question about new lights

[wannabfish]

Just purchased a 75 gallon tank 3 weeks ago. Had regular flo. lights 40 watt double ballast for the 3 weeks. Since im planning on this being a reef tank, i decided to upgrade lights. went with MH lighting. Today when i came home from work, my tank was bubbling from the live sand. Can anyone explain to me what has happened? thanks

 

[gregvabch]

bubbling? or do you mean the occasional bubble escaping from the sand bed? here and there is normal, it's nitrogen escaping from the bottom of your sandbed.

 

[wannabfish]

When my MH lights are on, it bubbles alot from the sand. when i turn the MH lights off, and leave on only the actinics, after about 5 minutes or so, the bubbling slows, then actually stops.
im very confused what is causing this. heat hasnt changed at all. my tank is still cycling, in its 3rd week. the bubbling seems to be coming from the heavily algaed areas. just giving you as much info as i can so that maybe you will be able to help out with this. thanks again.

 

[gregvabch]

not sure, maybe someone else can help. how long are you running your lights for? you don't need to have them on for very long a day during your cycle, it will only encourage more algae blooms from all the nutrients in the water.

 

[wannabfish]

Im leaving the MH lights on for 8 hours, and the actinics for 10 hours. Im sure the bubbling is either air, oxygen, or as you said nitrogen, im just wondering my the MH lights are causing it to start, and will it stop eventually? am i hurting the cycle at all? any info would be great.

 

[rothdavid]

My guess is nitrogen. Im not an expert but halides are very strong lights and may be penetrating the sand layer which is absorbing some heat and causing the gas bubbles to expand enough to release quickly from the sand.
It sounds reasonable to me... I dont have halides but I do see that after a few hours, the gas bubbles in my sand layer do appear to be bigger than at night when the lights go out.
Lighting length seems very important becuase now I am facing red slime... I left mine on 10-12 hours a day because I have a clam who loves the light.
He may get relocated to my new refuguim which has plant life and a 12 hour light cycle. and them my reef can drop back to 6-8 hours of 4.6 wpg lighting.
Good luck.