Lighting requirements for CO2 tank

[johnjo]

Setting up my first CO2 tank at the weekend and now its the turn of getting the lighting right!
Tank will hold approx 30L and have CO2 injection.
Mixed bag of new Tropica Easy, medium, advanced plants plus some existing anubias and crypts to go in there with Tropica Soil
The light I will be using is an ONF Flat Nano rated at 15w
There us a guy online who has done a par rating for this lamp and I have attached this for reference. Im not sure where to start with par ratings now we are on LED's. It was easy to get an idea with flourescants and watts!!

My question is as the plants will mostly be juvenile and small should I reduce the lighting to 50% say, until they take root and start growing properly, maybe observe for a week or two and then adjust as I go along. High energy aquariums are new to me and I don't want to ruin the tank before I have even got going with a massive algie outbreak if I can help it.

 

[John q]

Mixed bag of new Tropica Easy, medium, advanced plants plus some existing anubias and crypts

My question is as the plants will mostly be juvenile and small should I reduce the lighting to 50%

A lot depends on how far away the light is from the plants, but... assuming it's 12" to the substrate they'll be getting 90 par directly underneath the light, which is a lot for a new set up. Halving it to 50% is still going to give you plenty of light, maybe even to much, but it's a fair starting point.
The established anubias and Cryptocoryne will manage fine with much lower light than this, and the freshly submerged new plants will thank you for a week or two of dimmed light.

Try it at 50% and see how it goes, far, far easier to up the % at a later date than to go in all guns blazing and melt the new plants.

 

[Andy Pierce]

I have a 40L tank with a 15W Kessil A80 'tuna sun' LED light. Here is my daily lighting sequence (Aquarium lighting - Fireplace aquarium)

Timing	Description
00:00 – 09:00	lights off
09:00 – 10:00	5% intensity, 0% colour
10:00 – 11:30	ramp up intensity and colour
11:30 – 14:00	70% intensity, 80% colour
14:00 – 17:00	ramp down intensity and colour
17:00 – 18:00	5% intensity, 0% colour
18:00 – 00:00	lights off

The tank is taller than it is wide though so there is some depth the light has to go through to penetrate to down to the substrate floor which might be different to your setup. For algae control I find it is more useful to limit the peak intensity of the light than it is to limit the duration of the light. I have 2 hours of low intensity light on the front and back which keeps the aquarium lit up for me to see and enjoy the view for longer (humans are really good at perceiving low light levels) even though I don't think that does much for either plants or algae growth. I'm with @John q that you're much better served starting with lower light and increasing than going in with too much light and trying to fix it after it causes all manner of problems (do a forum search for 'photon cannon').

 

[johnjo]

Thanks for that, great advice as always. Iv had the light for a while but my set up has been low light no co2 so Iv only been running it at 30%. I’ll give it a go at 50% and see how the plants respond, hopefully less chance of any bad algie outbreaks!