Lighting Requirements for 125 gallon Planted Aquarium
Hi All! I have a 125 gallon aquarium (72" long x 18" wide x 24" depth) and I'm trying to figure out the best and cheapest solution to light it. Right now I have 4 T8, 30 watt bulbs but I know that's not enough as I need a minimum of 2 watts per gallon. My plants I have are growing slowly but I'm having a few issues... Any suggestions on the best approach for lighting other than spending a fortune on a new ballast? Has anyone converted a T8 ballast to a T5? And will that get me enough wattage?
Thanks in advance for any help you can offer.
First, may I welcome you to Tropical Fish Keeping forum. Nice to have you.
Now to your question. The "watts per gallon" so-called "rule" is something to forget. Plants need far less light than many will tell you. I have less than 1 watt per gallon on all but one tank, and I have no trouble growing plants as the photos under "Aquariums" below my name on the left illustrate.
However, you must decide on a few things in order to have success. First, what sort of planted tank are you expecting? And with this, what sort of paraphernalia do you want to spend all your money on?;-)
My tanks are quite low-tech, natural systems. Minimal light (sufficient to allow the plants to photosynthesize) out of deference for the fish, and added liquid fertilizer to balance. On my 115g which is 5 feet, I have two 48-inch T8 tubes, amounting to 80 watts (more or less, some tubes use less watts to provide equal intensity). If your present tubes extend full length, or nearly, in a double parallel row, you're probably fine. You may have to change the tubes, I don't know what spectrum and kelvin you have; we can discuss this later.
T8 and T5 are not compatible; you would be better buying a new fixture. However, I would not. I had a T5 dual-tube with two 48-inch HO tubes over my 115g last year, and after one week I took it back for a T8 dual-tube. It was far too much light. If you had NO tubes, it would work, but as they are basically equal to T8 the added expense seems pointless.
Hope this gives a bit of help. You might want to have a read of my article "A Basic Approach to the Natural Planted Aquarium" in 4 parts at the head of this section of the forum. A general background to how all this works, with the photos of my tanks showing the expected results.
Welcome to TFK, desico. We are glad you joined us! The four part sticky that Byron wrote up has alot of good info as far as understanding planted tanks. Looking forward to following along with your progress! :-)
Thanks for the info Byron...
The more I read the more confused I get :(
OK - here's my tanks issues/status...
As I said, it's a 125gallon tank
My last test results (Feb 20th)
KH: thru the roof? It was high - didn't write it down.
I run 2 Aqua Clear 110 power filters but I'm changing one out for a canister
My lighting is 4 T8 30watt fluorescents (32 inches long each I think), I also have sunlight - I usually have the lights on for about 12 hours.
Since my testing I've added a DIY C02 system which is giving me about 1bps
I was dosing with Flourish twice a week - I've since changed that to daily (divided the weekly dose by 7)
I dose twice a week with Flourish Nitrogen and Phosphorus
I do 30 - 50% weekly water changes.
My sword plants are about 2 weeks in the tank now and are starting to go downhill - black around the edges a little, brown/yellowing leaves, the leaves are kind of 'crispy' to touch. Most of my plants have the black along their edges and from another post I read here I think it might be black algae?? The rocks are also covered in black stuff - it's flat tho so it's not brush algae - unless my flying fox is eating it before it can gro?
Things are looking slightly better since adding the CO2 but the plants are still struggling and I'm just getting more frustrated....
Thanks 'aunt kymmie' - should at least give you a laugh or two :)
Plants need red and blue light to photosynthesize. Tubes that are high in red and blue (the spectrum graph) will provide this. But such tubes (the so-called Aquarium/Plant tubes like "Aqua-Glo", "Flora-Gro" and similar names) are almost always weaker intensity (the lumens), so you lose here too. Full spectrum and cool white tubes that have a good red and blue output but balanced with green (which gives a natural rendition of fish and plant colours) are the best. I can go into this more if you need; perhaps you could tell me the name and kelvin rating of the tubes you are using now.
The "black" is almost certainly algae. This frequently occurs when light and nutrients are out of balance for the plants; in balance the plants out-compete the algae, but as soon as something is missing and the plants can no longer photosynthesize fully, algae takes advantage.
The yellowing is a nutrient/light issue we can solve when I have the afore-mentioned information.
ok - I have 2 Power Glo bulbs that are 18000k, 30W and 2 Eclipse Natural Daylight (not sure of the lumens)
I should replace them all since it's been a while - what do you suggest?
If they are T8 tubes, they should be good for a year. Some suggest longer, up to 3 years. I am up to 18 months with some of mine and am thinking I may need to replace them.
To the tubes you have. The Natural Daylight should be OK, especially when combined with the Power-Glo which is more blue. Eclipse is said to be 6500K. I use the Life-Glo 2 which is 6700K as one tube, and then for the second I have been using a cooler "blue" type.
I think I'm going to replace them all and see what happens - especially since you say I have more watts per gallon than you do...
Thanks for your help - I'll keep you posted :)
Hi Byron! Thought I'd give you an update on my tank. I changed out all my bulbs (holy cow I didn't realize the old ones were so dull!!!) and things are going well. The black algae has stopped spreading and everything is starting to perk up. Then... my light hood dies. The switch went on me quite a while back so I was just using the plug but then it stopped coming on at all. Figured it was time for a new hood. I bought a coralife hood that has compact florescents - gives me a little more wattage.
Anyway - things are going good and all my plants and fish seem to be happy. I've seen some really good growth on my plants since changing my bulbs and lots of bubbles on them (I read somewhere that the bubbles are the plants giving off oxygen as they photosynthesize - not sure if that's true but I hope it is!).
Thanks for all your help!
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