Issue with Versa Pump

[brianfarm6767]

Hello,
I have owned a Versa dosing pump for around a month now and can not seem to get it to work properly. I have contacted tech support and even been sent out a replacement and still having issues so I have to assume its something on my end.

Currently I have the pump setup under the tank with around 4 feet of line going in the return chamber of my AIO. I am only needing to dose a couple of ml of All of Reef every 24 hours. When I get the pump primed and calibrated it works great and it right on, but slowly that liquid creeps back down the tube a inch or so. When the next dose goes off it is always short because of this. I am using high quality silicon tubing that is zip tied to all joints, the provided barbs from the versa pump and just to ensure the All for Reef container isn't the issue I have the silicon tube directly in the All for Reef solution. I don't see any air bubbles in the line, no leaks under the pump or at any fitting and I don't know what else to do to try and fix the issue. Thought about going with RODI tubing instead, but if there isn't any leaks then my thought is that pump is just not holding the prime fully withing the mechanism and changing out silicon tubes for RODI shouldn't have anything to do with that.

If anyone has any insight I would greatly appreciate it.

Thanks

 

[Sisterlimonpot]

Couple things you should understand about the versa.

It has a "park" feature that usually rotates the rotor backwards when it's done dosing to park.

Low volume dosing such as a couple ml a day is a tall order for just about any hobby grade peristaltic pump.

It seems that what you're experiencing can be explained by one or a combination of these things: evaporation at the exposed tip, liquid dripping out the tip after dose and the pump rotating backwards to park.

I doubt there is anything wrong with your versa mechanically or electronically.

You can correct the evaporation and dripping issue by narrowing the outlet diameter with a pipette tip similar to this:

ONiLAB Pipette Tips 1000 UL/ 1mL 500 PCS Clear Blue Laboratory Universal Plastic Liquid Pipettor Tips Polypropylene (PP) Autoclavable https://a.co/d/dk7RZDb

The idea is that there is less surface area of the liquid exposed to air so it will have a less of a chance to evap, notnto mention that dripping will be eliminated due to the narrow tip.

You can't override the park feature, but you can rest assured that whatever backwards travel the rotor makes after dosing, it will move forward to that position before it starts to dose again.

 

[Sisterlimonpot]

Couple things you should understand about the versa.

It has a "park" feature that usually rotates the rotor backwards when it's done dosing to park.

Low volume dosing such as a couple ml a day is a tall order for just about any hobby grade peristaltic pump.

It seems that what you're experiencing can be explained by one or a combination of these things: evaporation at the exposed tip, liquid dripping out the tip after dose and the pump rotating backwards to park.

I doubt there is anything wrong with your versa mechanically or electronically.

You can correct the evaporation and dripping issue by narrowing the outlet diameter with a pipette tip similar to this:

ONiLAB Pipette Tips 1000 UL/ 1mL 500 PCS Clear Blue Laboratory Universal Plastic Liquid Pipettor Tips Polypropylene (PP) Autoclavable https://a.co/d/dk7RZDb

The idea is that there is less surface area of the liquid exposed to air so it will have a less of a chance to evap, notnto mention that dripping will be eliminated due to the narrow tip.

You can't override the park feature, but you can rest assured that whatever backwards travel the rotor makes after dosing, it will move forward to that position before it starts to dose again.

 

[brianfarm6767]

Couple things you should understand about the versa.

It has a "park" feature that usually rotates the rotor backwards when it's done dosing to park.

Low volume dosing such as a couple ml a day is a tall order for just about any hobby grade peristaltic pump.

It seems that what you're experiencing can be explained by one or a combination of these things: evaporation at the exposed tip, liquid dripping out the tip after dose and the pump rotating backwards to park.

I doubt there is anything wrong with your versa mechanically or electronically.

You can correct the evaporation and dripping issue by narrowing the outlet diameter with a pipette tip similar to this:

ONiLAB Pipette Tips 1000 UL/ 1mL 500 PCS Clear Blue Laboratory Universal Plastic Liquid Pipettor Tips Polypropylene (PP) Autoclavable https://a.co/d/dk7RZDb

The idea is that there is less surface area of the liquid exposed to air so it will have a less of a chance to evap, notnto mention that dripping will be eliminated due to the narrow tip.

You can't override the park feature, but you can rest assured that whatever backwards travel the rotor makes after dosing, it will move forward to that position before it starts to dose again.

Thank you for all the information. I did notice the "Park" feature when I was setting it up. I always make note of the water line after that is complete and then compare that the next day to see how far it has dropped back towards the pump. After the pump is completed and it rotates backwards there is an air pocked of maybe an inch or so, then the next day that air pocket has grown to maybe 2 inches.

I have a 90 degree airline barb fitting in the end of the tube so it will drip directly down into the return chamber so I should already be reducing the opening slightly.

I agree that the park feature is working correctly. If I dose 2ml and measure then see the park feature roll the liquid back slightly and then dose another 2 ml right after its spot on, its when it sets 24 hours between doses that I see it get off.

Is there a better pump for my needs? I went with the Versa just because I thought it was the top of the line and would connect up to all my other Mobius devices, but if there is something more suitable for the lower dosing volume I am willing to make a change so I can stop tinkering with this one.

Thanks

 

[Sisterlimonpot]

Are you dosing all at once? Or throughout the day?

Can you provide a photo of this elbow. I think your best bet is to restrict the effluent to a tiny orifice. Perhaps that's what the elbow is doing, but if you have any test kits with 1ml syringes with the tip that allows precise control of drops, you can fashion that to the end of your effluent.

Is there a better pump for my needs?

I honestly can't think of any other peristaltic pump that uses precise steps (from the drive motor) that is more capable of doing what you want, micro dosing.

I'll have to look through my old photos to show you what I did to solve the evaporation of the fluid at the effluent tip. I designed a pipette fitting that fit into a push to connect that restricted the orifice to 0.4mm.

 

[brianfarm6767]

Are you dosing all at once? Or throughout the day?

Can you provide a photo of this elbow. I think your best bet is to restrict the effluent to a tiny orifice. Perhaps that's what the elbow is doing, but if you have any test kits with 1ml syringes with the tip that allows precise control of drops, you can fashion that to the end of your effluent.


I honestly can't think of any other peristaltic pump that uses precise steps (from the drive motor) that is more capable of doing what you want, micro dosing.

I'll have to look through my old photos to show you what I did to solve the evaporation of the fluid at the effluent tip. I designed a pipette fitting that fit into a push to connect that restricted the orifice to 0.4mm.

Sorry for the overly blue photos. In the photos you can see where the water line is, near the adjustment screw on the back of the bracket. Last night when the dose was complete the water line was just past the furthest left holder nearest the outlet of the hose. So it has either evaporated back that far or siphoned back that far, which from my measurements is around .75 ml missing when I run a manual 2ml dose and only get 1.25ml or thereabouts.