Pearling

Discussion in 'General Planted Tank Discussions' started by Terry, 21 Feb 2008.

  1. Terry

    Terry Member

    Messages:
    47
    Location:
    Cowplain, Portsmouth
    My plants all look reasonably healthy and no algae however, there is no evidence of ‘pearling’ on any of the plants. :?

    Pressurised CO2 is controlled via solenoid and timer and is on an hour before the lighting and off as the lights go out. The 4dKH drop checker (JBL) is showing green as per the instructions. Lighting used to be on for 10 hrs a day but recently have increased to 12 hrs but this has made no difference. Grateful for any thoughts please?

    Details:
    L121x H50 x W38 (48” x 20” x 15”) 250 ltr
    2 x 42 inch Lamps T8 40 watts (1 x Power-Glo and 1 x Aqua-Glo) both with reflectors. Lamps are only a few weeks old.
    External Filter: EHEIM 2026 Prof II
    Temperature 26 - 27
    Substrate: Flora Base with Sand on top
    Dose Easy Carbo 5ml daily, trace elements every other day and liquid feed Profito once a week after w/c.
    Carry out 25% water change weekly; Use mix of RO + Tap Water
    KH = 7
    PH = 7

    Plants
    Echinodorus Ozelot Green (two of which are currently in flower)
    Anubias Nana (new leaves weekly)
    Microsorium pteropus
    Aponogeton Ulvaceus recently planted and already at the surface.
    Cryptocornye Becketii
    Hygrophillia Difformais
    African Tiger Lotus
    Nymphaea Lotus
     
  2. Dan Crawford

    Dan Crawford Founder Staff Member

    Messages:
    3,266
    Location:
    Daventry, Northants
    hiya, somone else asked this a week or so ago and the general consensus was not to worry. As you have already stated your plants are healthy so try not to worry about it. Have a quick search for the previous query and see what that says.
    cheers
    dan
    P.s if anything I would expect the fern to pearl the most
     
  3. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi,
    Pearling is caused by a combination of many factors, including the rate of photosynthesis. With T8 lighting and low nutrient concentration you normally don't have the intensity to drive the photosynthesis rate very high. Pearling is seen more often in high wattage tanks teeming with high nutrient levels and high CO2 concentrations.

    As Dan says pearling, although a fascinating and novel phenomenon, is really not necessarily an indication of great tank health. There are plenty of algae infested tanks out there that pearl so I'd probably consider my tank (and my technique) a success if I get nice growth, pretty colors and minimal algae. :D

    Cheers,
     
  4. Themuleous

    Themuleous Member

    Messages:
    4,126
    Location:
    Aston, Oxfordshire
    I think the issue here is that you've only got 1.5wpg, so the plants are unlikely to pearl unless you upped the lighting. However as Dan says, pearling isn't the be all and end all. Yes its nice to see but if your plants are healthy then what does it matter.

    Sam
     
  5. George Farmer

    George Farmer Founder Staff Member

    Messages:
    7,091
    Location:
    Cambridgeshire
    Are you dosing NPK? That would improve growth.
     
  6. TDI-line

    TDI-line Member

    Messages:
    1,535
    Location:
    Yaxley, Peterborough
    I chnaged from T8's to T5's, a few days later everything is pearling.
     
  7. Terry

    Terry Member

    Messages:
    47
    Location:
    Cowplain, Portsmouth
    Thanks to all for your comments.

    Dan - found the query you are referring too, not sure how I missed it the first time around. :oops:

    George - Yes, I've only just started with NPK and it has been noticable on the plant growth. I will increase my water change up to 50%.

    Thanks again.
     
  8. .jaap.

    .jaap. Newly Registered

    Messages:
    15
    Location:
    Netherlands
    Some plants species pearl easily while others usually don't. None of the plants on your list are especially good at pearling. In fact, I think pearling of Anubias, Crypts, Echino's is not a healthy sign.

    If you want pearls you should have sufficient light and nutrients (incl. CO2) but also the plants species that can make good use of that.

    bubbels-2.jpg
    bubbels-5.jpg
     
  9. Ed Seeley

    Ed Seeley Member

    Messages:
    3,262
    Location:
    Nottingham
    Why? Mine pearl along with other plants in my tank and they are thriving. My E.'Oriental's are growing like never before and the Anubias 'Petite' are racing away (for Anubias...)
     
  10. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi jaap,
    I guess I'm not sure why pearling Echinodorus & Crypts would be an unhealthy sign. Mine pearl as often as my stems and are among the healthier plants in my tank. :wideyed:

    [​IMG]

    [​IMG]

    Cheers,
     
  11. .jaap.

    .jaap. Newly Registered

    Messages:
    15
    Location:
    Netherlands
    The bubbles that you see are probably strings of air bubbles that originate at specific spots on the plants leaves and not in between.

    It seems to me that at these points the leave is damaged, enough to let the air out on that spot.

    This is different from the bubbles that you see on the pictures above, where oxygen is produced over the entire surface of the leaves, and collects into bubbles that stick a while before they are released.

    I am sure that if you tune down the light a bit just so that the strings of bubbles no longer appear, growth rates will still be very acceptable.

    On the other hand, I have never managed to completely avoid these strings of bubbles the entire day. A few of these strings at the end of the afternoon are probably a good sign that the plants are happy with what you do to them. But I would not want to overdo it, I think a damaged spot on a leaf is a good foothold for algae.
     
  12. Ed Seeley

    Ed Seeley Member

    Messages:
    3,262
    Location:
    Nottingham
    Sorry I don't understand the logic here.
    Surely the fact that you can more easily see where a leaf is damaged because there are bubbles coming from it doesn't mean the leaf isn't damaged if there are no bubbles!

    Turning down the lights will cause less growth too so why do that to stop the bubbles unless you don't like their effect?

    And anyway I don't consider this pearling per se as it will occur after trimming, even before non-trimmed plants are pearling.
     
  13. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi,
    The evidence I have doesn't support this theory. There is no reason why oxygen would be produced in stem plants and yet only air bubbles form on these specific plants at the same time of day each day.


    Well, if you check the photos I posted you'll see that the distribution of bubbles is uniform over the leaf. That would mean severe damage to the leaf, which as you can see is clearly not the case.

    I don't see any difference between the bubble production on the photos you show versus the photos I show. The manner and behavior of the bubbles is identical. Additionally, I have not seen any data which indicates that plants produce air. Of all the gases the plant could produce "air" seems unlikely since it is composed of over 78% Nitrogen, a valuable commodity within the plant.

    The data I have indicates that the string of bubbles are composed of the same material the lager bubbles are made of, namely Oxygen. In the case where the bubbles stick this could be explained by higher surface tension, whereas the stream of Oxygen bubbles escape due to lower surface tension.

    In my opinion, as long as you have pearling you will never prevent the streaming bubbles because they are oxygen, being produced by photosynthesis in exactly the same wasy as that of your Riccia. A good test would be to capture the streaming bubbles with a test tube or vial. When you collect a sufficient volume of these streaming bubble pull out the vial and light a match to the mouth. If it flares that means it was oxygen.

    Additionally, it has been my experience that damaged leaves would only attract algae if the leaf itself were unhealthy. I routinely damage quite a few leaves during trimming and they do not develop algae.

    Here is an example of an Echinodorus leaf that has sustained damage. As you can see this leaf routinely pearls and has never had algae. Right next to this leaf on the right is a stem leaf pearling. This Echinodorus leaf grew to just under 50cm.
    [​IMG]



    Cheers,
     

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