Will darkness kill hair algae before corals?

[iamwhatiam52]

If I place a rock with air algae and corals in a dark sump, will the algae die off before the corals?
For that matter, will darkness ever kill off hair algae without leaving remnants that can grow back?

[reefnetworth]

darkness will not kill hair algae or (red) cyano. PO4/phosphate is the food which it lives on. if you have good water source such as an RO/DI unit it will go away. pinching it back helps temporarily, but if PO4 is still available to feed it, it survives.

[reefnetworth]

darkness will not kill hair algae or (red) cyano. PO4/phosphate and NO-3/nitrate is the food which it lives on. if you have good water source such as an RO/DI unit it will go away. pinching it back helps temporarily, but if PO4 & NO-3 is still available to feed it, it survives.

[Sk8r]

Create a fuge in your sump. For your water volume, it would take about a 30g fuge lit 24/7 to totally blitz that algae in a couple of months.
TO answer your question: make a practice of turning the lights out on your tank 3 days a month, one day of actinic only, back to normal. Running phosban or operating a fuge during that three days will suck up some phosphate from algae dieoff. Eventually you'll get it.

[iamwhatiam52]

I guess that was the answer I expected. Fix your parameters and the algae will not thrive.

But even with nitrates and phosphates, it seems like without light a photosynthetic organism would waste away.

RO/DI and a fuge are already in place, the phosban is being set up.

[Lucky-rc]

I killed algae like this once... But i had no corals at the time and the lights out spell went for about a week and a half. Nothing else seemed to be hurt.(Purple-pink-and red coraline)
Also, to give you something other than the expected responce...
I have found that the rocks that can be flipped over, Turn them over for a week or two this works If you have a phos. reactor being set up, I would try to keep my flow as high as I could (current in the tank) And manually remove as much algae as I could. This also helps.
Remember...(I was not told this) When your phos. reac. is up and running, set the flow coming out of it to where it reads -0- phos. keep it like that (flow wise) Now this reading will change maybe with in a week or two. But don't change the flow... When the flow coming out of the phos. reac. (rises) maches the tank reading change your media in the reactor.... From this point keep the flow out of it at -0-
I'm not sure as to why the first charge should rise like that but that is how I finally killed off my algae problems. This will take some time though. Your manual removal obviously will speed it up.
Good luck.

Lucky
Lucky