Bulb replacement

[DEEPBLUE]

Is there a way to know when MH bulbs need to be replaced?

[miller]

usuall time frame is 10-12 months

[rocko918]

also depend on what type, MH , VHO, PC, T5?

[Caribbean Jake]

yes, when corals start to contract and glass starts to fill with brown algae, and it has been more than 8 continuous month of light source usage, then it is time to consider replacing the bulbs.

[Lee Stearns]

I was at the 14 month mark on my MH 10Ks and the only note I have is that coral growth slowed a bit- and it was not as "bright" of a tank as it used to be. No big algae blooms- but then I have 440 watts of VHO actinic supplementing the two 250 watt DE 10 K ABs.

When I changed out the 10K ABs the Par value doubled as measured by Howard and our clubs light meter. I gave the new bulbs a three day acclimation by keeping the canopy open- which raises the bulbs about 4 inches more and angles the light a bit, But then I was only running my MHs about 6 hour a day for the last two months- Might have made the acclimation easier, and might have been a contributor to the "slowed" growth noted in the corals-

The tank LOOKS BETTER with the new bulbs- so I guess it really depends on preference, length of time each day you burn them, as to how long before changing- I hear a lot of folks saying lighting is critical in how their tank blooms or not with algae. I believe it is much more nutrient driven than light driven- seems more newer lights would fuel growth - I know the argument is spectrum- as the bulbs burn they lower the spectrum output from say 10K bulbs now shifting to the 6500 K range and stimulating things like algae that grow better in that range. I guess this all could be true- I just have not seen it to be true in my aquarium. I do know that the many folks have had different species of Coralline Algae take over as the older pink variety that thrived under the old lights bleached under the new lights.

Again I have not seen this in my tank but have seen that in other tanks.

[Caribbean Jake]

The best way is to keep a LOG.. (how many times have I say this), and write down in your log the date the bulbs were installed together with the type and kelvin of the bulbs, and the duration (how many hours per day). This will help you track the age and when it is time to change.