standards, and a length of metal coat hanger to blouse the
dyed water hose.
I was fairly cavalier in attaching all of these bits to the
plastic box, using #6 machine screws and zip ties. These
served to mount the main circuit and the LED standards
while the pump sported four suction cups on its base. I
was able to keep it from sliding around after cleaning the
bottom of the box with denatured alcohol.
The pump I bought came with a pile of extensions and
adapters. I found that the one that converted the output to
1/4” OD plastic hose was the best. Not surprisingly some
drip irrigation parts worked the best for the hose and the
emitter (a 2 GPH dripper.) As you can see in Figure 1,
I simply zip-tied it along to the coat hanger. Bending the
coat hanger wire to attach it to the basin was a trick
The PCBs and/or a complete kit for this project can be
purchased through the Nuts&Volts Webstore at
www.nutsvolts.com or call our order line at
(Figure 6). The final height and orientation is unimportant as
it can be compensated with by the pump speed control.
The UV LED standards were built quite easily using
some more protoboard and Chem Wick desoldering braid.
I placed the LEDs every 0.6” and soldered them in parallel
on the back of the protoboard (Figure 7). A dab of hot
melt glue on the back secured the leads enough to allow
refocusing. The pump came with 15 feet of cable so I
chopped it up to wire the standards and all of the
components on the main controller board.
The final — and most messy — part of the project is
creating the dyed water. It turns out that a yellow Sharpie
Accent highlighter contains everything you need. Simply
pop out the end cap, extract the dye-soaked core
(Figure 8), and wring it out in the water of your catch
basin. If you’re building this project with your kids, you
will want to hand this off to them as it’s the most messy.
In my prototype, I found that two highlighters contained
plenty of dye to color a quart of water. And they only
cost about 25 cents apiece. (When you’re done, drain the
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