# Need some help with CO2 and Brown Algae (Diatoms)



## lassi001 (Jul 6, 2017)

Specifics of the Tank:

300 Gallon Freshwater Aquarium, 30" tall
CO2 with a pinpoint PH controller.
2 Wavemakers (Vortech MP40's)
Sump with Pinky Filters and Bio Balls
2 Largemouth Bass and 1 Bluegill (Sunfish). Each are about a pound. (Yes, a lot of waste coming from these guys!)
Eco Complete substrate with root tabs throughout.
3 Kessil 90W Tuna Sun running about 7 hours on a timer. They ramp up from 5%, 25%, 50%, then back down 25%, 5% and 0% to turn off. The light color ramps up and down as well as intensity over about a 1-2 hour period for each setting.

Setup since May 7, 2017. We had cycled media from another tank as well as added Dr. Tim's one and only nitrifying bacteria to the sump. Water parameters as of yesterday are:
Ammonia: .25 ppm
Nitrite: 0
Nitrate: 40 ppm

I know the Nitrates are higher than they should be and I'm doing water changes to lower it. And I know I want the Ammonia at 0 so the water changes will get me there.

Around 2 weeks after the install we added some plants. Crypts, Swords, and Dwarf Hair Grass are the main one's I'm concerned with.

In the beginning we planted the DHG and gave it good trims as it was growing to stimulate horizontal growth. It was doing well. Then we started with the CO2 and it started to brown. Then all of the Crypts and Swords have the brown algae (diatoms) on it because I can wipe it off. A good bit of the tank has the brown algae. We also have a small area of the white worms on the glass where some sunlight hits the tank. 
Before starting CO2 KH was 8-9 and GH was 5.
After starting CO2 KH is 2 and GH is 4.

PH without CO2 is currently at 6.10. The only way we can get the CO2 to turn on is if we lower the PH below 6. I believe we need the PH to be closer to 7 for these plants and our fish.

Here are my questions.

We want to run CO2 to have healthier plants, but the PH is so low. How do we raise the PH so we can add CO2? Will this be a constant battle of manipulating the PH so we can add CO2?

Will water changes really get rid of the brown algae (diatoms) or are we missing something in the water parameters that is causing it?

Does the lighting cycle we have set seem good? Obviously we don't want to promote green algaes and haven't had any issues with that so far.

Fish have always been healthy. Their input and output has never changed.


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## Michael (Jul 20, 2010)

Welcome to APC!

I don't use CO2 in my tanks, so others may have better advice. But it is very difficult to permanently change pH, and it is better to work with the water chemistry you have.

I'm going out on a limb with this advice, but here goes. For now, turn off the CO2. Put the lights on a siesta schedule to manage natural CO2. Add some fast growing floating plants, like frogbit, duckweed, or hornwort to absorb ammonia and nitrates. You can take them out when the tank stabilizes.

Dwarf hair grass is a challenging species, and may never do well in this tank. You might try dwarf sagittaria instead--with the size of the tank and the fish, it should look fine and be easier to grow.

I will be interested to see what others say. Please show us some photos, I love native fish.


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## hoppycalif (Apr 7, 2005)

That is a very bright light! Before you can make good decisions on CO2, fertilizing, etc. you need to have a good idea about how bright the light is. You need a PAR meter to measure that. If you have as much light as I suspect you do, you need to be running the CO2 about as high as the fish can live with, or it won't be at all easy to avoid major algae problems. It is possible to borrow/rent a PAR meter for a few days so you can obtain the information you need.


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## lassi001 (Jul 6, 2017)

Michael: we tried to add frogbit but couldn't keep it from going into the overflow. How does someone accomplish this when you're getting them started? I even put some in my 55 gallon and they just kept getting blown around in the return water. We will try turning out the lights for a few days. Any idea how long to give it?


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## lassi001 (Jul 6, 2017)

hoppycalif said:


> That is a very bright light! Before you can make good decisions on CO2, fertilizing, etc. you need to have a good idea about how bright the light is. You need a PAR meter to measure that. If you have as much light as I suspect you do, you need to be running the CO2 about as high as the fish can live with, or it won't be at all easy to avoid major algae problems. It is possible to borrow/rent a PAR meter for a few days so you can obtain the information you need.


Do you say it's too high lighting because it's a freshwater planted tank? Who could ever use these things on 100% then? I've always wondered. What is the ideal light output we're looking for on the meter? Do they make them submersible or can we just test the light near the substrate on the outside of the tank?


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## hoppycalif (Apr 7, 2005)

Those lights are made to work well on a reef tank, which needs a lot more light than a freshwater planted tank. That almost guarantees that they produce too much light for a planted aquarium. And, the photos, I found online, of tanks with that light look like they are much too bright. 

PAR meters made for use in water have a waterproof sensor. You put the sensor in the tank and the readout module is kept outside the tank, dry. The way to measure the light intensity in the tank is to put the sensor on the substrate, in the middle of the tank, and read the meter. The reading should be about 25-35 for low light, 40-55 for medium light, and up to about 100 for high light. (These values are not accepted by a lot of people, but they are what I use, based on experience and advice from others over several years.) If the light gives you too much intensity you can raise the light farther from the substrate or, if it is dimmable, just dim it.

You can also measure the intensity of the light in air at various distances, and use those numbers to figure out how far it should be from your substrate to get the intensity you want. The water in the tank doesn't have much effect on the intensity. This lets you buy a cheap digital lux meter (Ebay and other online stores) and measure the lux vs distance. Divide the lux by 70 for a crude estimate of what PAR you have.


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## Michael (Jul 20, 2010)

I am not as familiar with Kessil as Hoppy, but the few I've seen were extremely bright! In case you didn't notice, you can rent a PAR meter from Hoppy. Fortunately, my local club has a PAR meter available to members, and it has been invaluable. After measuring many tanks, I agree with Hoppy's categroies of low, medium, and high light.


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## Khaoticworld (Apr 14, 2017)

I don't run CO2 but from my experience brown algae almost always happens in a newer setup tank. Also I haven't had too much issues growing some swords crypts and dhg at 6 ph in varying ranges of light. They do better growth now that I've started experimenting on ways to bring up my ph to about 6.8 and able to keep it steady.

But again that's without CO2.

Sent from my LGMP260 using Tapatalk


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## hoppycalif (Apr 7, 2005)

I assume that tank was filled with tap water. What is the pH of the water from the tap, and what is it after the water sits for a day? It is unusual to have a pH as low as 6 with tap water, since that water would tend to erode copper piping. Have you calibrated your pH probe?


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## Mystery Roach (Jul 10, 2017)

Hello lassi001, I am in agreement here that the water from your tap should have a higher pH than it does. You should be able to calibrate your pH meter with a bottle of Standard Reference Solution (pH 7.0). I use General Hydroponics 8oz. I would recommend in addition to your pH meter getting test kits for both gH and KH so you can test your water.
As for your question about how to raise pH, Seachem sells "Alkaline Buffer" which will raise both your pH & KH. I use alkaline buffer and shoot for a neutral 7.0 pH which from what I have read is a good environment for most aquarium plants and tropical fish. Not that there aren't exceptions to that rule, so do your research. Note, do not use Acid Buffer as Seachem recommends or you will see pH swings!

If indeed your water is that pure coming out of the tap, you will likely need to address your General Hardness (GH) as well. General hardness affects the osmotic regulation of fish, which is their ability to maintain fluid balance and electrolytes. Seachem sells a product called Replenish which raises general hardness. (Those two products are inexpensive).
I use both of those products as measured additives to my water because I use RO water for my aquariums. I mix .6 ml (1/8 tsp) of alkaline buffer, and 6 ml of Replenish to 4 gallons of RO water. That raises my KH up to around 57.3ppm (3dKH), and my GH up to 107.4ppm.

Adding CO2 will lower your pH, so what I am doing would only be for your reference.
It's important to know that I do weekly 50% water changes as a rule. The lower your pH is the easier it is to have it crash very low. I have been doing this for a while now but when I started I monitored my pH very closely so I could learn about the interactions that will affect pH such as bio-load V.S. water changes. If I was going to use CO2 I would likely go with a higher pH than what I run now.

If you wish to experiment with fish in your tanks, you should try your best to make gradual changes for the benefit of your fish. I never killed any during my journey but I certainly pissed them off on several occasions!

Hope this helps.
~Roach


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