Ideas on modding MRC Nilsen reactor?

[cr500_af]

Sooooo..... I have an old MRC Nilsen (the stir-stick kind) and the thing is driving me mad. I see why that design is not used anymore... the stick constantly jumps off its little perch, and I have to take the whole thing apart to get it restarted, only to repeat again, anywhere from ten minutes to ten days later.

I am thinking about changing it to a homebrewed version of the newer style (recirc pump to stir the chamber), run on my RKL as a multi-timer so that the ATO won't fill within 30 minutes of a stirring event.

I don't want to go with uni-seals in the sides, just because I don't trust them not to leak. I was thinking about two more JG fittings (large ones) in the top, and feeding the "stir" pump through those... maybe with a tube on the inside of the top, feeding the pump's outlet down toward the floor of the chamber to disturb the kalk slurry.

Anybody see any problems with this plan (calling AndyMan and Grouper!)?

Of course, I'm also interested in knowing if there's a way to make it work the way it was designed to before I mod it... though I doubt if that's doable.

Muchas Gracias!

 

[cr500_af]

No, but it is simply an acrylic tube, with a flat keyholed lid which has two JG fittings in it (inlet and outlet for the ATO pump). One of the JGs has a pipe running about 2/3 of the way down (so that the incoming water is pushed low, and the outgoing water comes from the very top). The floor has a little pedestal thingy for the stir bar, but there are no holes or anything else in the whole reactor.

 

[cr500_af]

No, and that's the problem. It's like spinning a rod on a barstool by magnets from underneath. If it gets the slightest bit off balance or off-center, it gets more and more out of shape until it jumps off of the stool. There is a little "fence" around the "barstool", but it is about 15-20mm larger diameter than the length of the stick. It doesn't seem to have any function other than maybe to lessen the amount that it kicks up the kalk.

 

[cr500_af]

Andy, stand by for pics in about 15 minutes... I'm about to go take the cursed thing out.

 

[cr500_af]

Yep... the center is unoccupied. Do you mean through the floor (as far as the hole is concerned)? Like through the pedestal? Heck, hang on and maybe pics will help.

 

[cr500_af]

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[claudiasmom]

Sorry to hijack this thread but Wow! My floor is clean still!

 

[cr500_af]

ClaudiasMom;528013 wrote: Sorry to hijack this thread but Wow! My floor is clean still!

Of course MY floor is clean...

 

[claudiasmom]

cr500_af;528035 wrote: Of course MY floor is clean...

Hey now, even though I am in NJ/NY area it IS still MY floor!:yes:

 

[cr500_af]

Back on topic:

Andy, I'm trying your idea; my brother is machining the part out of PVC that we discussed.

How high is one supposed to run the kalk "powder level" in the bottom of Nilsen reactors? I have been running it about an inch deep, and when I removed and cleaned it out for this fix, the powder was completely hardened into a crust, which means no more dissolving going on. What's the solution to that, or is breaking that up occasionally part of living with one of these reactors?

 

[cr500_af]

How high above the 2" of powder is your stirring bar? I suspect that mine needs to "disturb" the top a little more to keep it from hardening, so maybe closer to the bar's level will do it.

When I say "completely hardened into a crust" I'm talking about the top 1/16" or so.

 

[cr500_af]

AndyMan;528827 wrote: bar is 5mm from base of stirrer system

So you mean the bar is below the top of the powder?

 

[lilrobb]

The bar has to be in the sludge, at least in my Aquamedic one...