this is just what happened to me last year with my 300.
blanketweed was real bad at the time as well.
what I did was empty the eazy chamber, as normal.
then instead of refilling the eazy chamber from the bottom drain..... I pulled the plunger out from the middle which then reverse flows the water from the outer chamber, this then will pull all the lost k1 and blanketweed up into the eazy.
Does need a few go's to get the lot clear that have got stuck, but will sort it out.
Yes you do Les. The opening to the outer chamber if only slightly larger than the K1 itself. Qua design is is really meant to keep the k1 in the outer ring from getting back into the central chamber and clogging the answer unit that the Nexus was originally designed for. Remember the EASY was an after-thought and came on the scene a few years after the original concept. Once past the the EASY unit the K! will be held in place by the flow and if left long enough might cake together with crud making it even harder to remove.
So tell me, what did you find whan you back-flushed it?
K1.....loads of it, the first time......2nd time a bit more with lots of crud. I now realise why the easy was overflowing...because the K1 was blocking the natural flow......shame EA dont warn you about this, or the need to back flush.
I also think the partial blockage causes dead spots in the filter.
Glad somebody posted the original problem and Jules was on hand.
Problem now solved.
Les
Hi,
If im not mistaken this is the way EA describe the cleaning process of the nexus. Once the centre static chamber has been dumped the next step is to pull the isolation pipe, thus back flushing it....?
I agree with what you say, however there is no actual explanation as to why the central pipe is remevod prior to refilling, and unles you remove whatever has back flushed, it will just go back into the same area again to jam again.
I refil my Nexus with clean water back up to the level before draining, so I know exactly how much water I have lost (160 ltr) and thus maintain pond level.
I now realise why I have been getting the problem with jammed K1.
I cant see anywhere that says this could be a problem if it spills over into the central chamber.
Still all sorted now.
Just rememeber that what goes into that small hole in the central chamber needs to go back into the outside chamber. Had a client who kept dumping it back into the inner chamber only for it not to fluidise.
Jules...when you say fluidise, do you mean that the K1 stays under the water? The reason I ask is that I filled my Easy with the max amount of K1 9as recommended by EA) but find that sometimes if spills over into both the inner and outer chambers of the Easy....is this because there is too much K1? I also find that sometimes when I lift the Nexus lid, the whole Easy rises up and the K1 is stacked.
I also now find that when backflushing, I end up with a handfull of crud encrusted K1 in the central chamber, now surely this cannot be leaking from the outer chamber as the K1 is not the off cut smaller profile and therefore must have got trapped by overflow of the Easy.
Everytime I remove this trapped K1, the flow rate improves immensely.
Les
Casper, when the K1 is new it does float. I'm not sure if your system is pump fed or gravity ... but I have a 200 pump fed and like you during the summer when I back flush the easy I also end up with a handful of crud encrusted K1 in the central transfer chamber. This I just take and throw back into the fluidised outer area.
When I initially setup the nexus it did take a couple of months for the K1 in the Easy to stop floating and sit at water level height and during that time I was constantly having spills of K1 into the central transfer chamber and the inlet vortex.... but as I was fascinated by the filter I simply pushed the K1 in the easy down by hand and recovered the spilled K1. The K1 in the inlet vortex was easy to put back into the Easy but the K1 in the transfer tube generally ended up joining the fluidised K1.
Again, as I’m pump fed with mature media, as the K1 in the easy blocks it floats. I’ve attacked pictures of a completely blocked easy on a pump fed Nexus 200. The gravity fed model once matured does not float in the easy, but as it blocks the outer chamber runs dry.
I agree, but if you have a lid on the Nexus, when it blocks it cant rise, all that happens is that the K1 rises and spills over into either the central tube or the outer easy chamber. The inner wall of the Easy does not rise so the K1 just tumbles over into the central tube.
I am also pump fed. I just wonder if I have too much K1 in the Easy (I used exactly what EA recommended).
What I find is that if you are pump fed and have a bad blanket weed day, you may have to drain and flush the Easy at least twice a day because the pump churns up the weed, it almost becomes a dust and clogs up the K1 EAsily. Is this where it got its name from?
probably .... my Nexus with 110 ltrs K1, 25 ltrs Bio Chips handles between 300 and 500 grams of food a day ... and the blocked picture is after 2 weeks of being on holiday. I also have the full amount of K1 in the Easy..... but don't have and have never had … blanket weed. every year I tempt fate, so I'll probably get it this year ... I put it down to the constant use of Klear, but that's another debate.
ps... you can just about see my lid in the top picture
Ive been looking on the net to day trying to find the best price for a Nexus. Whilst searching on coastal kois site i noticed they have a modification for the nexus range as apparently the new ones have a modification for backwashing- im not that familar with these filters but was just wondering if you had the early filters if this may help??? Have tried to attach link. Sorry if im barking up the wrong tree!
I believe Jules has this exactly right. I had exactly this issue and followed the method that he recommends, fixed it. Material gets clogging the sits at the bottom and by pulling out the tube with the flange that you use during cleaning, you effect a reverse backflush ( at least i think it is reverse . you have to bee sure you don't actually lift the centre column or the K1 will transfer. Good luck!
Gord
Whe I first got my pump fed 200, once I'd finished cleaning it I turned the pump back on and took the stand pipe/bung straight out causing the easy to take in water from the outer chamber and wandered why I was getting K1 floating in the centre pipe. I thought it was from spilling over but kept getting more and more coming. The K1 was coming from the outer
Then I found out I should keep the bung in until the water level in the easy was above that in the outer chamber thus only flowing into the outer chamber and not backwards dragging K1 with it into the centre pipe.
I always make sure my easy K1 doesnt over flow and Ive never had a blockage or loss of flow either.
every year I tempt fate, so I'll probably get it this year ... I put it down to the constant use of Klear, but that's another debate. 
