# Decreasing Algae and Maximizing Plant Growth



## Calico7 (Dec 7, 2016)

I had to leave my tank unattended for 3 weeks without water changes, CO2, or liquid fertilizers. My light was set on a timer to stay on for 6 hours each day. When I returned, my tank and plants were covered in algae. I scrubbed the whole tank, but there wasn't much I could do for the plants. 

It has been a few months since the algae massacre, and my plants are growing new healthy leaves. My problem now is that the new growth is also accumulating little bits of algae. My plan was to let the plants grow out enough that I could cut away the bottom algae infested parts and replant the new healthy stems. I can't do that if algae continues to grow on the leaves. How can I stop the algae from growing on my plants?

*Tank size:* 20 gallon tall
*Lighting:* Finnex Planted 24/7
*Photoperiod:* 5.5 hours
*CO2:* 1 bps
*Fertilizers:*
- Nutrient rich substrate
- Flourish root tabs, placed every few months
- Flourish, 2x/week
- Excel, 4-5x/week
- Iron, 4-5x/week
- Potassium, 3x/week 
*Plants:* Ammania gracilis, green ozelot, anubias, amazon sword, alternanthera reineckii mini

Right now the tank is moderately planted, but I would eventually like to heavily plant it.


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## phopf (Dec 17, 2016)

Discard as much of the affected leaves as possible. For your stem plants, trim the upper inch or so, throw out the bottoms, and replant. For the swords, discard all but the best few leaves. Put some fluorish excel (or home made glutaraldehyde solution) into a spray bottle (I used an old glasses cleaner bottle myself). Pull out the plants (what is left after your intense trimming efforts) and spray them down with the flourish excel. Let them sit out of water for a few minutes, then put them back in. For stem plants replant the ends that you had pruned off. 

I would then do a good 50% or more water change. Keep track of how much volume of fluorish you introduced. I would do a bigger water change if it looks like you will be left with an excess amount.

If you have an inline UV light you might consider running it for a while to kill off lingering spores.

I had a similar problem when I bought an established tank. I had to repeat the above once to get things cleaned up, but there should be no harm to the species you are listing. Finally, just to be clear, you will want to have your fish out of the tank until after the water change.


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## Calico7 (Dec 7, 2016)

phopf said:


> Discard as much of the affected leaves as possible. For your stem plants, trim the upper inch or so, throw out the bottoms, and replant. For the swords, discard all but the best few leaves. Put some fluorish excel (or home made glutaraldehyde solution) into a spray bottle (I used an old glasses cleaner bottle myself). Pull out the plants (what is left after your intense trimming efforts) and spray them down with the flourish excel. Let them sit out of water for a few minutes, then put them back in. For stem plants replant the ends that you had pruned off.
> 
> I would then do a good 50% or more water change. Keep track of how much volume of fluorish you introduced. I would do a bigger water change if it looks like you will be left with an excess amount.
> 
> ...


Thank you for the suggestions! I'll definitely be trying them out. Isn't it true that adding more plants can decrease algae because there are less excess nutrients to promote algae growth? I've also heard that increasing CO2 levels can kill off algae, but I believe I've also heard it can do the opposite.


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## phopf (Dec 17, 2016)

+1 to Funken_A

One thought on the whole tank peroxide/glutaraldehyde treatment: go for it if you prefer. I suggested spraying your plants because realistically you need to be doing some very significant pruning. Even if the algae on leaves/stems dies off, the affected areas never really recover. You are better off promoting new growth.

I should have completed my post - in addition to the clean up phase, you need to optimize your setup to avoid the problem in the future. And it sounds a lot like excess light, with limiting nutrients. Tom Barr has a great article on the dangers of over-lighting. The light limiting growth management method - Aquarium Plants - Barr Report. It is well worth reading.

Five and a half hours on a 24/7 is a lot of light without CO2 and fertilizing. The realistic choices you have are to drastically cut the lighting, or to add nutrients. It seems to me that the 24/7 can only be run on the default sunrise/sunset program or on manual, so you might need to either raise the light, or get an inline dimmer to reduce the intensity even during the photoperiod, if you want to go the route of restricting light. Going lower light is definitely much less work! (although I confess I do prefer the 'popping' look you get out of very high light, such that the tank is the brightest object in the room, and I am possibly too impatient to settle for a slower, more stable, and probably more ecologically sound and accurate low light setup.)


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## Calico7 (Dec 7, 2016)

phopf said:


> +1 to Funken_A
> 
> One thought on the whole tank peroxide/glutaraldehyde treatment: go for it if you prefer. I suggested spraying your plants because realistically you need to be doing some very significant pruning. Even if the algae on leaves/stems dies off, the affected areas never really recover. You are better off promoting new growth.
> 
> ...


I am using CO2 and ferts with the 5.5 hours of light. While I was gone for 3 weeks, I could do neither of these things and that is why the algae got so out of hand.


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## Calico7 (Dec 7, 2016)

I used the hydrogen peroxide method and sprayed plants with Excel. There is no longer algae on my plants, but the direct use of Excel had a very bad effect on my alternanthera reineckii. My green ozelot also has a few "burned" leaves but it grows new ones almost everyday so I am not as worried about it. The other plants seem to be fine. I would definitely recommend diluted the Excel with water, or avoid using the spray method for more sensitive plants. 

Here are pictures from right after treatment:




A few days later...


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