Adaption to pH?

[sjw017]

I currently have about 35 total specimens, mostly hard and shrooms, no SPS.

I had not added anything in almost 1 year, only major change was use of Ca additive instead of kalk for 8 mo. I replaced the MH bulbs 4 mo ago. Prior to that, the major change was removing the agragonite bed in favor of sand 1.5 yrs ago.

The problem is that my pH was constantly 8.25-8.5 and began to precipitously decline to around 8.0 with no visual signs of stress.

After the bulb change I lost a 3 yo chondy and figured the lights burned him. Well I have recently added 3 new specimens, a galaxeia, plate and xenia frag. All three are showing major signs of stress and starting to die off in the last week. A check of the parameters was alarming, pH 7.61 (daytime), dKH 9, sp gr 1.025, Ca 400 and all pollutants below threshold levels.

I am pretty lax about the parameter measures, I like to watch the corals and see how they look. All of my longterm specimens are
great, fully extended and budding like crazy. Any suggestions??

See my profile for tank descrition.

Shawn:

[Randy Holmes-Farley]

Shawn:

Personally, I'd suspect that the pH measurement is off somehow.

If the pH is really 7.6 during the day, then IMO, that is a substantial issue that you need to correct.

What type of alkalinity supplement are you using? If the pH is correct, you should switch to an alkalinity supplement that has the effect of raising the pH. I can provide a list of these (or you can scroll through previous threads in this forum on low pH) but it's easier to prescribe a solution if I know what you are using now.

[sjw017]

Your telling me it's problem!!!

I am using seachem products for all of my additives except Mg and KI.

I ran a little test (vigorously aerated a glass of water for 2.5 hrs) to see if the low pH was a function of CO2 retention. The pH still 7.67. I also found a snail shell stuck in the skimmer inlet!

I am going to go back to dosing kalk, I think, my pH was always stable with that and it is alot cheaper.

I was just more curious if the corals would adapt to a low pH, or I might have something else going on. I hate to lose new additions, gets expensive and frustrating.

Shawn

[Randy Holmes-Farley]

I was just more curious if the corals would adapt to a low pH, or I might have something else going on. I hate to lose new additions, gets expensive and frustrating.

I saw that in the title, but you didn't ask it in the body, so I didn't think it was what you were really after.

No, I do not believe that corals "adapt" to low pH. They might survive it, but it is clearly a stressor to them.

FWIW, calcification declines in corals with every drop in pH below normal.

[sjw017]

I am not even sure if I had a real question. I also thought the monitor had to be wrong, but it was'nt. I just did not expect my coral to be living at that pH, much less thriving.

I tried to supply as much info as I could without making it long, hoping someone might have had this same effect.

It wasn't until I stopped kalk that I developed a prob, but this was also about 6 m after I swapped out the aragonite.

Thanks

Shawn