Japi’s blog

Fishy warmth monitoring

Continuing my geeking-out of my aquarium, I wanted to have temperature monitoring. I have a pile of Dallas-Maxim DS18S20 1-wire temperature sensors left over from when I added temperature monitoring to my house, but the bare DS18S20 is not going to like being submerged. Since this is an aquarium with fish I had to be careful with what I use to waterproof it, anything that leeched metal or chemicals would be ‘bad’. So, the obvious solution was to use aquarium epoxy (normally used to stick rocks together, or attach coral to rocks.

The DS18S20 is pretty neat because all you have to do is wire it directly into the 1-wire sensor network. While the network is called ’1-wire’, it actually needs at least two wires (data, and ground), and a thrid optional line for power. Since I have a large sensor network I use the power line (it helps reliability with large networks). The standard way of hooking these things up is to use an RJ-11 ports/connector, so I attach the sensor to a piece of Cat 5E cable, and crimp an RJ-11 connector on the other. Here is a sensor badly soldered onto Cat 5E:

To prevent the wires from shorting when, I coated them in liquid electrical tape. This stuff is supposed to be waterproof, but I don’t know if it is fish safe. I wouldn’t recommend just using it to waterproof the DS18S20.

The probe was encased in Marineland Holdfast aquarium safe epoxy. This stuff is really easy to work with, it comes as a stick that you break a piece off from, then knead it with yours hands till it is a consistent grey-white. Once that is done, you have 7 minutes to work with it. I rolled it between my hands to make a rope, then flattened the rope on my workbench, put the probe in the middle of it, wrapped the flattened epoxy around the probe, that rolled the probe between my hands again to turn the epoxy+probe back into a rope. Care was taken to ensure that of the probe with the sensors was a nicely rounded, and thick enough that the water shouldn’t get through it once cured. Curing was only supposed to take an hour, but the probe still was slightly flexible 12 hours later (but the surface of the epoxy seemed to be pretty hard), maybe it took longer because of the thickness of the epoxy, or the temperature in my basement (only about68-70F). Here is what the probe looked like after curing:

I mounted the probe in my tank by using a twist tie to fasten the Cat 5E tail to the output of the filter. Since I already pulled a 1-wire network run to behind the tank for the heater powre monitoring, I just plugged the temperature sensor into a second jack I added. The probe tip is about 3-4 inches under water now, and I am hoping the filter output is circulating the water well in that area. You can see the probe in the upper left corner of this picture:

Reading of the probe is done using digitemp in Linux, under normal use logging once a minute. For testing I briefly had samples being taken once a second. The probe is surprisingly responsive, with a 17 degree Fahrenheit temperature change settling in less then 90 seconds:

The probe has been in the water for about 2 days now and is still functioning perfectly, hopefully it will stay that way for years.

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Teaching a power strip new tricks

The new aquarium I am setting up has dual 250W Visa-Therm (now Marineland) Stealth heaters to keep the temperature up at around 82F, even though my house is often only 60F when I am too cheap to run the heat. Being a geek, I wanted to be able to tell how often the heaters are running. Thanks to an aborted project to monitor power usage of the server rack in my basement I have a spare iButtonLink MS-TC Temperature and Current MultiSensor, which measures how many amps are passing through a wire using a DS2438. This is done using a clamp-on current transformer with a 1-20A range (under 1A the values are erratic), which translates into 120-2400 VA, or the same range of Watts if the power factor is at unity (1.0). A heater is an inductive electrical device which thankfully does run at unity, making this the perfect device for measuring the draw. The trick with a clamp-on current transformer is that you have to wrap it around just the hot line, not the ground/neutral. This means you need to split apart a cord to isolate the hot line. In order to do this safely I decided to try to cram the transformer inside of a power strip.

I started with a Belkin surge-protected power strip, since the bulge from the surge protection circuit looked like it would be big enough to stick the transformer:

The surge protection circuit was yanked to make room for the transformer, and a new hot wire was added since the existing ones were too short (due to the hot going through the surge protection circuit). I also drilled a small hole in the side of the power strip casing to feed through the output terminals from the current transformer, to attach to the 1-wire current MultiSensor (these wires are low voltage/current, and are safe to have exposed, they do not directly connect with the 120V AC line). It was a tight fit, but everything fit with just the removal of one unused bit of plastic in the power strip case. The ground of neutral wires go under the transformer, while the hot goes through it. The switch still works too:

The back of the power strip case was reattached, the transformer attached to the and the sensor attached to my home 1-wire network (already in use monitoring temperatures in parts of the house). The finished device actually looks decent:

Reading of the values was done with digitemp in Linux (version 3.5.0). The output looks like this:

japiserv:/tmp# /usr/bin/digitemp_DS2490 -q -A -c /data/sensors/digitemprc_tank -t0
Oct 13 05:58:22 Sensor 0 VDD: 4.57 AD: 0.39 CAD: 1 C: 20.78


The AD field is the voltage output from the current transformer. If it is 0.20V or above (indicating at least 1A), you do this transform:

$amp = (($AD - 0.20) / ((3.78 - 0.20) / 19)) + 1.00


The zero value is 0.09V, so if the volt is between 0.09 and 0.20 then the reading is below 1 amp (and out of spec of the current transform), but to get some sort of value I used this transform:

$amp = ($AD - 0.09) / (0.20 - 0.09)


Anything 0.09V and below is just considered zero. The numbers that came out were actually fairly accurate when compared with the output from my Kill-a-Watt meter. I used a 100W incandescent light bulb for a low-power test, and a 1300W toaster oven for a high power test. Both of these devices have a power factor of 1, and the results were within 5% of the Kill-a-Watt meter. I might be able to get more accuracy by tweaking the 0/1/20 amp voltage points to match exactly with loads taken at normal temperature conditions in my house. To convert the amps to VA (which is the same as Watts at PF=1), I multiplied with 120V (my house line voltage).

What did not work at all was measuring the power consumption of the Coralife Lunar Aqualight that I use to light the aquarium. This light uses 4 65W compact fluorescent bulbs, driven by two electronic ballasts (with independent switches). The power factor on these is about 0.57 (which would cause a huge difference between real power (wattage) and apparent power (VA), but even the VA readings from the MultiSensor were completely off, reading 763 VA compared to 318 VA on the Kill-A-Watt. I think this is because the CF ballasts are non-sinusoidal (power consumption is only a specific points on the 60Hz AC wave), and to read those you need a true RMS ammeter. A true RMS ammeter measures the current on the line many times per second, then uses a root-mean-square calculation on that data set to output a more accurate number. So, measuring load from the heaters works fine (PF is constant, and the power draw is the same across the AC wave), but measuring the lights was definitely not possible.

For data logging, I wrote a cron job that retrieves the amps from the MultiSensor once a minute, and uses RRDtool to log the values. RRDtool also generates nice graphs, and I can generate nice graphs, and put them in a status page for the tank:

The graph should have 3 general data levels: 0 watts when neither heater is on, 215W when one heater is on, 430 W when both heaters are on. Values between these points indicate that there were two data points in the same step, that were at different levels and RRDtool has averaged them. As you can see the heaters have to do quite a bit of work to keep the temperature up at 83F (the room was around 68-70F during this testing), but on average one heater could keep the tank at temperature, it would just need to run nearly constantly.

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Extra bonus super sized aquarium, now with excessive-depth!

As seen previously on this blog I had a 30 gallon (36″ x 12″ x 17″) aquarium in what is labeled the ‘Family Room’ in the floor plan for my house. The tank was about 4 feet from a 35000 BTU wood burning stove, as shown in this old Christmas-time picture:

I was never really happy with the tank near such a large heat source, so I never kept temperature-sensitive fish in the tank. Recently I have wanted to be able to keep larger fish, and so I have taken the opportunity to upgrade the 30 gallon tank to a massive 110 gallon extra-high tank, empty and not quite ready for use (and surrounded by mess from tearing down the old tank, and setting up this one):

The tank is 48″ x 18″ x 31″ (same footprint as a 75 or 90 gallon tank, just much taller), constructed of glass by Perfecto (now a division of Marineland), and weighs about 182 pounds empty. The stand is a Big Al’s Stingray, which I chose because I liked the open shelves in it, but it still has a compartment large enough to hold a decent sized filter. The next step with the tank is to paint the back black so you can’t see wires and hoses through it. On previous tanks I have stuck black cardboard on the back, but I think with a tank this size it won’t stay in place.

Expect more posts as I get more equipment for the tank and complete setting it up.

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Garage wall mount for kayak

As part of an on-going effort to reclaim my garage from the hoards of clutter in it, I mounted my kayak to a garage wall this weekend.  To do this I had to remove a shelf that a previous homeowner had built, that was covered over by peg board anyway (making the shelf only useful for storing long piece of scrap lumber).  Once that was done, I was left with a nice chunk of wall for putting the kayak on.  To hang the kayak, I used a pair of 15 inch shelf supports, attached to the studs with a few lag screws I had around the house.  The supports seem very sturdy, and I don’t worry about them being able to hold the 60 pounds of the kayak.  On top of the supports I put foam padding, in the form of door/wall protectors, that are designed to be stuck to a garage wall so you don’t bang up your car door/walls if you open the car doors too much.  They were the perfect size (also 15 inches), and the foam was stiff enough that it shouldn’t tear from kayak abuse.  It is held in place with double sided tape.  Finally, the kayak is secured to the wall with a pair of bungee cords.  Total cost for the project was about $25.  Here is what the final result looks like, in my still-very-messy garage:

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Precision electrical upgrades, with a saber saw.

After the success of the upgrade of an aquarium light from 30 watts to a 55 watts, today I crammed the leftover 30 watt light into a 20 watt light that I use on top of my 30 gallon aquarium.  This one was a little trickier, since the light was not designed to be used in a retrofit situation, and was also the completely wrong shape, and number of bulbs.  The light to be upgraded is an All-Glass 36″ strip light, with a single 20 watt, 24 inch long fluorescent bulb.  What I am upgrading it to is two 15 watt, 18 inch fluorescent bulbs.  Here is what the parts two lights looked like pre-hacking:

The perspective is a little odd, because the long strip light is sitting on it’s side, but it should be obvious that the dual-light won’t fit into the skinny single-light enclosure.  So, the obvious solution was to take a saber saw and cut the dual light into two smaller lights, being careful not to damage the ballasts or wiring.  Once this was done, I could cram both lights into the enclosure (after removing the existing single 20 watt light), by staggering them across the length.  The two bulbs won’t be centered correctly front-to-back, but it shouldn’t make much difference in this tank.  The lights are held in place by screws, one going into the existing mounting hole to hold the right lamp in place, and two going through the back of the enclosure to hold the left lamp in place.  Wiring was connected to the existing cord/switch.  I also mounted two Current Lunar Link Lights to the excess bits of plastic on the lamps, and ran the cord for them through a hole drilled in the back of the enclosure.  The completed assembly looks like the total hack-job it is:

Surprisingly, it actually works:

Since there are independent cords for the lunar light and the fluorescent light, they can be turned on/off independently.  I am using Z-wave for remote control of both lights, since why would anyone use a simple timer, when they can use a Linux server to control aquarium lights?  The tank is much brighter now, the extra 10 watts distributed more evenly across the tank makes a big difference.  I am hoping my plants will be happier too, I have never had much luck getting good growth out of this tank.

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Night lights for your fish

A common problem for fish is not being able to find the bathroom when the house is dark.  To solve this issue, various manufacturers market “Lunar LED Lights” for aquarium use.  I have purchased two separate makes of these, and have compared their lighting ability in my 54 gallon corner bow-front tank.  The two that I have are the Coralife Lunar Blue-Moon-Glow and the Current Nocturnal Blue, with an additional link light.  Both generate light with a 470nm wavelength, but the designs are fairly different.  The Coralife is a single LED, with a permanently attached cord/transformer.  If you want multiple lights, then you need to use multiple transformers.  The Current light has 2 LEDs per module, with detacheable cord/transformer, and the modules are designed to link.  I have two modules, and the modules are attached to each othre with a 2 foot long cord (included).  The Coralife fixture is supposed to be about 1 watt, and it’s power transformer is rated for 1.8 watts (4.5 volts, 400 mA).  The Current fixtures do not specify their wattage, but it’s transformer is only rated for 1.8 watts (6 volts, 300 mA), and that transformer is supposed to power 7 modules (or about 0.25 watts per module).  So, with 2 modules, I am only getting half a watt of light output.

Lets compare what the two look like.  I used a 3.2 second exposure on my Canon SD900 camera, set up on a tripod in a room that was dark except for the glowing of power lights and of course the LED lighting on the tank.  Fish are blurred because they wouldn’t sit still no matter how many times I asked them to.

First, let’s look at the Coralife.  It has a pretty good spread for a single light, and for the shape tank it was easy to work with, just laid it onto the glass canopy on top of the tank:

As you can see, it is a bit spot-lighty, because it is so bright.  It does a good job since the tank is tall, giving it the distance it needs to be able to completely light up the gravel.  For a long tank, you will need multiple lights.

Next up with have the Current lights, I have them spread out about 12 inches apart, both just laying on top of the canopy.

They are obviously much darker, having trouble lighting up the plants like the Coralife did.  But, at the same time they are less spot-lighty, since they are not as overwhelming.  You can still see on the water surface where they are placed, but it is not as over-the-top.  Maybe with one more light it would be the perfect amount of lighting, but then it becomes annoying running wires all over the canopy and laying out the lights for balanced coverage.

Finally, I took a picture with both the Coralife and the Current lights on at the same time.  This was not surprisingly very bright:

Too much light for my taste (it really shows off the algae on the back sides of the tank), but might be good for a reef tank. I will stick with the Coralife for the light in this tank, and use the Current lights on my 30 gallon tank.  It’s 36″ length requires two lights, and the smaller output of the Current lights shouldn’t overwhelm the tank.  In simple tests with the Coralife on the 30G tank, it was way too bright, and didn’t cover half the tank evenly.  The Current lights also aren’t the most even light in that size tank, but since they are darker it isn’t as noticeable.  I suspect if I had a 55G or other larger-size long tank that 2 or 3 Coralife lights would do a nice job, and have the handy feature of mounting directly to the body of Coralife lighting fixtures (which I don’t have, so it isn’t very handy to me).

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Peculiar packing peanuts

Drs. Foster and Smith, from whom I order far too much fish-related equipment, use biodegradable packing peanuts in their shipments.  This makes getting rid of the peanuts easy, if you don’t want to reuse them:  just put them in in some water and they disappear.  They are even supposed to be compost safe, being made of some sort of starch material.  What you have to be careful with, if you are playing with an aquarium and unpacking your newly-arrived toys, is that this doesn’t happen:

Remember, if things degrade in water, and your hands are wet, the peanuts will decompose and stick to your hands.  Of course, it isn’t a big deal…just run your hand under some water and all the packing-peanuts wash off/disappear.

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Cross bars replacement on a 2002 Subaru Impreza TS

I have a 2002 Subaru Impreza TS (which is the wagon model), it has been a good car, I have driven it around the country, and back and froth to work a few times too. I also have a kayak, a 12 foot Old Town Dirigo 120. Previously I had been moving the factory roof rack, using foam blocks to protect the kayak, and a bunch of tie-down straps to secure it. While this worked OK for short drives at low speeds, the kayak seemed to wobble quite a bit at interstate speeds on a long drive. The factory cross bars are not terribly stiff, they actually bend when I tie the kayak down on them and I suspected they are where the wobble comes from, they are probably bowing up/down as I drive. So, I decided to replace the cross bars with an after market set, since they feel much stiffer. This will also allow me to use fancy rack accessories without needing to get adapters.

The first step was to remove the old cross bars. This is easily done just by removing four screws (4mm hex head), each on top of one of the brackets holding the cross bars to the rails:

Once the screws are removed, the bars just pop off, and you are left with the factory rails. The rails don’t need to come off thankfully. Now we just need to install the new cross bars. I am using the Yakima 48″ cross bars, with their Low Rider towers. They clamp directly onto the factory rails (just by hand-turning a pop out handle-thingy), no other adapters needed (thankfully, since a set of Low Riders and the cross bars totaled about $170 even on sale). I also installed lock cores, though this wasn’t necessary (some towers require the use of lock cores, the Low Riers do not). This will prevent someone from unscrewing and walking off with my expensive rack, or at least slow them down/ inconvenience them slightly. No tools were required to install the cross bars/tower, and they were easy to install. I spent more time measuring for positions then doing anything else. the bars overhang the rails by about 4 inches on each side in the front, and about 5 inches on each side in the back. It does not stick out enough that I am worried about hitting my head on it when getting into/out of the car.

The next bit of hardware to install was the Hullraiser kayak mount, also made by Yakima. This too is a tool-free installation, and very easy. Just attach some pads to the mounts with some snaps, attach a couple of connectors to the cross bars, and tighten the mounts to the connectors using a set of bolts with thumb-screws. Hand tightening made them reasonably tight, they wouldn’t move along the bars, but you can rotate them along the round cross bars. I don’t know if this is good or not, if I don’t like it I can also use some channel-lock plies to tighten them down more. Here is the rack with the mounts installed:

And of course we need to do a test with the kayak. The one drawback I see with this style mount is that with a wide kayak like mine, it ends up being very tall. So, before putting the kayak up on the mounts, I threaded the straps through the back of the mounts, and hung them off the far side of the car (these buckles are wrapped in soft rubber, so it won’t scratch/ding the car when tossing it around). After putting the kayak in the mounts, I just tossed the two loose ends back over the kayak, and I could tighten it down easily. Since this is a long load, it needs to be fastened at the bow/stern, using the provided straps. These are much easier to get onto the kayak then my old straps, mostly because the kayak is now much closer to the side of the car. The hooks that attach to the car are loose from the straps, which I don’t like. I will probably bend the hooks to be permanently attached instead so I don’t lose them. These straps do conveniently come with a bit of vinyl hosing around a small section, so it straps don’t rub the paint off your car. Unfortunately, the front one is way too short, but I can pick up some vinyl tubing from Home Depot to fix that. Here is the kayak completely mounted on the car:

I took it out for a test drive and it seemed to be much more stable, and even with some crazy slaloming, it didn’t feel like it was moving around. Visibility is better because the bow/stern straps are only on one side of the car (I put the kayak on passenger-side to take advantage of this). There was a noticeable bit of wind noise, this was most likely caused by my positioning of the kayak, it was not completely straight and the back of it was further out then the front, this might have caused wind to be caught in the cockpit of the kayak. More testing will be needed to determine the optimal position. One nice unexpected side effect of the different kayak position is that I can open the rear hatch of the car much more now with the kayak on the roof, compared with the direct-to-rails mount approach of the past. Very useful for last-minute packing.

In conclusion, I spent about $300 (thanks to REI’s 20% off sale) for the towers, bars, locks, and Hullraiser just so I wouldn’t feel like my roof rack was going to crack in half and my kayak would go flying down the NJ turnpike with the remains of the cross bars.

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Aquarium lighting upgrade

I have a 54 gallon corner aquarium, that came with a little All-Glass Aquarium twin tube light (24″ tubes, 15 watts each), which isn’t much light for a fairly large/deep tank. A friend of mine who is very fishy-equipment-smart suggested getting a retrofit kit for it, which is what I ended up doing. Aquarium Hobbyist Supply sells a kit that for a 55 Watt compact fluorescent bulb that looked like it would fit into my existing plastic enclosure, so I ordered it, procrastinated for 3 and a half months, and just assembled it.

It is not a drop-in replacement for the existing twin tube light, there were bits of plastic that supported the old bulb assembly inside the casing that I had to cut away with a pair of wire cutters. Once these were trimmed down a little bit, the new polished aluminum reflector fit in without a problem, and I could reuse two of the existing screw holes to attach it. There was still just enough space in the enclosure to also fit the electronic ballast. Wiring everything up is very easy, just follow the color-coded wiring diagram. Everything you need is included in the kit (wire nuts, cable clamps, ground screw attachy thingy, etc). The final assembled light actually looks like something you could buy, not something put together by hacking apart a basic plastic light (pictured with the old light fixture):

I have a 6700k bulb in the light at this point, it is very bright (compared to the old light, by aquarium standards this is still a not very powerful light), and the plants appear a much brighter shade of green. It does not appear to be getting alarmingly hot, likely helped by the existnig light already having vent holes. The only drawback of the light is that it really lights up any debris in the tank, no skipping water cleanings with this thing.

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Low-tech aquarium decor.

I have a 30 gallon aquarium that was originally set up about 7 years ago, in my previous house. It hasn’t been rebuilt since then, it was even moved partially full of water (a fun thing to attempt to do, I wouldn’t recommend it). As there are not currently any fish in it, I decided to take advantage of it’s emptiness and do a complete rebuild. I removed the under-gravel filter which was not effective anyway, drained all the water, removed the old gravel (which was a blue-green/black mix that I was no longer fond of), and scrubbed the tank down, and put new cardboard along the back (the black background makes the tank look much nicer when it is lighted).

With the tank all cleaned up and ready, I filled it with about 45 pounds of river pebble gravel, for a more natural look. Wanting to continue the rock/stone theme, I pondered buying some fancy aquarium rock, but instead decided to use some of the excess Pennsylvania fieldstone I have in my backyard, purchased when I was built the pond in my backyard (I bought 9000 pounds of stone in total, most of the excess has been put to use as walls for raised flower beds). To try to minimize the impact the stone would have on the eco system of the aquarium, I washed the stone, and then boiled it for 30 minutes. This is a rather time consuming process, since my largest pot is only 10 quarts, and it takes about 20 minutes just to get the water and stone up to boiling. It took three pots to boil all the stone, which totaled about 50 pounds.

I wanted to build up a mound of rock in one corner of the aquarium, and I wanted to make caves throughout the mound so the fish that will soon be occupying the tank would have someplace to play. Most of the caves were just dead ends, but there is one cave that the fish can swim straight through, made by having a big rock suspended by 4 stacks of small rocks. Here are the stacks of rocks before the big rock capped them, creating a nice little pathway for fishies to swim through:

I attempted to keep the rocks mostly level, both for ease-of-stacking and since I think it looks more natural that way. Fieldstone naturally forms as sheets, and ideally you would arrange the rock so that the colors and sizes would match, but sice this was just leftover bits I couldn’t be too picky about which pieces I used. I think the pile came out ok:

The final touch was to get some more plants to decorate the rock. I pulled some excess java ferns from another of my tanks, and shoved their roots under the stones in various places. Java fern doesn’t like gravel, but it loves latching onto driftwood and stones, so they should do well in this setup.

As you can see, the lighting of the stone stack isn’t the best, this is because the strip light is only using a 24″ bulb, even though the tank is 36″ long. This will need to be upgraded for the plants to be happy. I am also considering adding more stone, possibly as a small stack in the right corner to help balance out the tank. It will reduce the water volume even more unfortunately, but I don’t plan on keeping a large number of fish in the tank, so that shouldn’t be a huge problem.

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