coral problem

[Pkelley228]

Recently my corals have started to decline. My Monti Cap, and Acros are losing color and starting to bleach. Water parameters are decent with:
PH - 8.0
DKH - 6.1
ALK - 2.25
CA - 400
MAG - 1275
NITRATE - 5
NITRITE - 0
AMONIA - 0
COPPER - 0
SALINITY - 1.024
I do Monthly water changes (due for one), utilize carbon, and run a skimmer(which seems to be working fine).

Good flow in tank, and all fish and other livestock seem to be fine including zoanthids and frogspawn.

Have started to get a bit of an algae bloom and was wondering if my lights could be the problem. I run dual 250 20k MH, and a 150 20k MH. Bulbs are probably 11 months old.

Could the need for new lights be causing the coral problem?

Any input would be great. If you do think that the bulbs could be causing the problem, where do you order your lights from and what would you suggest for best growth and color from the above listed coral?

Thanks

 

[Markk96]

11 months is really pushing it for MH lighting. I would say that could be the main issue.

 

[Pkelley228]

Any suggestions on bulbs for best growth and appearance?

 

[breutus]

A couple of questions for starters, how long has the tank been setup? and how long have the declining corals been in the tank? do you check your PH often? 8.0 is a little low, I try to stay in a small swing of high 8.1 to low 8.3. and I could see this possibly causing a problem.

and my thoughts on lighting are, it could be declining lights it might not be LOL it's hard to tell without a par meter to see if they have declined seriously and suddenly, but I have seen it happen at the year mark before.

 

[Pkelley228]

Tanks been up for about 20 months. I have been checking PH alot lately due to problems. It has stayed steady at 8.0. I do have some PH buffer, but am hesitant to put supplemental chemicals in unless absolutely necessary, and I really haven't spoken to anyone that uses it. Have been considering kalk reactor, but finances a little tight for that right now.

 

[JxMetal]

TDS of top off water?

 

[Pkelley228]

Was a 4 last time I checked. Just changed membrane.

 

[JxMetal]

when mine gets to 1 the tank begins going downhill

 

[Reggae Fish]

Phosphates? Did I miss this? I might have read over it...Are you running phosban and did you test for it?

 

[Lost His Marbles Name]

Mine was going down hill until I quit using I.O. and went back to corallife and changed my phosband media. Everything is now preety and growth is better. I would agree with getting new lights and a cleaner crew but I'm crazy anyway so why listen.

 

[DrBDC]

I'd probably bump that dKh up to 7-8 if you run some form of automatic supplementation i.e. ca reactor or kalk reactor/topoff. If you manually supplement the ca/alk I'd go to about 9 or 10 so that it stays above 7 as it is consumed. This will also help maintain the pH. You may be having a pH drop at certain times of the day when the dKh is below 7.

Keeping the tds down at 0 makes a difference too. I can see issues if I let it get up to 1 or 2.

 

[Pkelley228]

Well I did just change the membrane, hopefully that will bring tds down where it should be. I also ordered new bulbs, 2-250 15k and 1-150 20k. Currently I am not running any media, but I will supplement the alk and ph to see if it helps.

 

[DrBDC]

Just bring the alk up but don't add anything specifically for pH. 8.0 is fine especially in the winter with the house closed up more.

 

[Pkelley228]

Thanks for the advice, and I will give it a try. Anyone have a link for a diy kalk reactor? Looked on the diy forum and didn't see any.

 

[DrBDC]

How do you top off evaporation and ca/alk now?

 

[Pkelley228]

Auto top off from a 30 gallon trash can that I fill with fresh ro/di weekly. I don't currently add any ca/alk, and was going to add a alk supplement that I just purchased last week.

 

[Pkelley228]

Well, good news and bad news. New bulbs arrived today. Broke one putting it in. Guess I'll be spending some more money today, and ordering a new one. I do like the look of the XM bulbs that are in and working compared to the old one that is still installed. I seemed to have a real hard time pushing them up into the socket and one of the ends broke right in half, all the way into the bulb.

 

[DrBDC]

What brand of salt are you using? I'm curious as to the starting ca/alk levels.

 

[Pkelley228]

corallife salt is what I have always used.

 

[DrBDC]

Have you been having to do any alk supplement? Ca on coralife is much higher than your tank is testing. For every ~20 ppm of calcium used, it will use 2.8 dKh of alk. When one gets low it will throw the numbers out of wack and slow/stop calcification.

If you haven't been dosing anything, kalk would probably be enough to keep it stable for awhile before you would need to go to a more expensive method. Especially if you already use a top off resevoir (depending on the topoff setup).

I would bump your numbers to a chosen level, then either determine the two part supplement needs or start adding the kalk. If you want more info on two part supplementing I can post some links. Keeping the ca/alk stable is so important.