Well you can go with lower par bulbs. Then you can also raise the fixture. As well you can go with 6 bulbs instead of 8. Shade screens would work as well. 400 par not lethal to sps or some lps. You can run light for shorter period. Instead of eight hours you can run them full blast for 4 hours. The drivers are not over driving bulbs as I have tested them. They are correct drivers for the bulb. Just reflectors do a really great job. I would stay away from dimmable just because it's not controlled with apex. You only can dim on two channel. 2 bulbs and 6 bulbs channel.
Thanks Jonnyu. Great information. Can you or anybody else take a crack at a few more questions ?
- Can you name a few lower par bulbs? Never seen that advertised, in fact never seen PAR numbers listed even on ATI. Are we talking 10%, 30%? I like ATI tubes, I wonder if I can find the same spectrum choices?
- Does less "ON" time equate with less PAR from the coral's perspective? In other words lets say we have 500 PAR & it's 20% too much on a 10 hour light schedule. Would lowering the light schedule to 8 hours be the same thing as lowering PAR to 400 ? Something tells me there's a difference; it's not a linear relationship. Correct? ? I really want to run lights for more than 8 hours - I want more like 10 which I have now.
- Following up on the question above. Would a light schedule incorporating just 4 of the 6 bulbs for a large part of the day decrease PAR in a way as to give me more flexibility with lower light corals? Something tells me it's all the same if the sensitive coral are mounted directly under the 4 bulbs. Correct?
- I don't want to forgo the possibility of APEX controlling the lights if I go the dimable route. But it's doable for me as I'm OK with a simple timer. Does dimming or a constant setting of less than 100% wear out bulbs or ballasts early?
-In my case I can't raise the light fixture beyond about 6"-7" to control intensity. So I what's the best remedy (A) Remove or partially disable the refectors (B) Put plastic window screening or something else under the lens (melting? Seems primitive) (C) Use a 4 foot fixture on a 5 foot tank. LPS can go on the sides & my understanding is shorter bulbs give off less PAR even under the middle of the tube. Comments?
-Maybe an ATI fixture is just not right for my needs. I want the quality, but if I can't keep the corals I want it's just an expensive piece of junk. I have a nice collection of LPS chalices, favia, scoly, Goni etc alongside montis, stylos etc that must migrate to the next tank. But I don't want to kill everything for the sake of growing some acros.
Any suggestions? What would you do? What less powerful fixture would you recommend? Or "derate" the ATI as described above. Maybe forget all T5 altogether & go with a BML LED strip & 2-4 T5 retro kits hybrid.
Thanks for any ideas, comments or experiences you can share.