Low pH, Alk and Cal OK...

[Octoman]

I've struggled with pH since I set my tank up. It can get as low as 7.7 sometimes. These are my current parameters...

pH - 7.88
Alk - dKH9.2 3.25meq/L
Ca - 400
NH4, NO2 - 0
NO3- <10 (I need to get a higher resolution test...)
Salinity - 1.024

I'm currently using IO salt, I've done water changes once a month, but I'm stepping that up to once a week now - 10% (my Xenia is looking sad). I'm currently using RO from publix - it tests at dKH<1 and pH6.7. I'll have my own RO unit in about a week. I think CO2 in the house might be an issue, I bubbled outside air through some tank water for a couple hours and the pH rose by 0.2.

I've read that a pH this low is not necessarily a big problem as long as Ca and Alk are OK, but my Xenia is looking pretty sad and that might be contributing (it looked fine at this pH for a while, didn't crash until I added a yellow tang - possible contaminant introduced with yellow tang?). All the other corals seem fine.

Any recommendations for getting the pH up? I've been using pH up occassionally that is simply NaOH, I could dose this on a more regular schedule... What about Kalkwasser? Will this push my Alk and Ca too high?

Thanks in advance,
Mark

[Anselth]

One thing to look at is gas exchange. How much effect are your powerheads having on the surface? As corals and fish respire, they create CO2, like we do. If it doesn't escape into the atmosphere, it will result in a buildup of carbonic acid, which will drop your pH.

[bluespotjawfish]

Mark,

What size is your tank?
How long has it been set up?
What's in it?

After you answer the above questions we can better answer if kalk is appropriate for your tank.

Have you checked your magnesium? IO is low in magnesium, and low magnesium can make it difficult to keep other parameters in balance with each other.

The xenia could be reacting to the nitrate. My xenia does just fine with the pH in that range (it is growing like crazy). When my xenia doesn't pulse as much it is usually because of low iodine. But you need to test for that before you add anything since it is toxic to fish if too high.

[Octoman]

55 gallon display, 55 sump,
Running for 3 months,
55 pounds live sand, 40 pounds live rock
1 xenia,
1 ricordea florida,
1 unidentified faviid (large hitchhiker on live rock)
6 small tube coral colonies (also hitchhikers)
1 fungia
2 tree sponges

1 yellow tang
2 firefish
1 watchman goby
1 longnose hawk
1 lawnmower blenny

I don't have a Mg test kit, I'll put it on the list...

Should be a pretty good bit of air exchange between the overflow, the skimmer, the baffles in the sump, and a fan blowing on the sump. I tried bubbling air in tank water indoors for a few hours and there was no change in pH.

[Frankie]

Your not that bad off from what you posted. I would use some superbuffer dKH by Kent marine and start dripping kalk.

[Octoman]

Originally Posted by bluespotjawfish

The xenia could be reacting to the nitrate. My xenia does just fine with the pH in that range (it is growing like crazy). When my xenia doesn't pulse as much it is usually because of low iodine. But you need to test for that before you add anything since it is toxic to fish if too high.

It makes me feel better to know yours is doing fine in the lower pH. I've got some iodine, but I haven't added any because like you said I don't have a test for it yet. I forgot to add a rock flower anemone to my stock list, I'm sure it's using up Iodine as well. I'm not sure if I have much nitrate, it's at least below 10, but it still might be too much. Guess an iodine kit and a new nitrate kit (with a lower range) are going on the list too... What would you recommend for a better balanced salt (with more Mg)?


Thanks FFrankie, I've got some pro-buffer dKH but I was hesitant to use it because I didn't want to push my Alk too high. Maybe with good salt and frequent water changes I won't have to worry about it anyway. I don't have a heavy coral load yet.


Thanks for the help everyone.

[bluespotjawfish]

Do you run carbon? If not, I would use some.

You can increase your alk slowly up to 3.9 meq/l, but make sure you also increase your calcium in relation to this. (And that your magnesium is correct before you even bother.) Here are a few good articles that may help you.

Calcium and Alkalinity by Randy Holmes-Farley - Reefkeeping.com

Low pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com

[Woodstock]

What test kit are you using? Get a second opinion--have your lfs or a local reefer to test it with a different kit. What is the temp of the water? Xenia do not like high temp.
Although I have never had a problem with yellow tangs, keep an eye on yours. Remember that tangs are not always reef safe and yours could be the cause of your ailing coral.

[Octoman]

Thanks for the articles bluespot. Good info!

Originally Posted by Woodstock

What test kit are you using? Get a second opinion--have your lfs or a local reefer to test it with a different kit. What is the temp of the water? Xenia do not like high temp.
Although I have never had a problem with yellow tangs, keep an eye on yours. Remember that tangs are not always reef safe and yours could be the cause of your ailing coral.

For Ca and Alk, I'm using Salifert kits. Oceanmaster by Marineland for nutrients. pH with a calibrated pH meter. I have a marineland Alk kit that I just checked it with, it read 2.25 meq/L. It's expired by a few months, but should there be that much difference?

My temp does run a bit on the high side - usually stays around 82 in the summer. But, the Xenia was doing well and growing at this temp for a few weeks before crashing. It doesn't seem to be deteriorating at all, it even pulses a little, it's just shrunk down really small. (Maybe I should start a new thread just for the xenia...)

So far my yellow tang is very well behaved and eats like a horse, pellets, flakes, frozen brine, and no coral nipping (yet). She does like to nose the other fish around some, but they ignore her for the most part.

[bluespotjawfish]

The temp is pretty high, I'd try and keep it below 80.

What kind of light and where is it placed in the tank?

What type of flow does it get?

Have you tried to rerun the test with Salifert again? Did you get the same results as last time? Did you have someone else run a test for you?

[Woodstock]

I agree with you in thinking you may have a high indoor co2 issue. Open several windows or, if possible, vent your tank with outstide air; have your skimmer venturi draw air from the outside. A refugium would help also!

[Octoman]

Originally Posted by bluespotjawfish

The temp is pretty high, I'd try and keep it below 80.

What kind of light and where is it placed in the tank?

What type of flow does it get?

Have you tried to rerun the test with Salifert again? Did you get the same results as last time? Did you have someone else run a test for you?

Two 48" T5s with individual reflectors ~ 4 inches above water. The top of the canopy is open. I think the real heat generator is my return pump, it's a bit oversized (200W) and I've got it choked down with a ball valve, I probably need to just downsize it and keep that one for a backup. I've also got three maxijets running, two for flow and one for the skimmer.

I ran the Salifert test a couple times and the marineland test a couple times, I could take some water to the LFS, but they use the same brand of kit. There's a guy who lives nearby with a tank, I may be able to get him to check it for me.



Woodstock, I considered running a line to the skimmer, but they drive the mosquito trucks down the street in front of the house. I could run a line under the house pretty easily or possibly out the front door. I try to open some windows for a little while every day, but there's two people, two big dogs, and a cat all breathing out CO2, and the house stays buttoned up pretty tight when were not here.

[prow]

Originally Posted by FFrankie

Your not that bad off from what you posted. I would use some superbuffer dKH by Kent marine and start dripping kalk.

i agree, but i like seachems reef builder instead of kent. only 3 months old tank, your alk will get used up quickly right now.

[Octoman]

Update:

I put a smaller return pump on, temp is holding at a cool 78 degrees.

I tested the iodide and it was 0.

I installed an RO/DI at home on Friday and for kicks checked TDS on my tap water - 160, my RO/DI water - 1, and grocery store RO water - 160...
I think that this may have contributed to my chemistry woes.

I did two ten percent water changes over the weekend and now my stats are:

Iodide - 0.06 (I supplemented a little bit)
Alk - 3.5 meq/L
Cal - 410
pH - 8.02

My xenia is beginning to look a little better also. I'll keep doing weekly water changes.

Thanks for the help everyone!

[sasquatch]

that was a nice turnaround! I guess the temp drop helped quite a bit, I must comment on your excellent responses to questions asked of you, sometimes its like pulling teeth getting the facts, all the best. Steve