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Discussion Starter · #1 ·
I recently installed a CO2 injection setup on my tank, and immediately (as in, within a day or two) had a massive explosion of thread or string algae. Aside from the algae, the plants are doing wonderfully! I've noticed growth spurts on everything in the tank.



I've done a little bit of reading, and people seem to blame these kinds of algae outbreaks on too much lighting. I'm coming from saltwater, where the issue is always insufficient lighting, so it's entirely possible. I had 4 24W T5s (from an old reef setup) on this 10gallon system, but I've gone down to 2 in the hopes that this will reduce the algae.

I'm fine lowering light levels to combat algae, but I want to make sure I'm not slowing my plant growth at the same time. Are there any tips on how to do that?
 

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Discussion Starter · #3 ·
So if I understand you correctly the tank was running the 4x24 without the co2 initially?
That's right. It's a new tank, but it ran for about a month with those lights and without the CO2, with very little algae. Adding the co2 was definitely the catalyst for the algae bloom.
 

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If I understand correctly you need a balance of lights, CO2 and ferts. If any of the above are out of whack you get algae. Seems as if you have high light, CO2 and no ferts so the plants use what they need and then the algae takes the rest and runs with it. Definitely still a noob here but I think you need to either greatly reduce lighting or add ferts to achieve balance.
 

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Discussion Starter · #8 ·
Creekbottom: They're 24", 24W bulbs. I believe that's HO. I can't run a single bulb.

If I understand correctly you need a balance of lights, CO2 and ferts. If any of the above are out of whack you get algae. Seems as if you have high light, CO2 and no ferts so the plants use what they need and then the algae takes the rest and runs with it. Definitely still a noob here but I think you need to either greatly reduce lighting or add ferts to achieve balance.
That doesn't seem right to me. Light isn't something like a nutrient in the water that a plant can use some of, and algae gets the rest. The plants and the algae are seeing the same light level. It may be that there's some light level where the plants will survive and the algae can't, but it isn't a matter of (Total light) - (Amount used by plants) = (Light growing algae). I suspect adding fertilizer would cause an even greater algae explosion.

Does it make sense to throttle the CO2 back instead? My gut feeling is that I've eliminated CO2 as a factor limiting plant growth, so my main drivers are the nutrients in the water and the light. If the plants are able to outcompete algae at a lower CO2 level, maybe it's worth trying to find that level rather than reduce light. I'm worried I'm going to stunt plant growth if I throttle the light back too much.
 

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I'm fairly new at this as well, but I've had my fun battling algae and it's finally on the way out. With those two bulbs running on a 10 gallon tank, you pretty much have the sun right above your tank. You currently aren't adding enough CO2 and ferts to help the plants out-compete the algae.

I would shade that light, or lift it up. Window screen works well, or get some floaters. Probably both.
 

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That's right. It's a new tank, but it ran for about a month with those lights and without the CO2, with very little algae. Adding the co2 was definitely the catalyst for the algae bloom.
Unlikely, It takes a while for algae to really develop before it becomes very visible and a nusiance, probably just a timing thing more than anything else.

A tank isn't like a jigsaw puzzle where you can add pieces as you go along. You have aquasoil and high light without co2, that's a algae incubator, it just had to develop.

BTW any stirring op of the aquasoil will realize ungodly anounts of ammonia etc into the water column so if you did that it would certainly make it worse.

I would do lot of water changes, trim, cut lights back to 4 hrs, use carbon or other organic removal media and yes use co2.
 

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Discussion Starter · #12 · (Edited)
Unlikely, It takes a while for algae to really develop before it becomes very visible and a nusiance, probably just a timing thing more than anything else.

A tank isn't like a jigsaw puzzle where you can add pieces as you go along. You have aquasoil and high light without co2, that's a algae incubator, it just had to develop.
I was watching the tank pretty closely immediately before and after adding CO2, there's no doubt in my mind that before I added CO2 there was little to no algae, and a huge bloom immediately after. Maybe the CO2 accelerated the growth of algae and plants alike and just brought about an inevitable bloom sooner, but the change was really rather dramatic.

I'll try reducing the light/co2 cycle to fewer hours per day and see if that helps. I've already reduced the CO2 flow, but I can bump it back up if it would help. I was at ~2 bubbles/second, and reduced to 1. I'll look up the model of my bubble counter if people want to do a real comparison, I'd imagine the numbers don't translate between different models.
 

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I was watching the tank pretty closely immediately before and after adding CO2, there's no doubt in my mind that before I added CO2 there was little to no algae, and a huge bloom immediately after. Maybe the CO2 accelerated the growth of algae and plants alike and just brought about an inevitable bloom sooner, but the change was really rather dramatic.

I'll try reducing the light/co2 cycle to fewer hours per day and see if that helps. I've already reduced the CO2 flow, but I can bump it back up if it would help. I was at ~2 bubbles/second, and reduced to 1. I'll look up the model of my bubble counter if people want to do a real comparison, I'd imagine the numbers don't translate between different models.
I wish you luck, but you would be probably the first that reduced the co2 duration to only part of the light duration and solved their algae woes. It just doesn't work that way and I've been doing this a long time. Good, healthy growing plants will out compete algae all the time as long as there is enough of them. Tanks with high-light and no co2 become algae farms sooner or later. When something is in short supply in this case co2, the plants won't grow as well and algae has no problem in that environment.
 

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Discussion Starter · #14 · (Edited)
I wish you luck, but you would be probably the first that reduced the co2 duration to only part of the light duration and solved their algae woes. It just doesn't work that way and I've been doing this a long time. Good, healthy growing plants will out compete algae all the time as long as there is enough of them. Tanks with high-light and no co2 become algae farms sooner or later. When something is in short supply in this case co2, the plants won't grow as well and algae has no problem in that environment.
I have the lights and the CO2 on the same timer, to avoid PH drops at night when plants aren't photosynthesizing. It's easy to change though. That's why I said light/co2 cycle, it's the same thing currently.

I'm fine with bringing the CO2 back up and reducing the photo-period, but if the point is to have the plants outcompete the algae maybe the solution is to leave the lights, and the high CO2 and simply add more plants.

I'm sorry if I come across as resistant to reducing light, this is the first planted tank I've tried after many years of reef tanks. I'm used to more light always being a positive.
 

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More light is most definitely NOT a positive here. You have to have a balance of light, CO2, and nutrients.

Think of it as baking a cake. You have to have a balance of flour, sugar, eggs, chocolate, etc. If you go hog-wild and add 12 eggs to one batch of cake mix, that's gonna be one crappy cake.

Same thing here. 96w of lights over a 10 gallon tank is your problem. To put it in perspective, I have only about 80w over my 40 gallon tank. Lower your light output to one or two bulbs. Dose ferts. Keep up the CO2.
 

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Discussion Starter · #17 ·
I cranked the CO2 back up and reduced the light to one bulb. We'll see how it goes.

In the meantime, I'll see if I can find a fertilization scheme I like.
 

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Discussion Starter · #18 ·
I always hate it when people don't update threads to say what happened, so.... it worked!

I left the CO2 high, reduced light to 1 T5 bulb (which slowed, but didn't stop the algae), and then I introduced more fish and started dosing Excel. I'm going to look into other fertilization schemes, but just these minor changes have made a huge difference.

Before


After

Yeah the glass is cleaner, but look at the substrate and on the plants themselves. Drastically reduced algae.
 

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Check your bulb spectrum. If its not even close to 6500k, you will be making an algae farm no matter what you do.
I have 2 X15 watt T8's over my 10 & it is totally thriving. The water is crystal clear with NO ALGAE on plants or glass. I run 1 bubble every 2 to 3 seconds with a high end diffuser. I run 2X 6500k bulbs . Algae will out perform your plants without correct lighting spectrum , CO2, dry ferts , all need to be balanced as well as good filter flow with some surface agitation. Some surface agitation does not mean hang on the back filter. Small ripples that allow some gas exchange.
Your nitrates need to stay above 10ppms & PO4 should not crash either. PO4 should hold between (.5 - 2ppms). Added K & Fe as well as trace with boron.
If you have high nitrates out of tap you could use or cut in R/O water to reduce in comming nitrates but nitrates should stay above 10ppms at least if not 15 or more ppms.
40 to 50% water change at the end of the week for a tank reset.
Final word. Your lights are probably the wrong spectrum & too strong , your CO2 dose is off or poor diffusion. You need to stay on track with NO2, PO4 & dose EI every week. If ph dose not drop into the acid range your not getting enough CO2 into the water. Keep nutrients up drop lighting a little & check the spectrum, dose EI. my 2 cents
 

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Discussion Starter · #20 · (Edited)
Check your bulb spectrum. If its not even close to 6500k, you will be making an algae farm no matter what you do.
I have 2 X15 watt T8's over my 10 & it is totally thriving. The water is crystal clear with NO ALGAE on plants or glass. I run 1 bubble every 2 to 3 seconds with a high end diffuser. I run 2X 6500k bulbs . Algae will out perform your plants without correct lighting spectrum , CO2, dry ferts , all need to be balanced as well as good filter flow with some surface agitation. Some surface agitation does not mean hang on the back filter. Small ripples that allow some gas exchange.
Your nitrates need to stay above 10ppms & PO4 should not crash either. PO4 should hold between (.5 - 2ppms). Added K & Fe as well as trace with boron.
If you have high nitrates out of tap you could use or cut in R/O water to reduce in comming nitrates but nitrates should stay above 10ppms at least if not 15 or more ppms.
40 to 50% water change at the end of the week for a tank reset.
Final word. Your lights are probably the wrong spectrum & too strong , your CO2 dose is off or poor diffusion. You need to stay on track with NO2, PO4 & dose EI every week. If ph dose not drop into the acid range your not getting enough CO2 into the water. Keep nutrients up drop lighting a little & check the spectrum, dose EI. my 2 cents
You should actually read my post. The algae cleared up quite dramatically, and is only getting better. I was posting an update to say that I took the advice people gave and it worked.

A lot of your suggestions are great and I do appreciate them!. Increasing nutrients and dropping the light level a bit is exactly what I did.

A small quibble about the lights:
They're 24W T5s, and they're 10k bulbs. The plants seem to be going gangbusters under them. The problem was too much light and not enough nutrients (and it's been solved, I think!).

I'm new to planted tanks, and the nutrient balance and CO2 aspect of it is not something I'm familiar with. But I've run reef tanks for years, and I do know something about lighting. Running with lights other than 6500K does not mean algae blooms. Corals can (and do) photosynthesize just fine under much bluer light than 6500K, there's no reason your plants can't photosynthesize under that light too.

What's important is PAR: http://en.wikipedia.org/wiki/Photosynthetically_active_radiation The graphs on that page should give you some idea of what spectrums work best for photosynthesis.

I'm not saying there's anything wrong with 6500K lights, but it's not the only option.
 
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