light hight

[marteny]

I bought 2 250 metal halide for my 68 gallon tank. the directions do not tell you the hight to hang the lights. lrs say 6, while others say 12 inchs from water. Which is best, I want to grow sps in my tank. I also bought a chiller so heat is not a problem.

 

[TCUguy]

1) You need to get a PAR meter.
2) If par doesn't exceed 600 at the top of where your corals will be, and if you water doesn't overheat, then anything as close at 4" is fine.

However, if your at 4" and the tank starts heating up OR par exceeds 600 at the top of your corals, then you need to raise it. Also remember, the lower, the less light hitting your glass (which is good, because it means less algae growth on the glass and less cleaning )

 

[bimmerzs]

I would go 8"-10" as this allows you to get some air moving between your lights and the waters surface along with preventing any splashed water from cracking/busting a bulb. Even if you have glass shield's on the lights it will keep salt creep from coating them which would reduce the light reaching your tank. Other than that just remember to place coral's according to their light tolerances, and to also slowly acclimate your coral's to the light and you will be good. Remember.....the sun will never be replicated in our tank's. [smilie=lol.gif]

Cheers,

 

[marteny]

Thanks for the help, I will probably keep it around 11-12 inchs and slowly add 30 minute to the time, until I get the time back up to 8 hours. Once I get it there i will either buy or borrow a par meter and adjust it from there. I don't know why the pros could not tell me this, it seems pretty simple. This is why I am on the web site all the time. [smilie=clapping.gif]