# Are my TMC grobeams giving me too much light?



## Reuben (17 Apr 2013)

Hello,

I have a 125L planted tank lit by two TMC grobeam 600 that are inside the hood 4cms above the water.   I have the lights on for 8hrs a day, setup with the controller they ramp up from 0% to a max of 50% power output.  The ramp period is set at 200 minutes -so jut a short period at max (50%) output sandwiched between ramp up and ramp down.

Can anyone help explain how much light this is?  Low, medium or high level?  I can always dim the max output some more if advisable?  I have good flow, high CO2 and ferts are E.I. on the generous side!

It is thanks to this site my tank is looking as good as it is, I just need a bit of advice to make sure I am not making life difficult by blasting light at the plants.

Thanks.


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## BIN578 (17 Apr 2013)

Thats quite a long photoperiod and that close its quite a lot of light to be honest.  One of the mods on here used to have two of those lights (now he has tile/s) but it was a lot higher and Im not sure if he capped the output as well.  How are yours suspended as TMC do the mountaray bracket which keepts it a nice height.  I would look at 6/7 hours esp if you want to stick with 100% output.


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## George Farmer (18 Apr 2013)

I'd say that's moderate lighting, certainly not excessive over 125 litres, especially with good CO2 and circulation.

Ian Holdich had a similar lighting configuration. Try contacting him.


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## Reuben (18 Apr 2013)

Thanks for the replies.  A moderate amount of light is what I am aiming for.  I recently lowered the amount of output from 70 to 50% as I had a problem with melt on L.aromatica - which I since tracked down to a drop in CO2 flow caused by my diffuser plate needing a clean!  That's all fixed and another lesson learned so just wanting a bit of advice to make sure the lighting is right.  Hopefully Ian will see this and advise.
Thanks


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## BIN578 (18 Apr 2013)

Reuben said:


> I recently lowered the amount of output from 70 to 50%


 
Doh ! I didn't read this bit, LOL.  That being the case, I concur its moderate hehe.  That is ALSO the beauty of TMC lights IMHO


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## Claire (19 Apr 2013)

Just watch the tank and it'll tell you if it's too much.


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## Reuben (20 Apr 2013)

Thanks.  But I suppose this; 





Claire said:


> Just watch the tank and it'll tell you if it's too much.


  could be said of any problem with any aspect of a setup.  The reason I'm looking to limit light is that I am under the impression this will create less of a demand for nutrients and CO2?  I'm led to think that these two components are more of a cause of plant health problems in aquariums?  I do have issues with my tank (bit of brown algae on some slow growing plants, and a bit of green algae on hardscape) but these are probably hangers on from before I got my act together with Ferts and CO2?  Or at least I hope so, hence the reason for trying to get another opinion on my light setup as most folk seem to talk about T5 or T8 lighting.  I'm hoping that with CO2 levels high, flow levels good and High EI dosing I might finally get the plant growth I have seen people on here getting...


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## Claire (20 Apr 2013)

Yes. Lower light will lower the plants needs for co2 and fertilisers, so it will be your limiting factor, if you like. I like to think of it as like balancing the scales between the 3. If everything is balanced then things go to plan - you get good growth and little to no algae growth, however if there is an imbalance then that's when things start going funny.
Too high fert concentrations can cause certain algae types, hence keeping up with water changes to "reset" levels is important. Too high co2 will obviously cause problems with any fish and too low or fluctuating co2 also leads to certain algaes. Too much light does the same.
Growth of your plants is limited by the lowest aspect of your lights, co2 and ferts.
I find that keeping the light down as the lowest aspect is the easiest way to start achieving the right balance as you can't really have too much co2 (unless you start gassing livestock...) and ferts are easily enough reset with water changes.
I hope this makes sense. It's been a long day...


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## Ian Holdich (22 Apr 2013)

I had the 500's over my 125ltr and had no problems at all growing anything. I did run c02 though. The par on the 600s is supposedly better than the 500s and going by the tiles I would edge my bets that they are a stronger light than the 500s. I ran mine at 100% all the time, with just a half hour ramp time. I was also using the mountarays, so they weren't adjusted. 

To answer your question, running them at 50% will be low light IMO. Running them at 100% would be edging on higher light. However, if you're growing what you want at 50% then leave it. If it looks like it works and it feels like it works, then it works.


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## Reuben (22 Apr 2013)

Thanks Ian.  I've been doing quite a bit of faffing with most things to get myself back on track.  When I set up the tank I bought a couple of books about how do it and followed the advice , it all went a bit wrong, then I found UKAPS .  Anyway now I am dosing EI, have good flow (a spraybar setup), and consistent high CO2 I might up the light some more. My plants are mostly doing well, but are not yet thriving away like some tanks I see on here, and I still have a tiny bit of algae here and there -not too bothered about that but do want the plants to be in full health. I will try upping it a bit.
Thanks


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