# co2 with low light



## fz1ben (28 Jan 2015)

Hi guys

After a recent bad experience(gassing some prized fish) I was going to change my tank back to low tech but I've been thinking today and I'd like some advice and help please

my tank is a pretty standard 125l rectangle and I was going to set it up low light( a single tmc grobeam 600 ) I have spare about 6 inchs above the surface. Am I right thinking this is low light? 

I was going to use easy lowtech plants some crypts, hygro polysperma and echinodorus tenellus. will adding co2 in small amounts say only 1 bps be of benefit or will this cause algae?

I'm thinking that with small amounts of co2 and low light I could cut back on ferts and drop the flow a touch please correct me if I'm wrong.

I'm not after fast growth at all but would like an easy"ish" tank to look after with healthy plants and fish

thanks for taking the time to read this 
cheers.ben


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## ian_m (28 Jan 2015)

fz1ben said:


> 1 bps be of benefit or will this cause algae?


bps isn't really a measurement as a bubble for your tank is not the same size as mine. Also I might have better CO2 dissolving solution than you. I might have leaks and you not etc etc. However I have 1-2bps in 180l and get yellow drop checker and fish fine, so you might be OK.

The only way to determine if you are low CO2 is by pH drop or drop checker. A pH drop of 0.5 will give 8ppm CO2, my reading of this chart on this page.
http://tropica.com/en/guide/make-your-aquarium-a-success/fertiliser-and-co2/

Algae is not caused by CO2, but by either too much light (for the CO2 & ferts level you have) or fluctuating varying CO2.

The Grobeams are very powerful lights, so you would have to wind it right down to make your tank low tech.

The chart below gives PAR values for low light. This issue you have is how to determine the PAR values for your light.


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## fz1ben (28 Jan 2015)

thanks for the reply,yeah I understand that bps is different for everyone. So say even if I only had 8-10ppm(say no colour change in drop checker) of co2 it would still be advantage with low light? I'm not sure if measuring ph drop would work as I have hard water with kh around 12dgh.

I wasn't aware the grobeam where that strong..... my other option is the t5s in the standard hood but there really close to the surface and I can't raise them without them looking crap.

 So if I limit lighting I won't need 30 ppm of co2 to keep algae at bay?


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## EnderUK (28 Jan 2015)

Its a case of trial and error you wont know what level of CO2 you'll need to keep the light, nutrient, CO2 balanced. Reducing light will mean you don't need the full CO2. Best bet would to crank CO2 to max and lights to minimum then slowly over weeks months crank up the light to the point were issues start. Then lower it down a few notches.


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## john dory (28 Jan 2015)

I'm using a single 25w t8,with co2.i'm getting half a point ph drop,which seems to be enough atm.
I use tnc complete once a week after a 33%water change.


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## fz1ben (29 Jan 2015)

Did you notice much difference after adding the co2 mate?


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## john dory (29 Jan 2015)

tbh,i`m still getting to grips with it all.
i recently installed a full length spray bar across the back,and just last week i upgraded the filter.iv`e had co2 woes..and even now it`s still not quite right.(bubble counter keeps blowing off the needle valve)
however,everthing i`ve planted is growing and is 100% algae free,so if i can just nail the co2,i`m fairly optomistic.


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