Waterproof Bearing Brainstorming?

[SkiFletch]

This comes from the vault of things my always-on brain comes up with. Today is/was general maintenance day and while I've got my hands full of calcified maxijet pump from my kalkwasser stirrer/reactor, I got to thinking: "There has to be a better way to stir kalk without constant cleaning of the pump."

The only way I could think of doing that was to remove the heat source (pump) from the equation but still have water stirring. And then I remembered lab-stirrers from my chemistry days. It's easy to make one from a low-speed PC fan and a hard drive magnet, but the problem is noise. A "normal" stirrer just has an encapsulated steel/magnet that rattles around on the bottom of glassware. Makes a racket and would slowly destroy the acrylic bottom of any kalk reactor.

So my next train of thought is could you eliminate the noise/rattle problem by using a bearing? The engineering concept makes sense as I don't need wicked flowrates, just a nice easy stir, so I could encapsulate a magnet and keep it balanced enough. The trick of course is finding a bearing that won't go bye-bye in a kalkwasser solution. Anyone have any brilliant ideas? I thought of a vortech pump, but of course I don't want to be spending that kind of cash. A PC fan with an attached encapsulated magnet would be easy, but probably would just melt to nothing inside the solution. About the only other thing I could think of would be trying to encapsulate and mount some steel to like the shaft of a maxijet or mag-drive impeller and mount that in the skimmer... I could turn down an acrylic plate to fit the ID of the reactor with a little hole in it to accept the shaft as well as mill a top-mount for the shaft. The trick though would be encapsulating balanced steel and attaching it to the impeller. And even then, the mass of the whole thing might not want to spin.

So anybody have any creative thoughts as to how I could rig a bearing that would survive a kalkwasser solution and attach it to some form of impeller/stirrer? Tools and machining skill I have in plenty. Digital readout mill and lathe so I can make just about anything. Enough epoxies and silicones to kill a moose as well as plenty of spare parts and old hard drive magnets. Anybody have any wisecrack ideas?

 

[Conesus_Kid]

Mike, have you checked out the Aquamedic mall reactor? It has a low rpm motor mounted to the top that drives a long, T-shaped mixing rod. This is a different design than youre talking about, but might be easier to implement.

 

[Willistein]

Mike, have you checked out the Aquamedic mall reactor? It has a low rpm motor mounted to the top that drives a long, T-shaped mixing rod. This is a different design than youre talking about, but might be easier to implement.

you can find plastic bearings, and a magnet stirrer would definitely work, but I like the top down approach.

 

[SkiFletch]

Yeah, looked around the net for some top-down stuff, definitely looks MUCH easier. Sometimes I think myself too far down the rabbit hole

 

[tmz]

Magnetic stirrers on calcium hydroxide reactors eliminate that problem.

Personally , I stir by hand with a length of pvc pipe when I refill my brute garbage can once a week or earlier on my 5 gallon bucket . Dosing from a still reservoir with a peristaltic or diaphram pump and timer works great in terms of constancy of dose and simplicity as does a well regulated drip.
It's not just the clogged pump but the more frequent stirring that makes it difficult to get clear water with a steady saturation vis a vie a still reservoir, ime. Of course if the reactor is not sealed airtight , frequent stirring draws in CO2 which depletes the calcium hydroxide via calcium carbonate precipitation.

 

[der_wille_zur_macht]

The (obvious?) issue with top-mounted stirring is that it's harder to have a pressurized reactor, most of the DIY top-mounted stirring reactors are gravity feed to the sump, which of course means it has to be higher than the sump...

But hey, it's a cheap and easy solution. Disco ball motor or microwave turntable motor and a shaft/paddle made from acrylic and you're done.

Like Tom though, I stir mine in "batches" in a large tank that sits still during normal operation.

 

[SkiFletch]

Gravity feed isn't a problem for me, the top of my current reactor is higher than the sump level. I like the thought of a scavenged microwave turntable motor too...

 

[jcw]

Magnetic stirrers on calcium hydroxide reactors eliminate that problem.

Personally , I stir by hand with a length of pvc pipe when I refill my brute garbage can once a week or earlier on my 5 gallon bucket . Dosing from a still reservoir with a peristaltic or diaphram pump and timer works great in terms of constancy of dose and simplicity as does a well regulated drip.
It's not just the clogged pump but the more frequent stirring that makes it difficult to get clear water with a steady saturation vis a vie a still reservoir, ime. Of course if the reactor is not sealed airtight , frequent stirring draws in CO2 which depletes the calcium hydroxide via calcium carbonate precipitation.

Same here. Stir once and forget about it. I think all you are doing is stirring up precipatate into saturated kalk water that won't dissolve anyway, right? I think the manufacturers of kalk stirrers are making money off us reefers again.


I mix mine in a 7 gallon bucket on a shelf above a 5 gallon bucket. There's a bulkhead and valve on the bottom of the 7 gallon that I can open to fill the 5 gallon bucket. the bulkhead has an extension aout 3-4 inches going up into the bucket so I don't siphon the sediment/precipatate off the bottom of the bucket. From the 5 gallon bucket, it is pumped with a BRS pump into the sump.

 

[der_wille_zur_macht]

Same here. Stir once and forget about it. I think all you are doing is stirring up precipatate into saturated kalk water that won't dissolve anyway, right? I think the manufacturers of kalk stirrers are making money off us reefers again.

The idea behind a "reactor" for kalk is that you are able to hold a LOT of powder in it. Then, you pump fresh, new RO/DI into it at some desired dosing rate. The water is mixed with the stored powder as it's pumped in, and saturated kalk comes out the other end. It's a totally different approach to mixing fixed volumes at a preset interval, you're essentially constantly mixing a stored volume of powder with new water on an as-needed basis.

If you have a basement to keep a big Brute in, it doesn't make much sense to have a reactor IMHO. But if you have to keep everything under a small stand, they're pretty much the only solution that doesn't require a lot of manual work.

 

[Willistein]

If you have the room, I like the idea of a large amount made up and dosed instead of the reactor. I just hooked up something like this. I had a peristaltic pump on hand and hooked it up to a digital timer. It doses 8 times a day for 1 minute. I measured the output at about 200mL per minute. I'll see if it needs more than that because I'd like to do all of my topoff with kalk.

In addition, I have a separate freshwater topoff that runs on a float switch. I need to add a high level float switch to shut off both the fresh water topoff and the kalk pump in case either one gets stuck on for some reason.

 

[SkiFletch]

Yeah, for me with a 2nd-floor tank, it's all about space. Not to mention, mixing caustic substances in living spaces isn't exactly the smartest thing to do . So dumping a bunch of powder in a container, closing the lid and forgetting about it are things that appeal to me.

 

[jcw]

The idea behind a "reactor" for kalk is that you are able to hold a LOT of powder in it. Then, you pump fresh, new RO/DI into it at some desired dosing rate. The water is mixed with the stored powder as it's pumped in, and saturated kalk comes out the other end. It's a totally different approach to mixing fixed volumes at a preset interval, you're essentially constantly mixing a stored volume of powder with new water on an as-needed basis.

whoops. sorry. thanks for the clarification.

 

[tmz]

Space can be an issue . On a 65 g tak you'd need a five gallon reservoir to go abut 5 days without refilling. A Neilsen type reactor ,ie one that holds undissolved kalk and is stirred as new water enters can work. Needs to be sealed well or CO2 entering the stirred water will deplete the kalk leaving what is essentialy aragonite sand. Timing of the stirring and dosing should be such that the water settles out before actual dosing and only clear water is dosed to avoid dosing impurities and undissolved kalk. The later can lead to; an overdose, a ph spike and precipitation.