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  1. #1
    Senior Member ak_sniper's Avatar
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    Question: Lighting up a 20L

    Hey guys, I need some advice before I make my final descision on my lighting..I plan to have some sps and a clam eventually when my system is stable...

    I plan on having 2 x 75W 24" VHO Super Actinics as well as some MH lighting. At first I was going to go with 2 x 175W MH to make sure the tank gets adequate coverage...After reading up alot and speaking with Ivan....ill most likely have bad heat issues with this setup...So then I started thinking of using 2 x 70W MH OR 1 x 175WMH centered in my canopy, but the cost of using 2 x 70W is much higher than 1 x 175W..

    So now im wondering if 1 x 175 would be enough to cover mostly the middle of my tank with good light coverage for some sps and a clam...and what about the sides...will they get enough lighting from the 175 or will that leave the edges too dark...or would I be better with 2 x 70W ??

    Any help/advice/comments/personal experiences/opinions are appreciated!

    AK

  2. #2
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    I have one 250W MH and 2 T5 actinic over my 20G and I find I have to keep the MH fairly high off the tank (about 10") to keep it from reaching a rolling boil (lol). I think you will find that one 175W MH will cover the tank quite well. After I get my 14K ARC bulbs from Ivan (shoudl be here any day) I plan to only use the actinic for dawn & dusk lighting. HTH.
    35Gal mixed Reef with light fish load. 250W MH, Jebo Skimmer,

    100Gal FOWLR- Heavy fish load and a few soft corals.

  3. #3
    Senior Member ak_sniper's Avatar
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    Im guessing you have your MH at about 10" then :P

    When you say a rolling boil, hehe, like how high you think the temps could go up too ?? And did that happen to yours ??

    Cause ive got my canopy built already, when i install my MH lights, ill have about 4" of clearance between lights and water, but I have enough room to install some 120mm fans so I plan on putting at least 1 on each end (maybe even 2) and maybe another 2 or 4 on the back side of canopy, some will draw air in and others will push out...

    Think with a few 120mm fans pushing above 50-60cfm each will give enough air flow to keep temps low under the hood and water ??

    AK
    20G Reef Tank (Starting again...)

  4. #4
    Moderator Krugar's Avatar
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    Plan on an auto top off. You'll loose a lot of water to evap either from the heat of the lights or the air movement of the fans or both.

    Since putting an MH over my 10g, I'm loosing enough evap daily to raise my SG half a point.

    Cheers!
    There is nothing so permanent as a temporary measure.

  5. #5
    Senior Member ak_sniper's Avatar
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    Good advice Krugar, that also was part of my plans :P I will have to work out a auto-top off circuit cause I plan to use 2 x Float switches, where one controls the lower water level and the second the upper water level so the system will start topping off when the water goes down a bit and stop when it reaches the top float, just so i dont have my pump start often and run only for a few brief seconds...

    But as for the lighting, SPS/Clams, think they would get nice colors/survive good on the sides of a 20L with a 175W centered or am I better with 2 x 70W??? cause my lights won't be at about 10" from water but only like 4" so im afraid to get a spotlight effect on the tank if I use one big MH rather than 2 smaller MH...

    Anybody else has any opinions/suggestions ??
    Its still appreciated

    AK
    20G Reef Tank (Starting again...)

  6. #6
    liv
    liv is offline
    Former Moderator liv's Avatar
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    a MH usually covers 2x2feet..so if the top of your tank is about this size.. i'd stick with one.... and lots of fans

    moving.. so temporarily out of SW :b8:
    planning next tank, possibly 60x30x20 on 2x plasma.
    updated: 2011/05/30

  7. #7
    Senior Member ak_sniper's Avatar
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    Yeah my tank is 30"x12"x12", so with one id be good eh, nice thats what I was hoping :thumb:

    I can get a bare ballast (no casing) for a 175W MH at LiteMor in Ottawa for 69.99 I believe I was quoted and for 10$, so with an ARC bulb from Ivan and a socket and my DIY reflector I think ill get a pretty good MH setup for not too much $$


    As for my VHO's, 2 x 75W Super Actinic will be just fine im guessing ??? Well, since no one mentioned anything bad about em :P

    AK
    20G Reef Tank (Starting again...)

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