mh lights


:notsure: :notsure: how long would you leave your mh on per day we are getting lots of algee


Active Member
How long are they on now? Back off a couple hours and see if that helps.
Mine are on for 7 hours each. The atinics are on for 12.


our mh come on at 2:00 pm go of at 11:00 pm blue actnic comes on at 9:00 am goes of at midnight moon lights come on at midnight go of at 9:00 am


yes, that should be fine. keep in mine lighting is not the only thing that cause algea. do you use ro water? how about your clean up crew?


yes we use ro and we have 3 emerald crab 4 porclin about 25 red leg 25 blue leg and 50 asorted snail 6 starfish 2 coral banded and 1 saron shrimp


also how old is the tank, alot of newer tanks go thru stages where different algaes are growing and as the tank matures they die off. also test your po4 levels.


Active Member
I keep my MH on for only 5 hours and then my VHO takes over from there. Right now I'm going through a Cynobacteria problem cause I added some new sand so I hope I can keep it down and hopefully it will go away soon.


Active Member
Same here, Kip said alge is the first thing to happen when you introduce new lights. :yes: I have cut it back to 4hrs until its all under control, then I will slowley increase time.


Most of the species of corals found inside a reefers aquarium come from zones located inside the Tropic of Capricorn and Cancer. Inside these zones, sunlight is guaranteed to be about 12 hours per day. By limiting the amount of light to your specimens, your basically starving them of one of their vital food sources. Personally, I would never tell anyone who houses corals, to go any less then 8 - 10 hours of light per day, minimum. Instead of limiting their food source, you can always raise your lamps higher, by about a foot or so and then slowly drop the level a few inches per week until all inhabitant are acclimmated. Another suggestion is to place a few layers of fine mesh vail in-between your lights and the top of the aquarium. After 1 week, you can remove a layer of vail until all of it has been completely removed. This will absorb light intensity enough to where your corals will be content and still prosper.
Low frequency, long wave length light is a precursor to a bad algae break-out. Oh course, fueling the algae with a high consentration of PO4's and a large build-up of DOC's will only insure that a rough time is ahead. Algae needs more then light to survive, so one must look at other reasons why the outbreak has occured. One that must be acknowleged and dealt with properly to rid yourself of the nusience. A chem check with a good test kit is crucial in determining the cause.
A good reference to check are:
Calc and Alk levels
Mag Levels
PH (am & pm)
Borate & So2 (if available)
Ammonia, Nitrate & Nitrite
If your running a skimmer, is it producing skimmate frequently, or occassionaly?
Feeding habits, quantity, and variety of foods
Type of H2O added
Look and smell of the overall system
All of these items listed above can help you figure out your aquariums status and overall health.
Personally, I never do water changes. Except for the occassional quarterly 5 gallon replacement of new salt water, to replace supplements that I can not easily obtain. I DO NOT sugggest this for ANY NEWBIE entering the reefing world. Experience and time will dictate how your husbandry will evolve. Remember, coralline algae is a great barometer of a healthy, thriving system. Time and Mother Nature will do the rest.
I hope this helps...