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Old 02-01-2009, 09:56 AM   #3 (permalink)
Join Date: Jan 2009
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Default Re: Automatic Continuous Feeder - DIY

Part 3 of 5

Here's why you need to stick to this model pump: There are hundreds of medical pumps on Ebay. You WILL be tempted to get a cheaper one (I got two cheapies, one for just $25! Was a complete waste of time.). Here's why you want to pay the extra money and stick to this Zevex model:

Small Dosages: This is the important one, and you probably won't find out until you get the wrong pump in your hands (I didn't). Most enteral and IV pumps are 1.0 ml minimum. This means that the smallest amount it will pump at one time is 1.0 ml. That's a LOT of concentrated food! (One mysis cube is 3 ml.) I'm currently dosing 10 ml/day. If I had to dose 1.0 ml at a time, I'd have to wait to dose about every two hours. And a 10g nano could only dose this once a day. So having a 0.1 ml capability opens up an entire world of feeding. The other advantage of small dosages is that you can dose even more often than once per hour. I could dose 0.1 ml every 15 minutes, and still end up with 10 ml/day.

Interval Feeding: This is the other important one. Many pumps don't have this option (and they don't list this info on Ebay, so you won't know); instead they dose a constant amount, all the time. If you dosed constantly, your most aggressive fish would hang out at the tubing and eat everything before the other fish and corals got anything. You need to burst out all the food at one, every so often. Of course, a coral-only tank is different, and fortunately the Zevex pump does continuous pumping also.

Not for IV use: IV pumps are those huge ten or twenty pound contraptions that are mounted on a pole in hospital rooms. They are very complex, and many of them have computer connections. And they are very expensive. The only way to get one under a few hundred dollars is to get one from the 1990's, but then it becomes impossible to finds the "drip sets" (or "cassettes") that you MUST have for it to work. I bought two of them, and could get neither to work without the cassettes.

Small Size: IV pumps are just too big to set on top of a tank. Even some enteral pumps are too big. But this Zevex model is probably the very smallest there is of ANY pump. And certainly the thinnest. Most pump pics on Ebay don't show or tell you how deep the pumps are. They look small, but when you get it, it's 9" or 12" deep. The Zevex is just 2" (5cm), including the tubing cover.

Waterproof: Very few pumps of any type are waterproof; they were made for the hospital room, not for walking around outside. But this Zevex pump, if operating on batteries, would actually work underwater if you dropped it in your tank.

Current Model: This model is NEW, and is CURRENTLY (January 2009) being manufactured (it just won the product of the year award for medical feeding devices.) This means that you will be able to get the feeding bags ("delivery sets", "pump sets") for many years. A delivery set (usually with a feeding back attached) is required to run the pump, since the pump detects that the proper set is installed. Delivery sets are cheap to buy, but impossible to DIY.

Looks Nice: I think this pump is the best looking of all of them. You won't see it very much on top of a larger tank, but on a nano it would be very noticeable.

Easy to Use: After reading the instruction book, you can set the options up in about 10 seconds. Adjustments like dosage and interval take about a second to adjust. It's an amazingly well built pump; I really think it's worth the $1500 retail.

Note: Some folks have experimented with syringe pumps. But syringe pumps are very large, not battery operated, and unless you get the expensive "retracting" models, then you have to take the syringe out and retract the plunger each time it bottoms out. Plus I'm sure these pumps are not waterproof. After looking at syringe pumps long and hard, I finally gave up and kept searching until I found the Zevex pump. I can see why continuous feeding has had a rough start until now.

Important: (1) Make absolutely sure you get the AC adapter with the pump. The adapter uses a proprietary waterproof connector to the side of the pump. You cannot use any other type of adapter, and you cannot buy this adapter anywhere else. (2) Get several "delivery sets" (also called "feeding bags" or "pump sets"). You have to replace them every so often; see recommendation further below. (3) Ebay requires the seller of medical devices to say something like "you must be a licensed medical professional to buy this product"; but don't worry, they never actually ask.

Pump operation:

AC power connector for charging battery (does not need to be connected to operate):

Open the cover:

The "delivery set" or "pump set", which is the blue flexible silicone tube, is stretched over the big black wheel to the left:


Close cover:

Cut the tubing so that it barely reaches into your tank water:
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