 2 300s would be good. I run a 300 on 3500 gal and I am well chufed. You still need to think about how clear you want the water and is the clarity for you or the fish.
Koi love green water and this has very little to do with filter, green is just something you can't just remove with a filter. It's just unfortunate that we like it Gin clear so we can see them.
I also run a home made easy with about 4 times the capacity of the 300 which is fantastic but not quite as easy to flush and thats where the cost is.

I my opinion, if you can afford it and want great water use 2 x 300s, if you want to scrimp go for 1, it will work once matured.

Phil

[gingeletiss]

I therefore have several questions and would really appreciate any guidance/help addressing.

3. Some say a vortex should be incorporated pre Nexus whilst others say after and then through the filters, I imagine this will make a difference but what is considered the better overall option?

4. One chap suggested I need 2 x Nexus 300 for this sized pond + large vortex, nothing else! Admittedly, he thought I was a Village idiot from planet Zanuessi and funnily enough he remained in selling transmit mode for sometime... But I am now starting to lose my way with some of the conflicting advice I have sought. Is the concept of having two Nexus 300 a practical solution? Even if it could be afforded surely a filter is needed.

To answer 3.....everyone will have a different solution. At the moment, I have a big blue filled with black knight brushes, as my pre-filter, but I'm in the process of converting my old 4 bay, and will be using that in front of my Nexus.

As to 4.......I agree, you will need 2 Nexus, or a combination of a Nexus, and some other filter. I run mine on 3000 gallons plus filters.

[TicToc]

Thanks for your advice Dave and Phil. I have emailed Nexus on the other points to see what modifications may have been revised but heard nothing back just yet.
Cheers
TicToc

[koimod]

To Question 1 - Nexus manufactured after March 2006 are different. The capacity of media for the outer (moving bed) area has been made larger so as can fit 300 litres of K1 against the recommended 200 litres on the earlier model.

An easy way to work out the difference - at the top of the inlet on the newer model there is a piece of plastic (shaped like a D) screwed in above.

[Gazza]

Hi Tic Toc,

The one thing you need to remember is big ponds take a lot of looking after in time and also in water/gas/electricity so make sure you sit down and have a good look as with the rises they say are coming its going to make a big difference to us koi nerds

Are you going to heat and if so how gas or electric this also makes a big difference while electric is easy to install gas is normally cheaper to run

OK thats the sensible stuff out the way now back to koi A 7000gln pond is a big pond and i would defiantly go with two sets of bottom drains and filtration and if you can get them in then Nexus is the way to go or even perhaps one Nexus and one bead filter but make sure its the one that doesn't need a big pump.Then i would also have another filtration on the skimmer perhaps a shower or a large TT which either way i would personally have BHM in.

Are you going to have a filter house or shed so you can do all the plumbing and mount the pumps and stuff

please keep us in the loop as we love seeing these come out the ground

[TicToc]

Many thanks to Koimod and Gazza for knowledge and advice.

Current thinking:
I will be building a filter type housing below ground with two foot or so of this ceiling above ground (concrete roof). It is currently a blank canvass. Paper plan looks like it will be 2 x gravity fee Nexus 300, large filter - brushes and japmat (probably pre nexus). Not sure about vortex acquisition or location yet. Lacron sand filter is the last of the primary system. Secondary system is skimmer, UV and gas heating (though probably used only in exceptional circumstances).

Two aerated sump drains (benched circa 6ft) feeding through to a first chamber which I hope to also use as a disposal chamber. Once of the planning board I will take and post piccies.
Regards,
Tictoc

[herbie]

TicToc

I use 1 Nexus 200 on my pond run fron a side feed as well as a 3 bay normal filter.

I'm thinking of getting a Cetus Seive to put in before the Nexus.

I've got to restock 1st.

But If you can you could put a Seive in on a least 1 of you're setups

They collect a lot of crap from apparently clean water.

Regards

[TicToc]

Now I hadn't thought about a sieve, never mind Cetus! Assume you have seen this particualr one in operation and are particulary impressed....... I'll add into my list. Good luck and let me know how you get on with it.

Regards, TicToc

[Gazza]

Hi Tic Toc

I think most say that you don't need anything before the Nexus as long as you get the Easy bit in the middle which is the mechanical part which is static K1.You could have two of them and then the skimmer you could have the other filter which should help polish the water and this will also make the maintenance easier as you will only have to clean the Nexus as cleaning brushes is not a very nice job.

[TicToc]

Thanks Gazza, will forward a grovelling PM once its all down on paper for your perusal if you can spare a mo. Cleaning brushes is presently 2+hr job every other week at present I dream of lower maintenance on V2.
TicToc

[Gazza]

Hi Tic Toc,

Yes those brushes are a pain especially when its raining and cold The other good thing about the static K1 is once you have done it your maintenance will be some much easier you will keep on top of it more often and in doing so end up with a cleaner system,the fish will love it

[TicToc]

Gazza,
I was being a little conservative about the two hours if I'm honest. Its nearer 4hrs and a bad back cleaning them through bending over a soil pipe manhole.
Many thanks TicToc

[Davej]

Hi TicToc

I run a pair of Nexus 200 on 6000 gallons, now supplemented with a Bakki which runs from one Nexus and a Skimmer.

At 7000 a pair of three 300 would be ideal.

Putting anything in front of the Nexus is not necessary. If anything it is worth putting something after the Nexus to polish the water, particularly if you run the flow at a reasonable rate, I have Waterco Cartridge filters on the returns that I have converted to take foam inserts, most of the time I don't need to stick a foam in but if I want that final gleam then it is there if I want it.

Takes ten mins to clean the filters and most of that time is spent drinking a cup of Tea and testing the water parameters whilst they boil.

Regards

Dave

[TicToc]

Dave,

Apologies for delay many thanks for advice. Have now purchased 2 x Nexus 300. Wow theses are big chaps Bigger han I imagined.
The picture you paint of tea drinking and testing sounds fab. I can't wait to get cracking in Autumn.
Cheers, TicToc