Alk trouble!

[Mike&Pam]

My alk has been dropping rapidly. Calc and ph are fine. I only have 5 corals and lots of live rock and sand in my 90 gal reef. My corals aren't looking so good because of it too. I have 2x96 watt pc's. I assume the problem is the alk. I don't know what's causing it to drop so much. When I raise it using reefbuilder, it just drops again. The only thing I have not tested for is magnesium which I've read plays an important factor. What type of test kit should I get to test for magnesium? I use red sea test kits and would preferably like to know if they make a mag test kit since I'm used to their procedures. But any one reccommended would be fine. Also, should I raise the alk with the seachem reefbuilder I have or reefbuffer (which I would have to buy)? I plan on acting on this immediately since my red sea alk test shows that it has dropped almost below 1 meq. Thanks everyone.

Mike

 

[jdeets]

For testing Mg, Salifert makes a good test kit. If you're doing regular water changes, low Mg is unlikely, but you still need to rule it out.

What is your Ca level? Salinity/SG? Have you noticed any significant fluctuations in Ca level as your alk has been dropping? Where did your alk start and where is it now? How old is the test kit? Have you verified the test kit results by taking a water sample to the LFS for testing?

I'd recommend Kent Superbuffer dKH to raise alk once you verify your test kit. I've used it before with good success.

Don't overdose the buffer--it took a while to get low, so expect it to take a while to boost back up.

Have you noticed any increase in coralline algae growth lately? With only 5 corals, any rapid depletion that is occurring probably wouldn't be from the corals, but coralline algae could certainly do it.

 

[Mike&Pam]

My tank has been running for almost 7 months now. The calc is at 450. There have been no fluctuations in the calc, just the alk. So, I should raise it with a buffer rather than the reefbuilder I am using or will either do? I've raised it with the reefbuilder before over a period of several days (2 dosages a day, raising it at 25 meq each dosage to keep it gradual). I've had to do this several times in my tank. After a few days or so, I test the alk again and it drops significantly. I use the reefbuilder to maintain the level as well. As for the test kit, I take a water sample to the lfs to have tested and they come up with the same thing because they use the same red sea test kit.

 

[Mike&Pam]

To answer your question about my coralline algae, I have not noticed anymore growth except for on the sand. It gets completely covered in thick, purple layers. I have to stir it to clean it. I don't get any on my glass, just on the sand. I used red slime remover because red slime (cyano bacteria) and the purple algae were taking over the sand completely. The treatment totally wiped it out, but one week later the problem was back. My phosphates are at 0. I tried treating it again but the problem just came back a couple of days later. So, I have this problem and the alk problem.

 

[jdeets]

What about your other water params? Any nitrates?

What is your bioload and how much are you feeding the tank? How many "fish inches" do you have in the tank?

The combination of the two problems you describe leads me to believe that there is an excessive nutrient input, and as excess nutrients break down, they create acidic byproducts that are being nutralized by the buffer component in the system. Overstocking is also a possibility, as the acidic component of tank waste. Excess DOCs are fueling the cyano growth. Just a guess, but since you have these problems in tandem, that's why I ask.

Also, what kind of skimmer are you using, and are you getting good production of dark skimmate?

 

[Mike&Pam]

I have not noticed anymore growth except for on the sand. It gets completely covered in thick, purple layers. I have to stir it to clean it. I don't get any on my glass, just on the sand. I used red slime remover because red slime (cyano bacteria) and the purple algae were taking over the sand completely. The treatment totally wiped it out, but one week later the problem was back. My phosphates are at 0. I tried treating it again but the problem just came back a couple of days later. So, I have this problem and the alk problem.