Pumps - need and expert for help

[adifferenttank]

Please pardon my ignorance on the subject of fish tank pumps. I hope this posting will find the experts who can help me. I am looking, I think, for an aquarium pump, but what I am looking for isn't for an aquarium though. What I want to use is a pump to fill and empty photo processing tanks - kinda large - 3 1/2 gallon size. Aquarium pumps came to mind. But there seem to be many available of widely differing capacity. I don't know what to specify. I can describe some of my needs though.

I don't want it to be so powerful as to have a jet of solution blast off the floor and walls of the tank and splash everywhere, but don't want to take ten minutes to empty a tank either. I am guessing that a fill time from two to four minutes would work well.

Use will be for black and white photo processing solutions. Nothing nasty - intermittent contact with hands in the solutions is not a problem - but a really fragile pump would seem to be a poor choice. Solutions range from mild alkalinity in the developer, to vinegar like acidity in the stop bath to close to neutral in the fix bath. I suspect stainless steel impellers or epoxy coated etc. would be fine as far as I can tell. I am guessing that a pump that would be reliable in sea water would work for me. I would like input on that.

I would rinse out the pump in fresh water after every session. Usage will be very intermittent - just emptying storage tanks into a processing tanks, and then back into storage tanks. I would foresee just one use every couple or several weeks. The prime reason to use a relatively big film processing tank is so that I don't have to spend a lot of time processing film. I'll be able to do a lot of film in a single session and not have to do session after session. If I go ahead with this, I will be able to process 18 rolls at a time and won't have to be processing all that often. The three and a half gallon size means I'm not eager to try to lift and pour like I would normally a small processing tank. Bigger means I have to find a way to get things back and forth that doesn't demand brute force. Over a gallon or so gets to be too much to handle without too much spillage.

For reasons of electrical safety, I am looking for a pump that is really well designed to keep electricity from unintended contact with solutions (and thus me). I would not use it submerged, but would want it to be robust enough that it would still be rated as safe in submerged use, since darkrooms have liquids around. Are these pumps low voltage? Or double insulated? I really don't know anything about aquarium pumps.

Could you suggest any pumps that might be suitable or any ideas I should be thinking about?

Thanks in advance!

Charlie

[Jay]

You might want to go to Dr Fosters & Smith Website or Marine Depot...Look at "top off" systems & pumps.

I think with B&W Chemicals you are going to run into crystallization and clogs in a very short time. I would look at gravity "dosing" equipment...similar to an IV bag <- manufactured by Kent & available at the same sources. I would use the dosing bags for liquid chemicals and get your water from another source.

Just off the top of my head $.02

[adifferenttank]

Thanks!

I'll check out Dr Fosters & Smith and Marine Depot sites. I appreciate the pointer!

I kinda doubt crystallization and clogs should be an issue since BW chems and color chems are routinely pumped and stored in automatic processing systems with no crystallization or clumping.

Were I to be just diluting a concentrate to working strength I wouldn't need a pump. It's getting chems back and forth from storage to processing tanks that makes me need some sort of pump. Three and a half gallons is just too heavy to try to pour accurately and safely. With a pump, I think I can transfer liquids accurately - no fuss, no muss...

In the setup I envision, I would be moving solutions at working strength, and then returning them to storage tanks and back and forth. That, rather than diluting to working strength and then dumping used solutions.