# Possible to run 24/7 without algae?



## slythy (Sep 1, 2015)

What size tank? 

On my 40B I did 24/7 without much issues with putting a peice of screen door mesh over the lights to try and dim it a bit. Now I have 180g with a single ( really 2 36" but with a 72" tank) and dont have much algae issues. I also ran excel too.


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## leejo (May 6, 2014)

slythy said:


> ...screen door mesh over the lights to try and dim it a bit.


That's a cool idea. It's a 29g, 30"x12"x18".

Thanks.


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## slythy (Sep 1, 2015)

leejo said:


> That's a cool idea. It's a 29g, 30"x12"x18".
> 
> Thanks.


yea it seemed to be bright on my 40b so I imagine its High light on yours.


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## MtAnimals (May 17, 2015)

It's my personal belief that the blue "moonlight" feeds the algae.When you run this light on a timer to provide darkness from 10pm to 6 am,the rest of the 24/7 cycle is still the same.Don't marine tanks use actinic blue lights to promote certain algae?

I used to have algae in my 55 with this light,since I put it on a timer,none at all.I have one on a 20 gal high with no issues running the same way.What looks bright to us isn't necessarily promoting algae.An old florescent bulb will grow algae like nobody's business,but look dim to us.


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## ustabefast (Jan 24, 2017)

I don't think it's the 24/7 mode that's creating the algae, I think it's that you are using two of these fixtures on a tank that may do fine with just one. 
These fixtures only provide usable brightness for plants for a few hours a day, so the much reduced lighting they produce in mornings and evenings should not be a big deal.
You will need lots of plants and a well dialed in fert regime to avoid algae issues using two of these.


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## Immortal1 (Feb 18, 2015)

Have to agree with Ustabefast - too much light with 2 fixtures. I would suggest trying 1 fixture in 24/7 mode assuming you have enough plants and ferts to support the single light.


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## leejo (May 6, 2014)

OK thanks. You think one is enough to have everything carpet well?


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## natemcnutty (May 26, 2016)

leejo said:


> OK thanks. You think one is enough to have everything carpet well?


Depends. Thanks to @clownplanted, we know that the 24/7 is around 50 PAR in the 16-18" depth range. In the 24/7 cycle, you really don't get that long at that PAR.

If you want the best of both worlds, set one fixture on a timer, dim it to whatever PAR level you need, and run it alongside the other fixture in 24/7 mode. 

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## sdwindansea (Oct 28, 2016)

I'm going to partially hi-jack this thread (sorry). Has anyone run CO2 with the 24/7 mode? It appears like the light truly starts to ramp up at 9 AM and down at 6 PM. Would it be safe to assume you would want the CO2 to start around 8 AM and off at 5 PM? I've searched around a lot on this one but never really found any kind of answer.


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## clownplanted (Mar 3, 2017)

sdwindansea said:


> I'm going to partially hi-jack this thread (sorry). Has anyone run CO2 with the 24/7 mode? It appears like the light truly starts to ramp up at 9 AM and down at 6 PM. Would it be safe to assume you would want the CO2 to start around 8 AM and off at 5 PM? I've searched around a lot on this one but never really found any kind of answer.




You really get about 5 hours of high light in 24/7 mode. You only hit max at 3pm. The other times are significantly lower. Check mattinmd thread he did. He did a full review and showed the par at the different times. I did par readings at max setting. With running two fixtures you will be getting between 90-100 par at 16-18" on max or 3pm time in 24/7 mode. That is too much par for low/medium light plants even at substrate.

3pm is when the light is at max and starts to really drop off after that. You are at about half par at about 4:30pm(24/7 mode) to give you an idea. I would turn off co2 at around 4pm if running in 24/7. I run mine on max for 10 hours a day. Turn on co2 at 7. Light on max at 8. Turn off co2 off at 5 and max light off at 6. Should probably run co2 not as long but hey it works for me. 

The reason I am not running in 24/7 is because I am using only one fixture on my 24" deep tank. Where from substrate to light is 23". I get low 40's par at max setting that far down and even high 30's when offset further from center. Works great though for my low/medium light plants. All grow very good with my co2 and light. 

Here is my par/lux/kelvin/pur readings at different depths if interested

Finnex 24/7 Planted PAR/LUX/Kelvin/PUR readings http://www.plantedtank.net/forums/1...24-7-planted-par-lux-kelvin-pur-readings.html
link to Mattinmd post he did doing the full review of the 24/7 with par readings at the different times. Very good stuff http://www.plantedtank.net/forums/10-lighting/871385-finnex-24-7-full-review.html


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## natemcnutty (May 26, 2016)

sdwindansea said:


> I'm going to partially hi-jack this thread (sorry). Has anyone run CO2 with the 24/7 mode? It appears like the light truly starts to ramp up at 9 AM and down at 6 PM. Would it be safe to assume you would want the CO2 to start around 8 AM and off at 5 PM? I've searched around a lot on this one but never really found any kind of answer.


I do on my 20 gallon long (10" to substrate) because my wife hates using it any other way. Currently, I have CO2 come on at 8 and end at 4, and it usually gasses off over the next couple of hours. I run 2 HOB's, but I also use a lid.

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## sdwindansea (Oct 28, 2016)

Thanks @clownplanted, I was actually basing my post on the measurements of PAR over time from mattinmd. I've just converted over to CO2 a couple weeks ago and I have the light set to about 80% white/red for 8 hours per day (CO2 on/off an hour before lights are on/off). I have a shallow tank (48" x 15" x 17") so the lights are about 14.5" off the substrate.

Thanks @natemcnutty, that is pretty much exactly what I needed to know. I'm still not sure if I'm going to utilize the 24/7 mode yet. If I do it will be off from 10 PM - 6 AM.


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