Lighting and flow for 90cm 200L+ tank

Discussion in 'Lighting' started by Ray, 7 Mar 2008.

  1. Ray

    Ray Member

    Messages:
    474
    Location:
    Switzerland
    Folks, could you sanity check this for me please:

    I plan to do a low light low maintenance C02 Asian theme tank. Plants will be mosses, ferns, various crypts, Blyxa, C. Helfrei and Danoi.
    Tank is 90cm * 45cm * either 50, 55 or 60cm high - I've yet to decide. So we are looking at either 200 or 240 litres (or, disturbingly, 180L or 220L once you take into account the thickness of the glass :wideyed: ). It will be a rimless, braceless "pool" aquarium and it will be drilled with bulkheads for filter in and out. Heater will be a Hydror exteranal heater, CO2 will be via an Aquamas external reactor. So there will be no visible tubes into the tank at all.

    Question 1:

    Will 2*39W tubes = 78W T5 HO with reflectors be enough? The first gives around 1.25 - 1.5WPG but this is T5 so I _think_ according to Colley's multiplier (http://www.ukaps.org/forum/viewtopic.php?t=537&start=16) this should be ok. Anyone with experience?

    Question 2:

    According to the 10*golden rule I need around 2000/LpH flow. Can I get away with a single Tetratec EX 1200? If not can you connect multiple filters in parallel to one inflow/outflow and combine the flow rates or do I need to invest in a big expensive Eheim 3e?

    Obviously answers to both questions effect the budget significantly...
     
  2. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    I've never really been that convinced that the light output from a T5 is that much greater than a T8. Yes they are more intense, ie look brighter, because the surface area providing the light is a lot smaller.

    Back to your question though. Yes I would think 1.5wpg is probably OK but others may have more knowledge than me with low light tanks.

    I would think a Tetratec 1200 would be fine. Water movement isn't quite so critical in a low light tank.

    James
     
  3. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    My last comment about T5's and T8's got me interested so I went off to see if I could find any tests that had been done.

    Found some interesting results. Seems as though it depends on how long the tube is to how more efficient the T5 is over the T8. The shorter the tube the more efficient the T5 appears to be. It's hard to get exact comparisons as T5's and T8's seem to have different wastage's. As a rough guide T5 tubes around the 18 Watt figure are about 35% more efficient than equivalent T8 tubes. But at around the 54 Watt mark this figure comes down to about 15% more efficient.

    Sort of explains why I never really noticed that much difference as I use long tubes on my 120cm tank.

    James
     
  4. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,952
    Location:
    Chicago, USA
    Hi James,
    Good stuff. Does the data indicate the contribution of reflectors? I use CF which I'm totally convinced has much more efficiency so perhaps that's the difference. I also see that there appeared a lot more complaints of algae since the advent of T5 so that convinces me as well. :wideyed:

    Cheers,
     
  5. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    No idea about the reflectors. Probably not as reflectors can give odd results depending on the parabolica of the reflector.

    The evidence I've seen suggests that watt for watt linear T5's are better than PC T5's.

    It's easier to cram more wattage of PC T5's in under a hood than T8's which may also explain the higher light levels and more algae. Also due to the smaller diameter of T5's they have better penetrative power through the water.

    James

    EDIT: It seems the reason that linear T5's are better than PC's is because of the reflector. PC reflectors tend to reflect more light back onto themselves rather than into the tank compared with linear T5's.

    Also of importance is the type of ballast that is used. T8's tend to use the more common magnetic ballast which is not as efficient as an electonic one which are the norm with T5's. I used to use electronic ballasts with my T8's which creates more light output.
     
  6. Ray

    Ray Member

    Messages:
    474
    Location:
    Switzerland
    Thanks James, that's very interesting. Would you be prepared to link to the study you found?

    So we have some effiencecy improvement due to reduced restrike from the T5, some from digital ballast and some inherant efficiency gain from T5 - looks like it should take me over 2WPG in any case.

    Do I put heater and CO2 in the filter intake or the return tube?

    Also James, would you rate the mid size CO2 reactor from Aquamas that you have as a good trade off between flow reduction and CO2 dissolution?

    Thank you,

    Ray
     
  7. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    Hi Ray,

    Didn't actually find a study so to speak. Just searched the web for Lumen figures for the same type of T5 and T8 tubes and then worked out the Lumen per watt figure for each. May not be the most accurate but gives you a rough idea I think.

    I always recommend putting heaters and CO2 reactors on return line as then you have cleaner water passing through them.

    Water flow is reduced with the CO2 reactor attached but for me it is well worth it as it is almost maintanence free, out of sight and works really well.

    James
     
  8. SuperColey1

    SuperColey1 Member

    Messages:
    2,685
    Location:
    Lincoln UK
    1.5WPG + T5 + Blyxia = answer to the 'more light' question (in my eyes anyway)

    n.b. only 0.9WPG is T5 (10 hours) and the other 0.6WPG is T8 (2 hours)!!!

    full04-03.jpg

    Andy
     
  9. George Farmer

    George Farmer Founder Staff Member

    Messages:
    7,091
    Location:
    Cambridgeshire
    Hi Ray

    That's plenty of light, especially with good CO2 and other nutrients.

    The filter will be ok too. Coupling two in parallel won't double up flow unless you have very clever plumbing - ask Dan Crawford.

    Using two seperate filters would be better, but a single Tetratec EX 1200 should be up to the job. See how you go with one and add another if you experience flow/circulation issues.

    Sounds like a nice set up with those plants too....
     
  10. Ray

    Ray Member

    Messages:
    474
    Location:
    Switzerland
    Thanks guys, sounds like I have a plan! :D

    [​IMG]

    For good filter flow, would people go for option A or B? As I said, I'm going to get the tank drilled, this makes me a little nervous because nobody seems to do that on UKAPS, but the LFS seemed confident about it and Barr and Senske do it for thier clients (and one assumes they can still sleep at night...). There will be 2 directable jets on the inflow which should be enough to get flow all around the tank.

    Snag with A is if you ever want to do a triangular aquascape with a beach at one end it would be hard to hide the intake strainer.

    Sounds like an amusing story, I guess Dan won't be getting the contract to fit my bulkheads! :lol:
     
  11. Garuf

    Garuf Member

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    4,959
    Location:
    Leeds.
  12. Ed Seeley

    Ed Seeley Member

    Messages:
    3,262
    Location:
    Nottingham
    To help hide them you could put both intake and outlet in the back corner. With the jet from the outlet the clean water will then do a complete circuit before being taken in the inlet. As both bits of plumbing will be in the same spot there's onlt one lot to hide!
     
  13. Ray

    Ray Member

    Messages:
    474
    Location:
    Switzerland
    That's brilliant Eds, where would we be without you? You mean like this:

    [​IMG]

    Any reason for that not to work? I suspect flow is not quite so good as right down the tank but hiding is better and I use less tube under the cabinet so better flow in that respect. The LFS finally called me with a quote for the tank today so I will get in there later this week and place the order :D
     
  14. Ed Seeley

    Ed Seeley Member

    Messages:
    3,262
    Location:
    Nottingham
    Yep[ that's what I meant. I have both the inlet and outlet of my Ehiem in the same corner and the water flow is great. Come to think of it my Jewel filter basically does the same as does every internal filter doesn't it, so there really won't be a problem.

    I actually think flow will be better! ;)
     
  15. Ray

    Ray Member

    Messages:
    474
    Location:
    Switzerland
    Thanks all for your help - tank is ordered today. 3 - 4 weeks wait because he doesn't have the opti white glass in stock. I've only asked for opti white on the front and sides - price difference was 174 pounds vrs 205 pounds so it would have been rude not to!

    I'll report back in a journal thread - drilled bottom and opti white glass makes me feel like something of a guniea pig - hope it all works out! :lol:
     
  16. Ed Seeley

    Ed Seeley Member

    Messages:
    3,262
    Location:
    Nottingham
    Sure it will and look forward to the thread.
     

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