View Full Version : DIY Nilsen Reactor project

06-07-2004, 09:22 AM
Okay, I'm getting ready to build a Nilsen kalk reactor and need some input. I have 4 1/2" o.d. acrylic tubing which I plan to use with pvc fittings. This will not have a magnetic stirrer, but a pump to stir the kalk.


1. Some plans show the fittings threaded into the body and some show them glued in. Is one better than the other?

2. I've read that I should use Weld-on 4052, or 40, or 42 to attach acrylic to pvc. I attached a pvc fitting to a scrap of acrylic with Weld-on 16 and it seems to make a good bond. Is it okay to use 16, or will I have a problem in the long run?

3. Finally, dosing. If I use Spectrapure's single liquid level controller I estimate it will add about a gallon of kalk at one time. This seems like too much in a 90 gallon tank??? Would I be better off to use a peristaltic pump? Can you run a peristaltic pump on a timer? I'd rather dose only at night.

Sorry so many questions. All replies appreciated. :cool:

I'll post pics of the construction, but it'll probably be a couple weeks--busy social life :rolleyes:

06-07-2004, 09:33 AM
I glued my fittings into the body of the reactor. I feel better about the seal, as opposed to threaded. This is just where you are comfortable with your DIY skills. If you are good with a tap and dye set then you should be just fine with the threaded.

I ended up using weldon 16 and it was fine, but I'll let the experts here answer that for you.

I would definetly recommend a peristaltic pump. My kalk topoff runs 24/7 without any issues and I evaporate a little over a gallon a day on my 75. It's your call as to weather to run it only at night or all the time.

06-07-2004, 09:47 AM
Weld-on 40 would work for PVC to Acrylic.


big t
06-07-2004, 10:30 AM
I also vote for weld on 40

06-07-2004, 10:43 AM
The experts have spoken. I would do what they say as they have plenty of experience with acrylic.

06-07-2004, 01:55 PM
Thanks everyone. Sounds like the Weld-on 40 is the adhesive to use.

Any input on the dosing method/equipment?

TIA :)

06-08-2004, 04:04 AM
Weldon 16 works and mine has not leaked since day one, plus it's cheaper than 40.

I have our topoff on a float switch, that turns on a PH from the ro/di tank through the kalk reactor and to the sump. On the kalk ractor (diy) there is a PH that is on a timer that comes on every 6hrs for about 5mins - didn't want to spend $20 on a digital timer-that mixes the kalk. Nothing fancy- but it works.


06-08-2004, 04:46 PM
Thanks wanareef

I'm trying to find a 1/4" pipe tap. The 1/4" tap at the local hardware is 1/4-20 and I believe pipe thread is 1/4-18. Can anyone confirm that and suggest a place to buy such a critter?

I found one online, but they had a $25 minimum order--the tap was only $5

FWIW-- I'm going to tap my threads into a pvc plug. So if I screw it up I can just try again and the body of the reactor won't be ruined.

06-08-2004, 07:21 PM
Yes a 1/4"pipe tap is 18 threads per inch it also is made on a taper for sealing purposes

06-08-2004, 11:53 PM
You might try harborfreight.com. They have a complete set of pipe taps up to 1.25", for not too much. I use them a ton now.


06-09-2004, 02:20 AM
As Zeph suggested, harbor frieght is a great place. That 1/4-20 is a "regular" thread size and would be "straight" and not tappered. Kind of confusing.

06-17-2004, 09:23 AM
I have it partially assembled. This is a pic of it -- not glued yet and still don't have the fittings for the water in/kalk out yet. The fittings on the collar are for the mixing pump which will be a Eheim 1048.

06-17-2004, 09:25 AM
Oops, didn't realize that pic was so big--can I fix that?

06-17-2004, 09:43 AM
Can I glue schedule 40 to schedule 80?

06-17-2004, 09:46 AM
I actually remembered to take some pics during construction, so I'll post a few.

I drilled two 13/16" holes in the slip coupling 90 degrees apart using a wood boring bit, then cleaned up the hole with a sanding barrel on a dremel

I clamped the coupling to my workbench so it would be nice and steady.

06-17-2004, 09:48 AM
That size bit will give a pretty snug fit for a 1/2" pipe if you're very careful to drill straight

06-17-2004, 09:54 AM
The pic doesn't show it very well, but I used the dremel to cup the edges of the fitting to fit the outer contour of the coupling.

I want to use John Guest fittings for the water in/kalk out and I have a 1/4" pipe tap, but I can't find a tap handle large enough to hold it (if it's not one thing, it's another :( )

Sooo...I noticed US Plastics has 1/4" schedule 40 fittings and thought I'd just use a reducer for 1/2" to 1/4".

06-17-2004, 06:29 PM
looks good

06-25-2004, 12:24 AM
Why not get a tap handell for your tap? The JG fittings are mighty handy. I'm sure that you could get a tap handell from home depot or harber freight. Just a thought.

06-25-2004, 12:25 AM
Handle.... I suck at spelling. Sorry!

06-25-2004, 09:03 AM
Blane, I discovered that pipe thread taps are pretty big and the right size handle is hard to find; however, since they are tapered and the pvc cuts easy, I was able to use the tap successfully with a crescent wrench.

The JG fittings are great!!!

As I stated in another post, I would highly recommend tapping into the pvc rather than slipping the pipe through a drilled hole. Even though I used a coupling to add stability, it is definitely the weakest spot and I broke the seal when I put the hose on.

Got that fixed and filled it last night and set the mixing timer. Should be ready to start dripping tonight.

I'm using an Eheim 1048 as a mixing pump. Kind of pricey, but I really don't like the idea of using a maxijet externally. I expect the Eheim to last a very long time and to never leak.

06-25-2004, 06:20 PM
I wasn't aware that the tap handels were so hard to find, sorry. Do you have any good pics of your reactor? If so, I'd love to see em. Happy building.


06-25-2004, 06:59 PM
Yeah... um, yeah. There's pics on the thread... yeah. Dont mind me or my mindless posts.

Hmmmmm.... yeah. I'll just go shove my head back in the sand now.