uneaven lighting causing issues

Discussion in 'Lighting' started by Matt Holbrook-Bull, 25 Oct 2007.

  1. Matt Holbrook-Bull

    Matt Holbrook-Bull Founder

    10 Jun 2007
    Dorset, UK
    had an epiphany moment this morning while in the shower ... like you do.

    all my T5 lighting is compact, therefore only 21" long (i was offered a cheap unit)... so, my effective 110watts, is squashed into only about 2/3rds of the tank.. that makes my wpg about 4 over that area :wideyed: no wonder im fighting algae issues.. this also explains why my hygrophilla's are so nutrient thirsty at the moment, and show signs of faltering after only 2 days of a deficiency (i ran out of NO3).. theyre being driven at about 200% the rate i want them to be.

    think it might be time for an early christmas present and get a full length luminaire.

    this also proves that all EI scheduling calculations are very much dependent on the amount of light you have... so if your running more light than the average (we wont know what figure Tom Barr tested EI on) then you need to increase your dosing accordingly. this is obvious I know, but worth pointing out.
  2. beeky

    beeky Member

    21 Aug 2007
    Chippenham, Wiltshire
    It's a good point.

    My tank is 3' and when I used T8 tubes they were something like 30" as there was a few inches all the way round that was darker than the middle, and the edges were where I was planting my higher light stem plants. My new T5's now fill the edges completely, so I'm happy.
  3. nry

    nry Member

    23 Oct 2007
    Cumbria, UK
    Ditto exactly - I switched from a single 36w PC T5 tube over to 2x15w T8. Less intense, less wattage, but a much better spread over the tank surface area (24"x12"). All plant growth is improved, glosso and p.helferi most noticeably, and the algae issues on the plants directly below the old PC T5 are gone 100%.

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