Improved Jobo CPE 2

One gripe that I've always had with the Jobo CPE 2 is that there is no circulation in the water bath. This means that while the water immediately surrounding the heating element and sensor warms up very quickly, the rest of the bath remains barely changed. You can try to stir the water around by hand to keep it even but that is inconvenient and ineffective especially with all the bottles and graduates in place. My solution was to mount a small aquarium water pump to one end of the unit where it pulls in the water and then sends it to the other end of the water bath via a flexible tube. The water has to to circulate back past all the chemical bottles and the heating element, keeping the temperature even throughout the entire bath. Now, with the pump running I can stick a thermometer anywhere in the bath, including in among the bottles and get the same reading. This brings all of my chemistry up or (in the Summer) down to temperature evenly. It works great and if you slapped a logo sticker on it, you would think that it is an expensive Jobo accessory. Here's a couple of pix (there was a url link here which no longer exists) . If the link doesn't work, they are in the non-gallery

That's a great idea, as my solution was to mount a drum and have that rotate for about 5 minutes and that movement waas enough to move the water around, but your solution will be qucker. The other benfit is to use the pump to empty the beast. Put a piece of tubing over the end and voila, auto emptying. Way better that trying to pick the beast up and pour the water out.

Flotsam, you get the star of the month award

Mike

Thanks for the star but it was a pretty obvious solution to a problem that bothered the heck out of me ever since I got that CPE. I don't know why JOBO never bothered to deal with it. It is a dream having the water bath perfectly even from end to end and all of the solutions come up to the exact same temperature without any attention from me at all. I just figured others might be interested.

I've never tried using the pump to empty the processor although it would be pretty quick. I just use a small hose to siphon off most of the water and then dump the rest.

-Neal

Thanks Neal!

The funny thing is, I have an aquarium pump in my darkroom sink that I use to curculate print wash water, but I never thought to use it for the Jobo.

Frank

Hi. I understand this is a rather old thread, but I would like more information on attaining the pump. I'm not an expert on aquarium equipment, but I am not familiar with the one seen in the photo. I'll probably drop by Petco or any aquarium store tomorrow to see what they have, but it would be nice to know which one specifically to get.

How about pump capacity?

Thanks for any help.

I'm not an aquarium buff either. I bought that pump years ago for another photographic project. As you can see from the picture, my pump expells the water out through a tube. I can run it down to the other end of the CPE so that it can circulate back past the heating element and solution bottles. The new pumps that I have seen all seem to dump the water back into the tank like a waterfall. You might have to look around a bit to find one that is suitable.

As far as volume. All you are trying to do is move water around. I think that anything for a small aquarium would work fine.

absolute pure genius

I've been using it for almost a year and it works like a dream. A huge improvement.

I have a CPA2 with a built in circulating pump which operates independantly from the drum motor.
Perhaps Jobo makes an adaptor kit to retro fit, its worth asking

I know this is an old thread, but I was thinking about trying this pump thing out. do you still have the pics? I couldn't find them. I also found a water chiller called "IceProbe" for under $200.

I could use some guidance here. My tap water is 75 degrees in the summer. Not kool!

Thanks,

Dorothy

I use a small 'water feature' pump bought from a garden supplier. Used in exactly the same way works a treat. Cost AU$15.
I do find that the depth to which one fills the CPE-2 affects the set temperature.
Is there a filling mark that I have missed?

Pete, the filling mark is when you have enough water to cover the bottom of whatever tank you are using, with the solution bottles in place.

I think you will find that the temperature will stabilise to it's intended accuracy within one hour. This is providing that you also have the solution bottles in place and full of solutions.

I would assume that with a water circulation method employed, you could halve the one hour stabilisation time, but I wouldn't be 100% sure about that.

When I was doing a very large batch of E6 many years ago, I got my father in-law to switch the CPE2 on about two hours before I came home. The temperature was always perfect, every evening for four weeks I developed four rolls of E6.

My late father in-law, who served in the German army as a photographer, couldn't believe the consistant quality I obtained. He went back to Germany with some of his best ever, holiday slides.
Mick.

Hi !
I've used the add on pump on the CPE2. It doesn't speed up the process but even out the temp from the first left bottle to the last right graduate.
The pump is a really cheap aquarium one, inmmersed under the electronic box, and pushing water into a tube whose exit is at the right hand end of the bottle rack.
I advise you not to over flow the CPE2. When filling, put enough water for the processing drum to be into the water WITHOUT floating. If you put too much water, the right end of the tank will be higher than the left one, causing the right hand end of the film/paper to be out of the chemistry... And you'll waste products and time ! Been there, done that....
Hope this helps !

Interesting points about filling levels. I have two white lines on mine. The top one is about an inch above the lower. Presumably each is the correct water level for different types of drum.

Can anyone say which drums correlate with which line.

Thanks

pentaxuser

Here you go Dorothy.
I couldn't find the files on my computer but it took me about a minute to put my hands on the negs