A: There is a very easy and effective way to sterilize the pump-tubing set - you can re-circulate hydrogen peroxide through it. The "drugstore grade" 2% hydrogen peroxide works fine for this. Get about 250 ml of 2-3% hydrogen peroxide and re-circulate it through the pump for 5 minutes at room temperature. While alcohol is pretty good at killing most bacteria, hydrogen peroxide is very effective at killing both bacteria and fungus, yet it is much more compatible with the internal components of the pump than bleach (which is not recommended). Autoclave 2 bottles of distilled water along with your media. Run one bottle of hot water through the PourBoy before you pour your media to preheat the tubing and pump and wash out / sterilize any contamination. Run the second bottle through the PourBoy *immediately* after you pour the last plate to wash out any media before it can gel in the system. You can also autoclave your tubing before use. Remove the tubing from the pump, wrap it in aluminum foil, and autoclave it thoroughly. Use the foil to make sure that nothing touches the outside of the input tube so that it remains sterile before it goes into the medium. Of course, it is also important to do negative controls when looking for the source of contamination. Hopefully, you already know that there is no contamination already present in the "sterilized" media or the Petri dishes. The next time that you pour a batch plates you could manually pour a few using a sterile pipette to make sure that the source of the contamination is not upstream from the PourBoy.
Here is our recommended practice for pouring plates:
1) Remove the tubing from the PourBoy's pump, and wrap it in aluminum foil.
2) When autoclaving your media, also autoclave the PourBoy's tubing and 2 bottles, each containing 1 liter of distilled water.
3) Optionally have 500ml of 2 or 3% hydrogen peroxide on hand. Ethanol or isopropanol is also acceptable, but generally less effective.
4) Put the input and output tubes back on the PB4 with care so as not to contaminate the parts of the input tube that will be in contact with your media.
5) Optionally pump some hydrogen peroxide through the system for 2-3 minutes. It can be recycled back into its bottle or discarded. it can also be filled into the system and paused so that the internal parts are being bathed.
6) Insert the input tube into the first bottle of hot distilled water and run at least 500 ml of hot water through the system, discarding it. In most cases, the hot water is enough to kill and / wash away any small amounts of contamination without the hydrogen peroxide step. The hot water is necessary if you are going to pump gel-based media (such as agar) because it will preheat the tubing and pump, preventing gelation.
7) Transfer the input tube from the first hot water bottle into your media, and pump media through until the water has been displaced.
8) Pour your plates. It you need to pause for more than 30 seconds, direct the output tube back into your media vessel and recirculate the media, by using an automatic mode pour setting, to keep the tubing hot and prevent gelation within the tubing and pump. Even 1 minute of stationary medium could cause an unpleasant gelling problem.
9) Immediately after pouring the last plate, transfer the input tube into the second bottle of hot water, and pump it through to remove any residue of media, which would otherwise gel in the system and/or be a source of nutrition for a contaminant. It is important to use distilled water, because, if allowed to dry out, the precipitated minerals from residual tap water could cause the pump to stick/jam.


 A: The PourBoy can deliver liquid volumes precisely from 0.1 mL to 999.0 mL. The precision is controlled by a microprocessor, which ensures consistency of aliquots. Precision using the standard pump is typically within 2%. Reproducibility can be affected by hydrostatic pressure - the difference in height between the input medium and the output dispensing tube. Do what you can to minimize changes in this height over the course of dispensing. This difference is more pronounced with the High Speed pump than the Standard pump. 

 A: The PourBoy has two dispensing modes, Manual and Automatic. In Manual Mode, the set volume is dispensed each time the foot pedal is pressed. In Automatic Mode, you can set the pause interval between deliveries of media, and press the foot-pedal once to start and once to stop the cycle. 

 A: The currently available "Medium Speed" PourBoy pump dispenses media at ~350-400 ml per minute at full speed, and an included variable-speed option allows you to set slower speeds for dispensing small volumes into small vessels. Our previous "Standard Speed" pump delivered ~180-200 ml / min and our previous "High Speed" pump could dispense liquids at a rate of ~800ml/minute. You can check with us if you need one of these older pumps to see if we have any in stock. Both versions have a variable speed option. Without the variable speed option, the pump always runs at its maximum speed; the variable speed allows it to slow down to flow rates below maximum. 

 A: We ALWAYS recommend that you purchase an extra of pump-tubing set (PB4-PTS) with your PourBoy sterile media dispenser in case you encounter any problems with the pump or tubing getting clogged. This way, you can quickly change out the pump-tubing set, continue working, and worry about cleaning it later. 

A: It is always best to pour sterile media in the hood to reduce the chance that mold spores or bacteria or dust will fall into your media. We recommend avoiding contamination at all costs! Also, if your hood has laminar airflow, that will also help to evaporate any condensation that forms on the Petri dish lids and to cool and gel the plates more quickly. 

 A: To avoid contamination, it's best not to wait at all. Before pouring the plates, if you allow the media to cool (while stirring on a hot plate with a magnetic stirring bar) to about 45-50°C, then you can close the dishes immediately. The resulting condensation should evaporate after several hours. We recommend first forming a stack of plates, for example, 5 plates tall (or 10 plates if you have good balancing skills). Then, we suggest lifting the top 4 plates, plus the lid from the bottom plate and shooting the media into the bottom plate. Next, lower the stack, putting the lid back on the bottom plate, and lift the top 3 plates plus the lid from the second-to-the-bottom plate, and shoot media into that 2nd plate, etc. It is important not to move the plates around after you have poured them and before they fully gel, to avoid a messy surface. You'll get the hang of it in no time!

 A: The PourBoy 4's tubing can be autoclaved indefinitely. It is made from medical grade silicone rubber and is impervious to autoclaving. However, the actual pump is not and, while it might survive autoclaving, there is a good chance that this could cause some of the plastic parts to distort, which would make the pump stop working. 

 A: We recommend holding the output tube in your hand and aiming it into the dishes at a 30-45 degree angle. If you find that the stream is not smooth enough or dripping at the end of each dispensing operation, you could insert a piece of smooth glass or plastic tubing at the end of the output tube to act as a nozzle. Do make sure that the nozzle is still being sterilized with the same procedure you use on the rest of the tubing. 

 A: The vibration from the pump could cause the weight of the tubing outside the flask to pull on the tubing inside the flask. You can try taping the tube in place or shoving something (such as sterile aluminum foil autoclaved along with the media) against it at the neck of the flask to address this.

 A: The silicone rubber tubing provides some insulation, so you probably will not need a handle when touching it. You can wear gloves to provide an additional layer of insulation.

 A: To make a piercing adapter tip to inject large volumes, we suggest a large-bore needle / cannula with an O.D. of slightly over 1/8 inch so that it fits tightly inside the PB4's output tube. If it were for much smaller volumes than 40ml, you could use a 1cc syringe body with slip-tip output as an adapter for standard luer-lok / slip-tip needles that are available up to about 16 gauge.

 A: The PourBoy base unit and coil have no moving parts (except the push buttons) and are generally very robust. The item with the most variability and sensitivity is the pump cartridge because it has small springs and small apertures that can get clogged with gelled agar or particulates. For some people they last years, and for others they might last less than a year. We suggest keeping a spare pump on hand at all times so that you can change pumps and keep going in the event that the pump gets clogged. Over the years, a few people have also managed to damage the foot pedal or the plug / receptacle for it.