Hard Corals Receding...

Here's a question I'm going to throw out to anyone who has experience with my problem, or strong advice to offer regarding it.

I added my Kalk Reactor about a month ago that runs only at night. I have some corals that are thriving off it. However, I have a few corals that are not doing so well. I wondered if there’s something I’m missing, or out of place.

My Calcium level is at 505 which I know is a little high, the Alkalinity tested at 2.75 -3.0 meq/L, and my pH is steady at about 8.2

The corals that are doing well are my Colt coral, Toadstool Leathers, Frogspawn/branching hammer, Green Brain, Acropora, Xenia, Galaxia, Mushrooms, and a few others. I also have some green star polyps that are growing like crazy under these conditions.

However, I have a few corals that are not doing so hot: Pagoda, Cup Coral (which are the same type of coral obviously) Plate coral (receding at the mouth,) Flowerpot (which is receding from the bottom up)(I know that flowerpots usually suck anyway.) These are all hard corals with a skeleton of sorts, but I don’t know why they are receding so badly. Any ideas?

FYI: Some other things to consider is that the corals I'm having problems with are not close enough to any other corals to be stung. I have an 80 gallon tank with 2- 250 watt metal halides, and 2- 110 Watt SuperActinic VHO's. It's been up and running for about 2 years with slight modifications/improvements in lighting, etc. over time. The Pagoda and Cup are placed near the top (possible burning???) and the Plate coral and Flower pot are both in the sand at the bottom of the tank (Not enough light?)

Thanks, Ryan Willden

801-824-4598

Normally, kalk is dripped in the evening.  It has a pH raising effect which counters your tanks natural tendency to drop in pH as the evening progresses.  Therefore, it's very common to operated kalk reactors during the lights out phase.

Ryan, is there solids carryover in the reactor that might be setting out on the effected corals?

I have been running the Reactor at night. pH is lower at night than it is during the day. One of the functions of a kalk reactor is to help stabilize that decrease in pH during "light's off." I tested the pH most recently in  the morning, when I figure the pH would be the highest in regards to running the reactor at night, and I got an 8.2 reading.

Jake, I know the Calcium is a little high, but would you recommend lowering the calcium, or raising the Alkalinity?

Jon, no solids carryover that I have seen. The mix is dripped very slowly into the sump, and then distributed through the main tank.

Ryan

Ryan,

I would say lower your calcium and keep your Alkalinity right where it is.  Although you could raise your Alkalinity up a little I wouldn't recommend this until the calcium level is where you want it.

I guess what I am saying is that I agree with Jon.

I'll try lowering the Calcium level a bit. I don't know that turning off the reactor completely for a few corals, when all the others are thriving is the best answer, but I'll kill it for a couple of days and see what happens. I'm also going to try swapping out the MH bulbs I'm using to see if they are exposing high UV rays into the system. They were cheap bulbs, and may be causing the problem also...

Thanks guys. I have a lot to consider. If anyone is interested in an "all expense paid" (gas money that is) field trip to Stansbury Park, I'd love to have some pointers from some of the Advanced members of our club regarding my particular setup, and water parameters. I've dumped a ton of money into this thing, and it's not going as smoothly as I had hoped...

Thanks, Ryan

801-824-4598