DIY project: making a double fluorescent T8 light bar

by Frank Panis

Don't we all like fancy gear for our tanks? Most probably yes, but equipping a fairly large tank with all latest technology can be quite expensive. Last year I also found out that light doesn't come cheap as I needed a new lightning solution for my 750L planted tank. The minimum requirement was that it could be built into a slim hood and that it had to be powerful enough to allow the plants to grow. The only choice I had was buying a 2x80W fluorescent T5 light bar. The total cost of a complete set with lamps and matching reflectors was about 300 Euro in total! Of course I was very satisfied with the result, as the plants in the 750L tank flourished from day 1 with only very slight traces of algae on the wood.

Meanwhile the kitchen tank was equipped with a 150W MH light which worked fine, but I had some doubts about the durability of the enclosure. After all for safety reasons we don't want electricity and hot humid air to get joined. Also a 150W MH lamp in a 1500L cichlid tank with no plants at all guarantees the perfect recipe for unlimited algae growth. At first I liked this as I saw the health aspect for the fish, but too much became really too much! Even with a 80% water change every 2 weeks I needed to clean the windows every 2 days in order to see my fish swim. When on top of that the tank got "infected" with BGA the maintenance became a real nuisance and I decided to empty the tank and replace the light with a less powerful unit at once. 

Fluorescent light was on my wish list, and again such a double T5 light bar looked quite attractive to me. At the end of November I went shopping to Zoo Zajac in Germany together with Joeri, Stijn and Gert. My first aim was to explore this huge store and buy a complete JBL 2x54W Ultraduo T5 bar for 180 Euro. I almost bought it, but while looking at these bars, we discussed the possibility of buying separate components and build such a bar on our own. Gert and Joeri also needed new T5 lightning systems for their tanks, and they were more determined than I was at first, but the idea of writing a DIY article for MCH made me smile and decide to make my own light bar! Of course I had some doubts, but I set my technical mind to work and soon I figured out how to do it! I still had a 2x36W electronic High Frequency T8 (previous TL-D) ballast lying around so I skipped the T5 option. Obviously the build is exactly the same for T5 and T8 except the specific ballast and the IP67 lamp sockets needed for each type and provided we use an electronic unit for the T8 bar so no additional starters are needed. Here is my report:

Collecting the materials was relatively easy. The IP67 T8 lamp sockets were bought at Zoo Zajac. I already had the ballast at home, and the wiring and other small stuff was bought in a DIY shop. The only missing element was a 50mm x 50mm bar that could be sealed on both ends to make it 100% waterproof. I asked for information in many shops, but none of them could deliver exactly what I wanted. I almost gave up, but the solution was closer to my home than I first thought! I went to the local welder that already made the stainless steel frame for my 1500L kitchen tank before. He indeed had a 50mm X 50mm bar and the best thing had yet to come: it was stainless steel and the matching sealing plugs were also in stock! The only downside was the thickness of the metal which made the bar extremely heavy and the drilling a real pain!

Used materials list    Cost
(1) Bar: 50mm x 50mm bar cut to length    13 Euro
(2) Ballast: electronic 2X36TL-D (T8)    35 Euro

(3) T8 lamp sockets (IP67)   

14 Euro
(4) Plastic sealing plugs     included with bar
(5) Wiring, M4 bolts and thread, polymer glue (not shown)    18 Euro
TOTAL:    80 Euro

The Philips electronic TL-D (or T-8) ballast

Very convenient: the connection circuit for the lamps printed on the ballast.

The plastic sealing plugs made the final assembly step extremely easy!

Time to assemble the separate components into a working light bar! Measuring the lamp with the IP67 sockets attached to it was the first thing to do. I made the drill markings on the bar and started drilling. The welder had warned me before that stainless steel is a very hard material, so I "thought" that I was prepared for this tough job. Very much patience and sloooow drilling was needed to do this. In the end I would have been better off with taking this bar to my dad who has a drill press to get a more accurate result, but still many hours later and after much swearing and cursing at that "damned" bar I managed to finish this task!

Now I could start the real assembly! Soon I found out that I made a small mistake though, as I squeezed the lamp too tight into the sockets, what resulted it really tight fit. This doesn't affect the lamp as it's strong enough on it's length axis, but the future replacement of it will be a bit problematical. I will have to be very careful not to break the bulbs when replacing them with new ones. Anyhow I'm warned now to keep some margin the next time I'm going to make such a bar (I still have two 2x58W HF ballasts waiting for this)

Let's forget about the drilling as soon as possible!
2mm of stainless steel can be your worst enemy at times and really asks for a drill press instead of a clumsy power tool!!!

The further assembly went smoothly. First I had to pre-wire the IP67 lamp sockets which was relatively easy. I only needed to unscrew the socket and carefully remove the inner part with a small screwdriver. Then the tips of the electric wire were stripped and tinned and lead through the outer holes of the socket and connected to the inner contact mechanism. Then the wire was cut at a length that was long enough to allow me to have some margin when I had to connect them to the ballast in the final assembly stage. The wire tips at the other end were also stripped and tinned. Of course I had to repeat this until all 4 were ready. Then the metal threads were screwed into the sockets. This was the main problem that I was thinking about before I started the project. I was thinking of how I should mount the sockets onto the bar with the plastic bolts that came along with them. This would be far from easy, as the holes would be barely reachable from the outside. I could use a screwdriver through the opposite holes to mount the first set of sockets, but this was no solution for the second set. Drilling new holes for the opposite sockets was also out of the question for me. Then I was thinking about shorter metal bolts that could be tightened with a wrench instead of a screwdriver and a sufficient amount of washers to make it fit, but all of a sudden I got the idea of the short metal thread pieces! BINGO! This allowed a very strong connection, as the metal thread could be completely screwed into the socket. Then the wired sockets with the threads and the rubber joints were put on the bar with the wire going in first. On the inside a washer was placed and then the nut was screwed on the thread with a metric wrench (size 7) so the socket was attached really tight. The very last socket was screwed on after connecting the ballast and putting it in place in the middle of the bar.

The lamp socket ready to be wired.

I carefully removed the inner contact mechanism of the socket with a small screwdriver.

The wire tips were tinned and lead through the outer holes before attaching to the inner contact mechanism of the socket.

The wire connected to the inner contact mechanism.

The inner contact mechanism mounted again.

The key to my success!! A piece of short M4 thread and matching nut replaced the plastic bolt.

The thread and nut and my wrench to attach the socket to the bar. An additional washer was also used on the inside of the bar.
FYI the plastic bolt was removed!

 I only needed to be very careful to mount everything in the right order, as the ballast could not be placed into the bar with all the sockets screwed on. When all the wires were connected, the sockets mounted and everything double checked and properly earthed it was time to finally test the bar. Of course I took great care during the construction, and this was immediately rewarded as the lights went on without a single hesitation! I shook with the bar to be sure there were no flaky connections, but the lamps stayed on... YES!!! Now I could stuff the wires into the bar but chose to do it in a more tidy way what was not very easy though. In the end this doesn't really matter as after the final installation the bar won't move anymore. Then two stainless steel plates were mounted on each end of the bar for easy ceiling mounting. I've put a bit of polymer glue between the bar and the two plates to be sure that all gaps were filled so no humidity would be able to enter the bar and harm the electronics. One plastic plug with some polymer glue for additional sealing was pushed into the bar. Then the other plug was drilled so the electrical cable fitted tightly to ensure a good sealing. Then the wires and earth were connected again and this plug was also pushed into the bar. READY!!!

The first lamp mounted: this is starting to look good!

The last testing phase... YES it works!!!

The wires carefully hidden in the bar. It's not easy to avoid a messy cable spaghetti!

A 100% crop from the previous picture shows the holes on top of the bar for connecting another stainless steel plate for easy wall or ceiling mounting. There is also the possibility to mount a hook on each side of the bar for pendant mounting.

The next job was putting the construction against the ceiling of the 1500L kitchen tank. This was again tougher than I thought at first. There were no helping hands around and the kids were looking at me through the glass of the tank with a very nice smile. A failure was not permitted in front of my young audience but cursing and swearing all the more. With one hand I needed to hold the heavy bar and the other hand was needed to operate the power drill. I managed to fix the "damned" bar with 4 screws. Then I assembled the matching reflectors and fitted them onto the lamps, and after I stepped out of the tank again I've put the electric cord into my aquarium timer socket and shouted LIGHTS PLEASE!!! Great was my joy that everything worked as intended.

The twin light bar with additional reflectors mounted to the ceiling of the 1500L kitchen tank!


 Some people probably won't bother about saving 100 Euro but I hope that for the ones who do care, this article can be of great help. At least for me it was a very worthy project as I saved about 130 Euro because of the electronic ballast that I already had. Also remember that this report is applicable for both T8 (= TL-D) and the newer T5 systems, provided that the right lamp sockets and ballasts are used. If you think you're a skilled DIY aquarist and want to give it a try please do so. After all you can always share your experiences with the MCH team!

Note: "IP67" is an Ingress Protection (IP) Rating developed by the European Committee for Electro Technical Standardization.
IP67 means that the protection level that is offered. 6 = Totally protected from dust. 7 = Protected from the effects of immersion between 15cm and 1m

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