# Will dropping photoperiod help fight green hair algae?



## butchblack (Oct 25, 2019)

Hi

I'm starting to get some green hair algae and slightly green water in my 20L tank. I have 7 juvenile corys? I'm currently running the light 8 hours a day. I just reset the timer for 4 hours a day. Should that help? The only plants I have in that tank are some java moss. Will 4 hours a day be enough light for them? Light is a Nicrew LED. Corys are happy and are growing, so I don't want to upset things too much.


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## Surf (Jun 13, 2017)

In my experience green hair algae has only appeared when there is a nutrient deficiency. Plants cannot grow when there is a nutrient deficiency. But somehow Algae can still get enough to grow. In my experience When the nutrient deficiency is corrected the hair algae typically melts away rather quickly. 

So in one sense it is easy to eliminate it, just identify the deficiency and it goes away. But there are 14 nutrients that are essential for plants. If you are short on any one nutrient you can have hair algae/ it can be difficult to nearly impossible to identify the missing nutrient causing the problem. Some are easy like zero nitrate (i should never be zero if you want healthy plants). But others can be very difficult. Recently I had to get a lab test done to identify a deficiency and it ended up being a manganese and Chloride deficiency. Once I had the report I correct the deficiencies and it took about a week for all the hair algae to die off. in my opinion most types of algae benefit from nutrient deficiencies.

I have never found light levels to be effective against hair algae in my tank. But the one time I had green water it did have an effect and the water cleared. But I was using dimmer and it didn't take much of a reduction for the water to clear. As I recall it only took a 20% reduction in light output to do the job. my lights were on 6 hours a day before and after dimming the lights. I would be concerned that 4 hours a day would not be enough for light for your plants. 

Not using a fertilizer and not doing once a week water change is frequently a very good way to trigger hair algae problem.


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## Asteroid (Jul 26, 2018)

If all you have in your tank is java moss and you've run a full cycle (8 hrs a day) from the getgo it's most likely light that is causing the problem. Java moss is very undemanding and doesn't require much in terms of ferts to grow. 

In most cases it's the imbalance of light and organic load that will cause almost all algae. People manage tanks that have no plants without algae so the common denominator can't be nutrient deficiency. What they all have in common is light and organics. 

For your situation, reduce the light to the 4 hrs (plenty for java moss), increase water changes and put carbon in the filter. The water changes and carbon will reduce the organic load in the tank. Reducing the light will decrease the growth so the tank can catch up.


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## butchblack (Oct 25, 2019)

Asteroid said:


> If all you have in your tank is java moss and you've run a full cycle (8 hrs a day) from the getgo it's most likely light that is causing the problem. Java moss is very undemanding and doesn't require much in terms of ferts to grow.
> 
> In most cases, it's the imbalance of light and organic load that will cause almost all algae. People manage tanks that have no plants without algae so the common denominator can't be nutrient deficiency. What they all have in common are light and organics.
> 
> For your situation, reduce the light to the 4 hrs (plenty for java moss), increase water changes and put carbon in the filter. The water changes and carbon will reduce the organic load in the tank. Reducing the light will decrease the growth so the tank can catch up.


Thanks. From what I've read it sounded like my best plan of action. I added carbon a couple of days ago, and am doing daily or every other day water changes. We'll see how well it works. How much organic load can 7 juvenile corys produce? Although, they're growing rapidly, so I'm assuming I'm feeding them well. 1/8t nano bites 2X day, occasionally substituting FD bloodworms or an algae wafer.


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## Deanna (Feb 15, 2017)

I agree with the above, for the most part: hair algae develops more easily when things are out of balance, e.g.; too many organics or nutrient issues (including CO2). However, to answer your question, light can play a large role in exacerbating any of these imbalances.

I would follow the paths mentioned by @Surf and @Asteroid: reduce light and get cleaning, feeding and nutrients under control. When plants are healthy and algae is down, start increasing light again, but keep in mind that changes in light levels may also require adjustments in nutrient levels. You might also try the "siesta" concept. This is allowing for 2-3 hours of lights on, separated by 2-3 hours of lights off. Algae benefits from having consistent light for 4 hours or so and interrupting that, has been shown to help.

Also, dosing products such as Excel will not only help plants, but can kill hair algae at high doses. However, this statement is only for the benefit of others that may be having hair algae problems. Excel-type products can harm 'moss' that we use in aquariums. Another effective algae killer are products that contain certain surfactants, such as AlgaeFix, but use these carefully and, IMO, administer at half the recommended dose, but twice per day.


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## LuluCocoPopoRoro (Feb 20, 2019)

I am having a similar problem.

I have my light on from 10am to 9:10 pm. I know that’s really long, but until know my plants have been doing well.

Will reducing the lighting to 5-6 hours, will this kill off my plants. They still will get ambient light from the room


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## DaveKS (Apr 2, 2019)

Simplest solution would be put dimmer on light and also install a colony of floaters. Floaters will steal algae’s energy source (light) and also clean tanks water of excess organics. 

Moss will never be able to outcompete algae. Even those cheap nicrew light are to bright for that shallow a tank with only moss in it.

You’ve got mingdak dimmer which works for those nicrew lights, just cut it down to around 60% max.


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## LuluCocoPopoRoro (Feb 20, 2019)

DaveKS said:


> Simplest solution would be put dimmer on light and also install a colony of floaters. Floaters will steal algae’s energy source (light) and also clean tanks water of excess organics.
> 
> Moss will never be able to outcompete algae. Even those cheap nicrew light are to bright for that shallow a tank with only moss in it.
> 
> You’ve got mingdak dimmer which works for those nicrew lights, just cut it down to around 60% max.


Will changing the lighting drastically harm any of the existing plants?


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## DaveKS (Apr 2, 2019)

LuluCocoPopoRoro said:


> Will changing the lighting drastically harm any of the existing plants?


Have no idea what plants you have so can’t answer that. You should really start your own thread with pics of your tank, tank/light/water/livestock specs if you want meaningful help instead piggybacking on this other posters thread.


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## LuluCocoPopoRoro (Feb 20, 2019)

I was going to do that originally, but I thought if I did, I’d be told it too similar to this one.

I’ll start one, thanks


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## butchblack (Oct 25, 2019)

DaveKS said:


> Simplest solution would be put dimmer on light and also install a colony of floaters. Floaters will steal algae’s energy source (light) and also clean tanks water of excess organics.
> 
> Moss will never be able to outcompete algae. Even those cheap nicrew light are to bright for that shallow a tank with only moss in it.
> 
> You’ve got mingdak dimmer which works for those nicrew lights, just cut it down to around 60% max.


Unfortunately, I have never been able to get the Mindak dimmer to work properly, so I've given up on it. It's on a timer. I cut the duration from 8 hrs straight, to2 3 hour periods with a 2 hour break. I just cut it further to 2 2 hour periods with a 4 hour break and I'm going to step up water changes to 3x a week.


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## DaveKS (Apr 2, 2019)

butchblack said:


> Unfortunately, I have never been able to get the Mindak dimmer to work properly, so I've given up on it. It's on a timer. I cut the duration from 8 hrs straight, to2 3 hour periods with a 2 hour break. I just cut it further to 2 2 hour periods with a 4 hour break and I'm going to step up water changes to 3x a week.


Well remember your thread about not working in your photo light but as Jeff figured out it design of that light having constant current driver and no way to control it after driver. 

If you manually turn mndak dimmer on it overrides all step programming and will just stay on at 100% till you turn it off. 

I use 2 nicrew lights and both have mingdak ramp timers on them. Comes on, ramps up to 20%, 1hr later ramps up to 45%, 3hrs later ramps up 85% and stays there for 4hr then ramps back down to 40%, then 20% 3hrs later and then off 1hr later. 

You might have got a lemon I guess. 

You could always just run a manual dimmer also. Most you’d probably need with a 8hr light cycle doing just moss is about 50% intensity. 

https://www.amazon.com/NICREW-Aquar...ocphy=9024238&hvtargid=pla-617264952147&psc=1


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