Question about light levels

[jonnythan]

I have a 20L that I'm going to be putting plants in. I've kept fish for a long time, but this will be my first try at plants.

I have 15 pounds of Flourite Black Sand I'm going to mix with 10-15 pounds of Estes "blend o river" gravel and possibly some local gravel.

Anyway, I ordered this Coralife double strip light that has two 18 watt T5 bulbs, which I understand gives me about 63 watts worth of T12 lighting. That's 3.2 wpg. The tank is 30x12x12.

Is this considered low, medium, or high lighting?

Also, with the plant substrate and lighting, I'll be thinking about some sort of super-simple CO2 injection into a small upturned cup or shot glass. I'm wary of adding anything unnecessarily unsightly or ungainly into the tank for CO2 purposes. Would this be "better than nothing"?

And do I have to worry much about supplements, or will some basic Flourish be sufficient?

 

[SpeedEuphoria]

Dont worry about "WPG" or the equivalent "WPG" or other confusion that resluts.

That light is just fine for your tank and will grow many plants. CO2 is more of a factor. So if you start with low to medium light plants they will do fine. If you jump into CO2 then you will need Ferts and should be able to grow most plants w/o issues

 

[jonnythan]

Do you think it's worth it pumping CO2 into, say, an overturned shot glass or similar? Very little water flow, but I'm using a can filter and can keep the surface relatively still.

 

[SpeedEuphoria]

What filter are you using or planning to use?

Your talking about DIY CO2 correct?

Personally If you going to use CO2 you will likely need ferts, although small amounts. So I would plan on that.

It comes down to your plans. If you dont want or plan to use ferts then I would not add CO2, well at 1st anyway. So plan as such with easy plants. Then if you fully stock your tank and have it running for a couple months, then you could consider using CO2 at lower levels and maybe not need ferts as the fish load will provide enough ferts for the plants.


On the CO2 into a shot glass, I think you would be better pumping it into the inlet of your filter as it will get dissolved better and then be distributed around the tank better

 

[jonnythan]

I'll be running a Hydor Prime 10.

The filter inlet sounds like a good idea, thanks.

 

[ingg]

36 watts, not 63. Under 2 wpg of T5 light. Not sure where the conversion to 63 is coming from, but I get what you are trying to say.

It'll run as a medium light tank I think. It would definitely benefit, and might need, carbon - the tank is small enough that doing it with Excel wouldn't be too expensive as you get your feet wet. Seachem's Flourish Excel is liquid carbon. I've personally never been a big fan of DIY CO2 after trying it - I didn't like having to change out the bottles all the time to struggle to keep consistent flows - but others make it work (work being the operative word here ).

The more light you have, the more you need to keep balance. You are going to have to keep some balance. Lots of light and no food for the plants means another plant form takes the light and uses it - algae.

Plants need NPK. Nitrates, Phosphates, Potassium. (They also need lots of traces, called micros, but the big three, the macros, are NPK). They also need carbon, it is the building block they use to grow with.

How much (NPK and CO2) depends on plant species. I could pack a 20 long with all slow growers, and it'd be easy, sort of the tank Euphoria is describing. I could also shove it full of stems of rotala and ludwigia, and the growth would require me to feed the plants (or else stunt the plants and encourage algae).

 

[jonnythan]

Various spreadsheets and discussions on the site say that 1 watt T5 light = 1.7 watts of T12 light.

Thanks for the info and advice.

 

[ingg]

Ahhh, didn't realize folks were trying to put it through a conversion. It is a good thought to try and do!

That is a bit of a misnomer on its own though, be careful of doing that. T5's can vary widely in actual light into the tank just from which fixture (reflectors) you are using. It does become frustrating trying to get a universal nomenclature that addresses all of the different lighting options nowadays!