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Does this tank have too much light?

Discussion in 'Lighting' started by km9172, Dec 11, 2008.

  1. km9172

    km9172 Guest

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    6:40 AM
    From the reading I've done, I'm starting to think my constant algae problem is that I have too much light.

    I have a 30g long tank (36"L x 16"H x 12"D). I have a Hagen Glo fixure (dual T5HO, 39w each bulb)

    N stays between 10-20 (according to test kit), dose 1/8 tsp KNO3 3x week
    P stays between 2-4 (according to test kit), dose 1/32 tsp KH2PO4 2x week
    K is dosed at 1/4 tsp 3x week
    CSM+B dosed at 1/16 tsp 3x week (I'm using my stargrass as my measure; and it isn't complaining about traces)
    25% weekly water changes, with an occasional 50%.

    Problem algae include:
    - BGA
    - brown hair algae

    Plants seem to be doing OK. I have:
    - Heteranthera zosterifolia (Stargrass)
    - Hygrophila difformis
    - anubias barteri
    - some type of sword
    - dwarf sagittaria

    Drop checker is light green, but recently upped it slightly to see if slightly more yellowish would help. It didn't.

    For the BGA, I've added a powerhead and hit the tank 4 times over the past 3 months with increasing doses of enrythromycen (starting from 1/2 dose, to full dose and full dose following week, then to dose + 1/2). It always comes back within a week, so I'm missing the root cause. The algae is swaying in the flow. I'm pretty sure it's doing that in defiance.

    Does this sound like a situation where less light may be called for? I'm thinking to replacing the dual-bulb fixture with a single bulb one (or asking around seeing if someone might want to trade). I can't raise the light any higher.
     
  2. Gerryd

    Gerryd Plant Guru Team
    Lifetime Member

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    Hi,

    I would remove one of your bulbs for a while and see if that helps. I would also increase your weekly water change to 50%. Not sure what test kits you are using but most of them are junk and not that accurate.

    Drop checkers are also a 'rough' estimate of c02. Just because it is yellow does not mean that you have sufficient or stable c02 levels, as they can change dramatically and in a very short period.

    It also may be that you do not have sufficient circulation to distribute your c02 and nutrients. Perhaps you need a prune?

    Also, c02 and other nutes must be increased as your plant mass increases.

    Lowering the light will help as light drives nutrient demand. Less light = less demand.

    You may also try and increase your kno3 as BGA can be induced by low kn03, high light, and low/unstable c02 levels.

    Hope this helps.
     
  3. abcemorse

    abcemorse Prolific Poster

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    BGA is typically low nitrate or organic build-up, and since your nitrates seem good maybe try 50% WC all the time. Also spot treating with excel will get rid of it till the cure is found. BBA is usually CO2, do you have a lot of surface agitation or aeration that might be outgassing a bunch of CO2? Of course lighting is a concern, I don't know how long your photoperiod is, but I found my issues cleared quite a bit by reducing period from 11 to 8 hrs. Probably have to start with one thing and give it time then try another till you isolate the cause. Good luck!
     
  4. VaughnH

    VaughnH Lifetime Charter Member
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    People have very good results using one 54 watt T5HO light on a 55 gallon tank, so I expect that a single 39 watt T5HO light would do well on a 30 gallon long tank, which is relatively shallow, further increasing the light intensity in the tank.

    When I had a 29 gallon tank, I dosed 1/4 tsp of KNO3 and 1/16 to 1/8 tsp of both KH2PO4 and CSM+B, so I suspect your dosing is too low also, given the amount of light you have. You should have rampant growth, requiring pruning twice a week for the H. difformis, and with the sword taking over the tank, if your dosing is at the right level. If you only think the plants "seem to be doing OK" that is a good sign your dosing is too lean.
     
  5. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

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    Try this, clean the filter more often, lightly vacuum any detritus etc, make sure you have plenty of plants. Do 2x a week water change for now, add Excel back after each water change. Have you calibrated the test kits you are basing the dosing on?

    Seems a bit light ....but might you might been in that range if your CO2 is poor.
    Watch fish(for too much) and plants(for enough) with the CO2. Go slow, do no make fast changes here.
    Clean the filter often.

    Also, give things 1-3 weeks time to see.
    The Excel should help if it's a CO2 issue.

    You can turn off one light without issue for now. BO and EM are the only 2 ways to kill BGA really. While low NO3 is the typical cause........Dirty filters and low CO2 seem to encourage BGA also.

    So go after all 3.
    Hit algae with everything, not just one thing.
    Tank looks better if you work on these 3 anyways.

    Regards,
    Tom Barr
     
  6. km9172

    km9172 Guest

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    6:40 AM
    I have not calibrated my test kits (and I should know better); I don't have accurate enough measuring equipment. Guess I'll buy a graduated cylinder here in the next couple of days.

    I already tried taking one bulb out of the fixture. The other light won't come on.

    My H. difformis and stargrass are only being pruned every couple of weeks. There are nutrients in the water column (I guess that's about all I can say with an uncalibrated test kit)...but the stargrass does not exhibit any signs of nutrient deficiency. I guess that probably points to a CO2 issue.

    I am dosing lean because I only do 25% water changes. I run a bucket brigade from the faucet to the tank, so I was trying to get away without 50% water changes to cut my work...that and trying to conserve water. There are also no python-compatible faucets in the house, and I am not a DIY kind of guy (tried to make CO2 reactor...I'm almost ready to try again).

    I have otos. Can I use Excel with otos? I get mixed opinions.

    I'm going to 1) increase the CO2, 2) start doing 50% water changes, 3) look at increasing dosing, 4) hit with EM after next water change 5) get a new fixture...I don't want to prune twice a week.
     
  7. km9172

    km9172 Guest

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    Here are pics (if I did it right), in case it provides any more info.
    [​IMG]

    CO2
    [​IMG]


    And to add to my earlier post, I have been vacuuming the flourite (I did a heavy vacuum a few weeks ago, but nothing improved or got worse). I have a Marineland C-220 and clean it about every 3 weeks. I'll be cleaning it more often.
     
  8. Gerryd

    Gerryd Plant Guru Team
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    Hi,

    Do you do a water change after the vacuum? If not, please do so esp after a heavy cleaning of the substrate or a replanting. NH4 will leak from the substrate and fuel algae.

    I see GSA on your Anubias and that can be low P.

    Your sword is pretty large (nice) but is a nutrient hog, you may want to trim it a bit. It also may be blocking your flow and preventing nutrient distribution.

    I use excel weekly with my WC and I have otos with no issues.

    EI is to provide non limiting levels of macro and micro nutrient, so try not to worry about test kits, unless you really want to know your levels, and have good calibrated kits.

    Also plants have differing nutrient uptake rates and demand, so using your stargrass to detect deficiencies will not automatically apply to any other plants.

    BTW what is your light duration? 8 hours should be plenty. Remember your tank is not that deep, so the light is stronger than in deeper tanks.

    Also try moving the checker around the tank to see if the color changes on placement.

    I am not familiar with your filter, but it may be undersized for your specific setup.

    Hope this helps.
     
  9. km9172

    km9172 Guest

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    6:40 AM
    I always do WC after I mess with the substrate. My flow is such that everything (including BGA) is swaying moderately in the flow (except for the area around the anubias...haven't got that worked out quite yet).

    I've been moving my drop checker around, and CO2 seems to be the same everywhere I check it.

    I was doing less water changes to try and conserve water (and because it was a pain). I suppose I can consider that expiriment a failure. I think I'll be going strict EI for a few weeks to see if I can establish a better baseline. I also think I may need to increase my CO2 levels slowly.

    The Marineland C220 is rated for 250GPH. However, even when I replaced the tubing, cleaned out the intake/outake with a brush, and removed all media & baskets from the canister, cleaned the impeller, it seems to have slowed to consideribly less that was it was when I first got it. Haven't figured that one out yet.
     
  10. km9172

    km9172 Guest

    Local Time:
    6:40 AM
    Fixed

    After changing out the light to a single T5 (pre-Christmas sale at Exotic Aquarium netted me single light Hagen GLO 36" fixture for $60), changing the CO2 diffuser for a Plant Guild reactor, and doing 50% twice weekly WCs at EI recommended starting dosages, the algae has all melted away.

    I don't know which change it was that "fixed" it, but I have a good starting base now. Thanks all.
     
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