# BBA and CO2



## Marauder (Apr 17, 2006)

I am getting BBA on various plants in my 75g tank (usually C. Moehlmannii and Wendelov). It has pressurized c02, a 4x54watt T5HO Tek light, and I fertilize using the EI method.

If I place these same plants in a low light 10 gallon, the BBA goes away. I assume this from steady, non-fluctuating C02 levels.

I've tried running c02 24/7, on 12/off 12, and everything in between. The BBA always returns.

Without going to a controller, how can I maintain steady c02 levels in my 75?


----------



## carpguy (Feb 3, 2006)

Marauder said:


> If I place these same plants in a low light 10 gallon, the BBA goes away. I assume this from steady, non-fluctuating C02 levels.


I think its much more likely the change from high to low light that's doing in the algae.

I'm not so familiar with T5s and just what not quite 3wpg means for them (compared to CFs f'rinstance) but you've got a pretty good bit of light in there&#8230;

What sort of photoperiod are you using? Have you tried scaling that back a bit?


----------



## kunerd (Aug 2, 2007)

have you tried dosing excel


----------



## hoppycalif (Apr 7, 2005)

One way to maintain steadier CO2 levels is to go with a lower CO2 level, but leave it on for 24 hours a day. The best reason for shutting off the CO2 at night is to give the fish a break from the high level, and allow oxygen to build up at night. But, if you just run a lower, but steady CO2 level that shouldn't be a problem for the fish, running even at night. I am going to try this at about 15 ppm of CO2 when I set up my tank again today. I will use a mixed soil/soilmaster substrate, reduced fertilizer level, 1.6 watts per gallon. My goal is far less algae, slower but healthy growth and trying something new for me. I don't use a controller for the CO2, just adjust the bubble rate and watch the CO2 level to be sure that it is an appropriate rate.


----------



## Marauder (Apr 17, 2006)

carpguy said:


> I think its much more likely the change from high to low light that's doing in the algae.
> 
> I'm not so familiar with T5s and just what not quite 3wpg means for them (compared to CFs f'rinstance) but you've got a pretty good bit of light in there&#8230;
> 
> What sort of photoperiod are you using? Have you tried scaling that back a bit?


The Moehlmannii are growing like crazy under two All Glass screw-in CF bulbs in the 10 gallon tank and without any BBA. They always got covered in BBA in the 75g and wouldn't grow.

The Tek light has turned into a noobie again. It's an absolutely insane amount of light. With that being said, I still had this BBA issue with my old 2.7wpg combination of compact flourescents and NOF bulbs. Therefore I believe that fluctuating C02 levels are to blame.

My lighting is still 12on/12 off.

I've used Excel. It helps but isn't the long term solution that I'm looking for.

I'll try running lower C02 levels 24/7 and see if that helps. Although I have a gut feeling that I should have lots of C02 to compliment the lights.


----------



## livingword26 (Nov 4, 2007)

I have had a similar problem in my 36 bow. I have tried everything that there is to try. I was running my 96 watts of T-5 lighting for 12 hours, and my CO2 on for 24-7 I had a constant ph drop of about 1.2, which puts me over 30ppm, and I was dosing Excel. There was very little fluctuation in co2 levels in the morning. I have come to the conclusion that it is the light, and I have recently cut my light in half, down to 48 watts, and shut off my co2, using excel only. If this doesn't kill it I will lower it some more. Anyway, good luck with yours.


----------



## hoppycalif (Apr 7, 2005)

The "pH drop of 1" method does not work reliably for measuring the amount of CO2 in the water. The only method that is cheap and reasonably accurate is the drop checker method.

A pH drop of 1.0 only means the amount of CO2 in the water is 10 times as much when the pH is low as when it is high. A drop of 1.2 means it is 16 times higher when low than when high. But we have no way to know how much is in the water when the water is "degassed". So, that amount could be as low as .5 ppm, which would give you only 8 ppm in the tank, not 30 ppm.

Use a drop checker and you won't have a problem knowing how much CO2 you have.


----------



## Carissa1 (Aug 25, 2007)

Why would the test degas to .5ppm? Are atmospheric conditions such in some places that it would come to equlibrium that low?


----------



## houseofcards (Feb 16, 2005)

Marauder said:


> The Moehlmannii are growing like crazy under two All Glass screw-in CF bulbs in the 10 gallon tank and without any BBA. They always got covered in BBA in the 75g and wouldn't grow.
> 
> The Tek light has turned into a noobie again. It's an absolutely insane amount of light. With that being said, I still had this BBA issue with my old 2.7wpg combination of compact flourescents and NOF bulbs. Therefore I believe that fluctuating C02 levels are to blame.
> 
> ...


If you runing strong light for 12hrs that gives you very little wiggle room in terms of algae control. Instead of cutting back on intensity cut back on duration. 12 hours is to long especially if your running at full strength (both lights). I don't know how old the tank is but with strong light it's always best to start off in the 6 to 7 hour range and work up to maybe 8 1/2, 9 max. Everthing is relative. How often do you change your water? How often do you clean the filter? How much do you feed and how many fish are in the tank? All these tanks will determine how much wiggle room you have. If you shorten the light duration and keep the water clean you will cut back on algae.


----------



## hoppycalif (Apr 7, 2005)

Carissa1 said:


> Why would the test degas to .5ppm? Are atmospheric conditions such in some places that it would come to equlibrium that low?


I don't know how low the equilibrium CO2 concentration will be, or even it is will be the same from day to day. Remember, there is less than one percent CO2 in the atmosphere out in the open air, but inside a house there are sources of CO2 to raise the level. When I, and others, have checked how low the concentration gets, vs time, we found it never seems to stop dropping. It takes more than a couple of days to be able to expect it to reach equilibrium. And, it makes a big difference whether the final amount is 3 ppm or .8 ppm. I was also not successful in finding a standard method for accelerating the drop to get reproducible results. There are undoubtably several ways that would work, but if they involve any complexity, such as running an air line to the sample, the test is no longer simple and easy.


----------



## Marauder (Apr 17, 2006)

houseofcards said:


> If you runing strong light for 12hrs that gives you very little wiggle room in terms of algae control. Instead of cutting back on intensity cut back on duration. 12 hours is to long especially if your running at full strength (both lights). I don't know how old the tank is but with strong light it's always best to start off in the 6 to 7 hour range and work up to maybe 8 1/2, 9 max. Everthing is relative. How often do you change your water? How often do you clean the filter? How much do you feed and how many fish are in the tank? All these tanks will determine how much wiggle room you have. If you shorten the light duration and keep the water clean you will cut back on algae.


I cut my photo period back to 9 hours. That helped a lot. Since it's a Tek Light 4x54 it only has one power cord (two switches though). My tank is four years old and very well seasoned. I use a Magnum 350 and I change out the filter floss every few weeks. The Magnum also doubles as a C02 diffusor/reactor.

The bio-load is light with just three 8" Hujetas and three Botia Modesta (aka redtail loach). They are fed frozen krill and blood worms.

I've been using "EI" and I do 50% water changes weekly. Plant growth and health has been OK. Still have some BBA on my crypts and GSA on my Anubias. I feel that doing 50% water changes every week is akin to pulling my hands off the wheel of a race car at full throttle. I've since cut back to 50% changes bi-weekly and plant health improved and algea declined.

I plan on getting a drop checker and switching to PPS.

I feel that stability is extremely important with this light level.


----------



## livingword26 (Nov 4, 2007)

hoppycalif said:


> The "pH drop of 1" method does not work reliably for measuring the amount of CO2 in the water. The only method that is cheap and reasonably accurate is the drop checker method.
> 
> A pH drop of 1.0 only means the amount of CO2 in the water is 10 times as much when the pH is low as when it is high. A drop of 1.2 means it is 16 times higher when low than when high. But we have no way to know how much is in the water when the water is "degassed". So, that amount could be as low as .5 ppm, which would give you only 8 ppm in the tank, not 30 ppm.
> 
> Use a drop checker and you won't have a problem knowing how much CO2 you have.


I've read this several times trying to make sense out of it. If I understand what you are saying, then if I am able to completely degas my sample down to 0, then a 1.2 drop in ph in my tank, from my co2 injection, means that I have 0 ppm co2. Am I missing something?


----------



## hoppycalif (Apr 7, 2005)

livingword26 said:


> I've read this several times trying to make sense out of it. If I understand what you are saying, then if I am able to completely degas my sample down to 0, then a 1.2 drop in ph in my tank, from my co2 injection, means that I have 0 ppm co2. Am I missing something?


Unless you degas the water sample in an environment with no CO2 in the atmosphere you can't get it to zero ppm of CO2. CO2 dissolves very easily into water and comes out of solution equally easily. So, a sample of water in an environment with any CO2 at all in the atmosphere will always contain some CO2. The problem is determining how much CO2 that is, and determining how to make sure that every time you do this test you end up with that same amount of CO2 in the water.

You can start with distilled water. Add enough bicarbonate of soda to give it a 0.5 dKH hardness. (Better yet, dilute known 4 dKH distilled water, used for a drop checker, with distilled water to get 0.5 dKH - 1 part 4 dKH water with 7 parts distilled water.) Use a straw to blow your breath thru a sample of that water, dissolving some CO2 in it. Then, using a calibrated pH probe, measure the pH of that sample of water every few hours (or after whatever standard method you want to use for degassing), and see how long it takes to reach equilibrium with the air, and at what pH it does that. Use that pH and the 0.5 dKH to determine the ppm of CO2. Repeat this several times with different conditions in the room where you do this - windows open, closed, no one else in the room, several people in the room, a gas oven having recently been used, or not used, gas furnace running for heat or not, fireplace in use or not, etc. See what the equilibrium amount of CO2 is for each test. If they are all about the same, you have the basis for using this method to measure the CO2 in the tank water. That would be some work, but the results would be very interesting and useful. Please report your results here if you do this.


----------



## Rob Tetrazona (Jun 21, 2005)

I have 2 75's with an almost identical setup to Marauder's except I only have 108W of T5HO on my TekLights (2 bulbs) & a Milwaukee CO2 controller. I get BBA on my slower growing plants, filter parts, and SoilMaster. I am running 10 hours of light though. Sounds like I need to cut back on the light.

I also have a non-planted 75 with a 20W shop light (1 bulb) running for 6 hours that gets BBA on the rocks. I'm confused why the BBA in this tank is doing so well.


----------



## DVS (Nov 20, 2005)

hoppycalif said:


> and allow oxygen to build up at night.


Not to hi-jack this thread, but I don't understand the logic here. Levels of CO2 and oxygen are independent of each other, therefore stopping CO2 will do nothing to allow build up of oxygen. In order for oxygen levels to "build up" its going to have to be added from an outside source probably increased surface turbulence(?), but you don't mention increased aeration. Plants and animals are all still respiring at night meaning that oxygen levels continue to drop regardless of CO2 supplementation. Even in the case of increased aeration at lights out, alot of tanks have higher then equilibrium oxygen content (any tank that pearls). In this case, aeration will actually cause the oxygen level to fall more rapidly.

Curious as always,

Dave


----------



## hoppycalif (Apr 7, 2005)

I didn't go back to the full quote of what I said, but I should have said I have the filter spray bar at the top of the tank pointed so I get some surface movement - slight ripple. That way I get better transfer of atmospheric oxygen into the water. I shut off the CO2 at night to give the fish a break, and the surface ripple allows oxygen to transfer to the water, which also helps the fish.

Pearling doesn't mean the water is saturated with oxygen. It means the plant is producing oxygen faster than it can dissolve into the water. Oxygen doesn't dissolve into water as readily as CO2 does, so pearling is possible. Aeration adds oxygen to the water primarily, if not entirely by adding surface turbulence. And, it is highly unlikely that it will reduce the amount of dissolved oxygen in the water.


----------



## DVS (Nov 20, 2005)

Just trying to understand what your saying, I use different methods and obviously are tanks are different.

While pearling does not necessarily mean oxygen is a saturation level, by deduction I suspect in my tank it means that the tank oxygen level is higher then the atmospheric equilibrium. I would suspect this because pearling usually occurs sometime into the photoperiod, (in my case the last half) and while photosynthesis may take awhile to go to full production, I would think it would be less then 4 hours. On the other hand as tank oxygen levels increase the rate of oxygen absorption will slow (and pearling will result). If oxygen levels are above equilibrium then any additional aeration of tank water will decrease the amount of time it takes for the tank to return to equilibrium levels (or increase oxygen dispersion). I have used a dissolved oxygen meter on the water before lights on and found dissolved oxygen at what would be equilibrium levels, which based on plant and animal respiration at night would suggest starting at above the equilibrium level. I can see how reducing CO2 input may increase the ratio of oxygen to CO2 which should benefit the fish. As far as oxygen levels by themselves, if the plants are growing, I can't see why oxygen levels would increase. Unless the tank was below equilibrium while plants are photosynthesizing, in a planted tank with fish (vs. a fish tank with plants), I don't think this should occur. Now I have to borrow the oxygen meter from work again .


----------



## Jeff.:P:. (Nov 20, 2007)

Excell double dosage for a couple weeks took care of my BBA.


----------



## natureman187 (Aug 15, 2007)

Jeff.:P:. said:


> Excell double dosage for a couple weeks took care of my BBA.


You're a lucky one then.


----------



## Jeff.:P:. (Nov 20, 2007)

> You're a lucky one then.


Thanks  . I really watched how much food was going in and my nutrient levels. At that point I had DIY C02; which I made sure was running full time, and smoothly, not sure of the C02ppm. Double dosed excel every day or other day, sure enough it turned red and then SAE's & shrimp finished it off. I think the regiment/dosage of Excel over time kills it easily. And increase C02.


----------

