Lighting for my 100 gallon tank

Aaron J Spetner

I've been researching ways to achieve affordable lighting for my 100 gallon (L: 130cm, W: 50cm, H: 60cm) tank. I've finally gotten my mystery snails and electric blue crayfish moved out to a different tank so I can start having plants that actually survive (and it's been a nice surprise to see that a few of my old plants have survived at the root level and are starting to poke through again!).

I recently (two weeks ago) installed a pressurized CO2 unit and planted a bunch of java ferns and an Amazon sword plant. The java ferns are doing okay, but I am not seeing much growth out of the swords. I am assuming this is because the 6 cheap ten-watt flood lights I have are not providing nearly enough spectrum or output. I would like to increase the light levels so I can grow a variety of plants that can take advantage of the CO2.

I am trying to figure out the best way of going about this in an affordable way. My aquarium currently just has a glass top - no real hood to speak of. So I was thinking to build a hood to fit on top of the glass and build into it light fixture housings. Here are the two bulb options I've considered:

  1. The local hardware store (Israel) sells Hyundai-brand (also GP, which the clerk said is just HyundaI under a different label) PAR38 T27 6500k CFL flood lamps. Would these provide the spectrum coverage that I need and if so, how do I figure out how many watts I want?
  2. I found this on ebay: - it appears that these are made of 3w LED bulbs with a 2:1 white:blue ratio. Is this something that looks appropriate, and if so how much white light wattage should I be shooting for?

Of course, any other options/ideas would be welcome!

Thanks!
 

TexasDomer

You don't need a hood - most lights will comfortably sit on top of the glass lid.

The 6500 K CFL flood lamps should work, but the second option does not seem to have the right temp lights.

Personally I'd invest in LEDs. They're more expensive upfront, but they are cheaper in the long run (more energy efficient, don't need to be replaced often). I really like the Finnex brand.
 

Aaron J Spetner

You don't need a hood - most lights will comfortably sit on top of the glass lid.

The 6500 K CFL flood lamps should work, but the second option does not seem to have the right temp lights.

Personally I'd invest in LEDs. They're more expensive upfront, but they are cheaper in the long run (more energy efficient, don't need to be replaced often). I really like the Finnex brand.

Thanks for the reply. I was actually looking at Finnex (although availability is limited here). If I did go with them based on the tank dimensions I mentioned in the original post, how could I go about determining which Finnex product to purchase (model / size / etc)?

EDIT: I don't think Finnex is really an option (unless the small ones are powerful enough). The one IsraelI site that I thought was selling them turned out to just be an Ebay aggregator and the shipping fees are just through the roof.
 

Aaron J Spetner

the second option does not seem to have the right temp lights.

Pardon my ignorance, but it says "Light Spectrum :blue 460~465nm; cold white 6500~12000K". What does that mean? I thought that was a good range.
 

TexasDomer

Pardon my ignorance, but it says "Light Spectrum :blue 460~465nm; cold white 6500~12000K". What does that mean? I thought that was a good range.

I must've missed that. I only saw the 12000 K. 6500 K is ideal for plants, but 5000 - 10000 K will grow them.

If Finnex turns out to be an option, the Planted Plus is a great light for growing plants.
 

Aaron J Spetner

I must've missed that. I only saw the 12000 K. 6500 K is ideal for plants, but 5000 - 10000 K will grow them.

If Finnex turns out to be an option, the Planted Plus is a great light for growing plants.

So based on that, would you change your statement on the ebay product?

Which size / how many finnex units would you recommend?
 

TexasDomer

No, I still personally wouldn't get it. It looks like it's mostly made for Saltwater tanks. I don't think it would grow plants well.

You could go with one 48" Finnex Planted Plus. That would put you in the low-medium light range. For the plants you have now, that'd be fine. You could put any low light plant and some medium light plants in there and be fine. If you want to go with medium-high light, add two 48" Finnex Planted Pluses.
 

Aaron J Spetner

Thanks. A Finnex 48" is going to cost about $300 shipped.

One thing I forgot to consider: until I added the six 10w LEDs I had relatively low algae growth, but once I added them I started to see rapid growth of furry hair-like algae all over the driftwood, rocks, and substrate. After removing the mystery snails and crayfish and adding the CO2 and the java ferns (all in the same day - a bit prior to that I added 20 MTS as well) it seems that the algae growth has slowed considerably (to which my wife snorts as everything is still covered in fur).

So my question is, if the current lights are supporting this algae growth, what does that say as to how they will support plant growth? I have only had the plants in for about two weeks, so should I maybe try letting them grow a bit with the current lights before investing in new lighting?
 

TexasDomer

Thanks. A Finnex 48" is going to cost about $300 shipped.

One thing I forgot to consider: until I added the six 10w LEDs I had relatively low algae growth, but once I added them I started to see rapid growth of furry hair-like algae all over the driftwood, rocks, and substrate. After removing the mystery snails and crayfish and adding the CO2 and the java ferns (all in the same day - a bit prior to that I added 20 MTS as well) it seems that the algae growth has slowed considerably (to which my wife snorts as everything is still covered in fur).

So my question is, if the current lights are supporting this algae growth, what does that say as to how they will support plant growth? I have only had the plants in for about two weeks, so should I maybe try letting them grow a bit with the current lights before investing in new lighting?

Yeah, I wouldn't spend that much. That's a lot! CFLs and LED bulbs in floodlights from the hardware store would work just fine.

Lights that grow algae won't necessarily grow plants well, but if your lights are in the 5000-10000 K range, I'd give it a few weeks to see how your plants cope before investing in a new light.
 

Aaron J Spetner

I'd give it a few weeks to see how your plants cope before investing in a new light.

I agree with you in principle, but my mouse-click finger disagrees and bought seven 50w (4500-5000 lumens each) led chips + drivers from China on Ebay. And my neighbor just told me about a great guy who does custom aluminum products. Looks like someone's building a new lighting system.


Oh yeah, I bought a 5 meter RGB led strip as well
 

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