View Full Version : what shoudl my light watt be
Chuck_T
06-13-2006, 1:30 AM
i ahve a 20 g tank with a 18 watt light about 5 differnt plants would be about 10 but cant seem to live longer than 2 months healthily not enough light also im battling bba i think
reiverix
06-13-2006, 7:46 AM
What types of plants are in there? How much plant mass do you have?
Ms.Bubbles
06-13-2006, 3:06 PM
A 20 gallon tank needs about 30 watts of light over it to grow most of the low-light plants, so you need to increase your lighting.
Also, hopefully, the plants you've got aren't medium or high-light plants, or else you will need to get much more lighting--more like 40-60 watts.
DaisyTattoo
06-13-2006, 3:27 PM
Not to hijack someones thread but how many watts do you need for low light plants in a 55g. I have 2 15 watt lights, obviously not enough, but what is the minimum I would have to have in order to grow some java moss and java fern?
Ms.Bubbles
06-13-2006, 3:45 PM
I would say you need about 80 watts of fluorescent lighting to grow low-light plants such as java moss/ fern over a 55 gallon.
Chuck_T
06-13-2006, 6:23 PM
i had cabombas they died i had one that looked like a monkey tree it died now i got some type of swrod lookin one and penny wort i think (its turnign red) and ludwigi (red one) and i got anubias they seem to be doin the best
debaric
06-15-2006, 9:55 PM
I would say you need about 80 watts of fluorescent lighting to grow low-light plants such as java moss/ fern over a 55 gallon.
you can grow java moss and java fern in less than 1 wpg. It wont die if you grow it in 0.5 wpg. It will just look like its not growing at all but it will stay good looking.
Ms.Bubbles
06-16-2006, 10:14 AM
you can grow java moss and java fern in less than 1 wpg. It wont die if you grow it in 0.5 wpg. It will just look like its not growing at all but it will stay good looking.
I wouldn't recommend that people try to grow plants at only .5 wpg. If you want your plants to actually GROW (not just survive without dying) 1.5 watts per gallon is a nice starting point IMO. It will be more than enough for the java moss, good for java ferns, and at this light level you can add any of the low-light plants later if you want to.
A 20 gallon tank needs about 30 watts of light over it to grow most of the low-light plants, so you need to increase your lighting.
Also, hopefully, the plants you've got aren't medium or high-light plants, or else you will need to get much more lighting--more like 40-60 watts.
My Hydro, Val, Anubias and Java moss are all flourishing in my 20g with a 15watt bulb over it...
I was having some real issues with my corkscrew val's but that was a macro-nutrient issue that I recently resolved. I've started getting feeders again and they stopped melting and i've even caught them pearling after a long day ...
(I had to start dosing Phospherous Sulfate from Gregwatson to correct my issues)
I also just introduced that hornwart or whatever the hell the bushy plant is and since adding it the thing has been flourishing at an alarming rate.
For a while I hit a little snag where things weren't growing all that fast but I added co2 and started dosing Excel and then everything really took off... My anubias has popped out a total of four leaves between the two of them.
I don't personally think 15watt is an issue for many low light plants :/
Ms.Bubbles
06-16-2006, 1:30 PM
1-2 watts per gallon is recommended for low light plants. Starting with only 1 watt per gallon is risky when you consider that fluorescent lighting decreases in strength over time. If plants are not doing well (as the original poster stated), I would insure that the appropriate amount of light is there to begin with, then fertilizers would be my next step.
In the case of the original poster, we can't even be sure that the plants in question are low-light ones. They may be much more demanding than 1-2 watts per gallon.
Chuck--Another point to consider is the length of time plants lights are on. 10-12 hours a day is recommended for good growth (12 hours max or algae can become a problem).
beatle
06-16-2006, 9:58 PM
I've bought a fair amount of plants from a local breeder. He has a heavily planted 75g with several species of plants. I've asked him about his lighting and frequency. He has 2 40w bulbs from Home Depot and they light the tank for 6 hours a day.
I just didn't much like the statement that you need above 30 watts in a 20 gallon to grow most low light plants because I haven't had too many problems with my plants and i've only got a 15 watt is all <333
Goatman
06-17-2006, 9:11 AM
Growing plants and what "plant tank people" consider growing plants are two different things. To tack on 1/4" of growth over a couple days is all fine and good, but can hardly be considered really growing a plant. Adequate lighting makes for a lot of growth when coupled with CO2 and nutrient levels being balanced, and to try to quantify that to someone who has never had it is very difficult. If you are making your plants grow with a 15W fluorescent over your 20L, that's cool. What people here are trying to say (I think) is that in order to make for a lot of lush green foliage with low-medium light plants you really need another 15W at a bare minimum. Just my thoughts.
John N.
06-18-2006, 1:46 AM
People can do them with limited wattage, but your selection of plants and growth is limited to Java Fern, Anubias, crypts.
A coralife 65 watt or better, a 55w ahsupply.com kit is perfect for acheiving a lush tank for a 20 gallon.
-John N.
Goatman
06-18-2006, 9:40 AM
If you have a drill and skil-saw you could easily put together a CF fixture with all the pieces coming from Home Depot. I did mine in about three hours. You'll need:
2 Porcelain Lightbulb Sockets (Electrical)
14' of "zipper" cord (Electrical)
2 E-Z Wire Plugs (Electrical)
2 27W Philips Daylight CF Bulbs (Lighting)
1 Strip Socket (Lighting)
1 Small Sheet of Plywood (Bldg. Materials)
1 1x4x8 Pine (Bldg. Materials)
Build a plywood/pine box, wire it with the 2 sockets, screw in the bulbs, plug it in. Use the strip socket as the switch and you're on your way. All said it cost me about $80 to put 108W over my 55, so it should cost about $40 to put 54W over your 20. If you're willing to put in a few hours they end up working wuite nice. Also, since you're not retrofitting your fluorescent hood, if you have a glass top on the tank you can add 15 additional watts by continuing to use your fluorescent hood as well. Just my thoughts.
Ms.Bubbles
06-18-2006, 11:27 AM
I just didn't much like the statement that you need above 30 watts in a 20 gallon to grow most low light plants because I haven't had too many problems with my plants and i've only got a 15 watt is all <333
You probably wouldn't require all the fertilizers & C02 that you do if you just gave your plants enough light to begin with. Growing plants in a low-light situation doesn't usually require ferts. C02 is nice when balanced with lighting, but is definitely not required. Low light plants = low maintenance.
Beatle-- Most aquarium plants come from tropical regions that get about 10 hours of sunlight per day (+ dawn & dusk light). To grow plants well, 10-12 hours of light per day is usually recommended, particularly if the plants are not doing well (as is the case here).
Unfortunately I do need ferts. My corkscrew vals started melting before I started weekly doses of potassium. My Anubias and hygro started growing like crazy when adding co2 :O
my tank had 0 nitrate so I was getting a lot of BGA =/
I suppose it depends on the low light plants you get, though :O