BGA and lighting

Discussion in 'Algae' started by itstricky11, 25 Aug 2008.

  1. itstricky11

    itstricky11 Member

    Messages:
    42
    Location:
    Norwich, Norfolk
    Hi All,
    I have been fighting with BGA on my relatively new (three month old) high tech planted tank, and I was starting to run out of ideas until I read:

    http://www.netpets.org/fish/reference/reefref/cyanobacteria3.html

    Which suggests that lighting can be an issue. Although I have tweaked the photoperiod and the combination of lights on at the same time, I haven't examined the lighting as a whole.

    My tank is 48"x12"x12" 120L-ish, and is currently lit with 3x30W tubes:

    2x AquaGLO (http://www.hagen.com/uk/aquatic/product.cfm?CAT=1&SUBCAT=112&PROD_ID=01015850030101)
    1x SunGLO (http://www.hagen.com/uk/aquatic/product.cfm?CAT=1&SUBCAT=112&PROD_ID=01015930030101)

    Photoperiod is currently 1200-1600, siesta 1600-1800, then on again 1800-2200.

    I am injecting CO2 with a D&D kit with the powerhead swapped out for a Rhinox 5000 at about 1 bubble per second, and my JBL drop-checker never shifts from dark blue.

    7.0 pH
    0 Ammonia
    0 Nitrite
    20ppm Nitrate (Higher than I would like but tap water is 20ppm too!)
    13 GH
    14 KH

    Tank is dual-filtered, a Fluval 205 with bio media and sponges, and an eheim 2232 with purely mechanical media. Minimal surface agitation from water return.

    20% changes weekly. I was dosing Seachem ferts until 4 weeks ago, after which I haven't dosed any to try and bring the nutrient quantities down.

    Stocking is:
    2 adult Gold Barbs
    23 Cardinal Tetra (LFS couldn't count 20 :D )
    5 Cardinia Japonica (Algae Eating Shrimp)

    Is my lighting the problem? Are the two 14k tubes too much? Have I missed anything obvious? Would a UV unit help? This project has cost me hundreds already so a couple of hundred more would an annoyance but if that's what it takes...

    Any advice would be greatly appreciated. If its not the tubes I don't know what else to do other than re-home the fish and scrap the tank as I'm completely disheartened.

    TIA,
    Rich
     
  2. aaronnorth

    aaronnorth Member

    Messages:
    3,955
    Location:
    worksop, nottinghamshire
    nitrate is fine, it should be around 20ppm for plants. Low NO3 can cause BGA. Other causes are

    ammonia spkie, not always detectable on a test kit.
    direct sunlight
    dirty filter, when was it last cleaned?
    Dead spots, is the water getting pushed where the BGA is?

    removal of the BGA followed by a 50 - 80% w/c then do a 3 day blackout (no peeking or feedng) then do another 50% w/c.
     
  3. itstricky11

    itstricky11 Member

    Messages:
    42
    Location:
    Norwich, Norfolk
    Hi Aaron,
    I would have hoped that if my Ammonia has been high for 8 weeks that I would have already picked up on it :!:

    The tank never receives any direct sunlight, and filter is cleaned at the same time as water changes (dunk sponges and media carts into the syphoned tank water). BGA is trying to cover everything, even areas with high flow rates.

    I am aware of the blackout method for getting rid of BGA, however it feels to me like treating the symptoms rather than the cause - I would be much happier to do this if the BGA growth rate wasn't as fast as it currently is, as I think something else must be wrong to be causing so much BGA :(

    Thanks though!

    Rich
     
  4. aaronnorth

    aaronnorth Member

    Messages:
    3,955
    Location:
    worksop, nottinghamshire
    ammonia isnt always detectable in the water. You test kits only detect what is safe for fish. Your tank is constantly producing ammonia & it is impossible for this to be processed imediatley.

    Do you vac your substrate?
     
  5. itstricky11

    itstricky11 Member

    Messages:
    42
    Location:
    Norwich, Norfolk
    Yeah substrate is always Vacc'd, and the BGA never seems to form anywhere near as much on the substrate, it seems to be mid to higher level leaves which is what makes me believe its a lighting issue. After reading the article on tubes from lampspecs.co.uk (in the Lighting sub-board) I'm wondering about replacing my tubes with:

    2x http://www.lampspecs.co.uk/Light-Bulbs-Tubes/840-Cool-White_3/3-Foot-30-Watt-840-Cool-White-Osram
    1x http://www.lampspecs.co.uk/Light-Bu...t-Fluorescent-Tube-30W-Skywhite-Osram-30-Watt

    That'll bring my colour temps down considerably....
     
  6. aaronnorth

    aaronnorth Member

    Messages:
    3,955
    Location:
    worksop, nottinghamshire
    it wont be linked with the colour temperature, i used to have 2 x 18 000k tubes and never got BGA.
     
  7. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi itstricky11,
    You have a 30 gallon tank lit with 90 watts of T5 is it? If so that is about 3 wpg so this is fairly high lighting. You have not indicated how much of what nutrients you are dosing. Additionally, your 20 ppm nitrate reading is completely unreliable if you are measuring that with an ordinary test kit.

    I would not necessarily implement a blackout unless the BGA is out of control, but you need to look at your nitrate dosing as well as flow patterns and filter turnover first otherwise, as you say, you will be treating symptoms.

    The siesta is useless but you may need to reduce your lighting intensity by 30% at least in the short term until you resolve the issue. If you search the Algae forum for BGA you'll find an enormous amount of data regarding this issue. For your particular case we'll need to know the following:

    What is your nutrient dosing regimen?
    What is your filter turnover rating?
    Where does the BGA occur, on the plants or on the substrate?


    Cheers,
     
  8. itstricky11

    itstricky11 Member

    Messages:
    42
    Location:
    Norwich, Norfolk
    I have read *so* many articles over the last few weeks about BGA, many with conflicting advice. What I have established is that I want to avoid using (Ethromyacin?) anti bacterials, and that I'd rather not do a blackout.

    Thinking about it, my BGA problems started after I dosed the tank with Melafix to help "fix" a fish with a physical injury which became infected. (the stupid thing got stuck between a rock and the tank and rubbed its scales off). After the treatment was complete, I did two 50% changes 3 days apart, and then put carbon in the filter for 24 hours to remove the rest.

    Its 90W of T8, so its not quite as high as it looks. They do all have reflectors though, naturally.

    In answer to your questions:

    What is your nutrient dosing regimen?

    I was dosing Seachem ferts up until 4 weeks ago when I stopped dosing completely in order to try and reduce BGA levels. Dosing was as per the Seachem recommendations, and used the following pattern:
    Monday: 5ml Nitrogen
    Tuesday: 2.5ml Phosphorus
    Wednesday: 5ml Potassium and 3ml Macro Nutrients (Seachem Flourish)
    Thursday:2.5ml Nitrogen
    Friday:2.5ml Phosphorus
    Saturday:20% water change and filter clean, followed by 3ml Macro Nutrients (Flourish)
    Sunday:5ml Potassium

    What is your filter turnover rating?

    Manufacturers rating of 430lph on the Fluval 205, and 300lph on my Eheim 2232, so after media and gunk I would guess of a maximum turnover of about 500-600lph total.

    Where does the BGA occur, on the plants or on the substrate?
    On both, however it is far more prevalent on the plants than it is on the substrate. Substrate is small (2-3ml) pea gravel, over a bed of Tetra Plant under-substrate.

    I have tried dropping the lighting by 30% (One of the Aqua-GLO 18k tubes is on its own controller) and it has definitely helped.
     
  9. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi,
    I'm always very careful about drawing correlations between events in a tank because circumstantial evidence can lead us astray. I don't know enough about Melafix, or it's active ingredient Melaleuca to know what effect it would have on tank bacterial colonies. Additionally, you can perform some action on the tank and not see it's effect for weeks.

    If you check the threads I referenced you will see that stopping nutrient dosing in order to get rid of algae is generally not a good idea, especially if the algae was caused by insufficient dosing in the first place. These threads explain the science of plant growth. BGA can be associated with poor maintenance of filters such as high organic waste buildup within the filters which then breaks down to produce ammonia. BGA can also be associated with insufficient Nitrate dosing. It therefore depends on how much you are dosing relative to the amount of light. Since you report that you perform a filter clean every week then we can eliminate the maintenance issue and focus on the nitrate dosing. You may actually need to increase your nitrogen dosing.

    A 30 gallon (120L) injected planted tank normally requires 300 GPH (1200LPH) of rated filter flow in order to distribute the nutrients and CO2 properly to the leaves so your comparatively low flow rating (730LPH) could be a contributing factor. As the plants grow their increased biomass means that dosing and injection levels may need to be adjusted up. Higher biomass also results in lower flow due to blockage. Rearranging the flow pipes could help and also trimming the biomass back could help as well. You should remove infected leaves anyway so that will help reduce any blockage.

    I'm fairly certain that your difficulty lies in low nitrate or its distribution. The fact that the BGA is on the plants leaves themselves is a one indication of nitrate deficiency. Try doubling the nitrogen application.

    Cheers,
     
  10. itstricky11

    itstricky11 Member

    Messages:
    42
    Location:
    Norwich, Norfolk
    I didn't have much time to check my facts earlier, the 205 is actually rated at 680lph, not the 430 I had originally thought so the flow rate doesn't appear to be as "bad" as on my original calculations.

    I will up my dosing to the following schedule and see if it helps:

    Monday: 10ml Nitrogen
    Tuesday: 3ml Phosphorus
    Wednesday: 6ml Potassium and 4ml Macro Nutrients (Seachem Flourish)
    Thursday:7.5ml Nitrogen
    Friday:3ml Phosphorus
    Saturday:20% water change and filter clean, followed by 4ml Macro Nutrients (Flourish)
    Sunday:6ml Potassium

    Thanks for your help guys, I'll give this a shot and report back in a few days. I'm going to bump up levels of Nitrate straight away with a 10ml dose :)
     

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