Need help with pH problem!

[nickbuol]

I finally got the stand built for my wife's new 30 gallon tall tank, put some new argonite in the bottom (after rinsing it of course) put in about 75% freshly made R/O water and salt mix (mixed it before putting into the tank), and 25% of water from the main tank. I have the heater and powerheads going. I put some of the live sand (just a couple of scoops) from our reef tank and a piece of live rock. I tested it, and everything was good. No ammonia, nitrites or nitrates (of course). Temp was good at 72F. pH was at 8.1
That was right after putting everything in. Well the next day I starting seeing a lot of dead critters that came out of the live rock and/or sand. Many little shrimp like critters, some worms, small feather dusters. All dead. Some other critters were doing fine. I thought it was because of the move to the tank, and part of the begining of the cycle. Anyway, it has been 2 days since I put the live rock in, and I took it back out today and put it back in the main tank. The pH tested the very lowest on my test kit (6.0 or lower) yesterday, so I put in "Proper pH 8.2" which after the recommended dosage, the pH was still off the charts on the low end. When that happened again today, I took the live rock out.
What is going on here? We did not have any lights on the tank until tonight (after the live rock was taken out). I heard that lights can effect pH, so maybe that was it. Any ideas?
Did I kill the live rock?
I did a search, but go a ton of messages that are abotu everything but a pH problem. Such as "what are your water parameters, temp, pH, etc".

 

[kris walker]

I'm sure it wasn't the lights.
However, I am uncertain what the timing of things are in your post. Don't take offense, I just can't follow all the jumps back and forth. What day of the week did you put in the LR? What day did you take it out? What days were the tests?
sam

 

[josh]

Hi,
Ok I think I got all the info. For starters the temp is way to low, you should shoot for 80 maintained. The pH being at 8.1 is no big deal, although I am sure if that is what it actually is being you said later on it was off the scale low. So, in general you pH will be lowest in the morning, but shouldn't get below 8.1. Also you mentioned proper pH of 8.2, well the pH of NSW is 8.3... so try using seachem reef buffer it will help with the alk as well. I would start by taking the water into a LFS and getting a complete tests, including metals and so on. Then you will know more what's going on.
HTH
Josh

 

[josh]

Well, I just re-read the post, you said the pH was below 6.. that will kill most things in a hurry. That sounds like the problem, just dose the buffer daily till things are back to normal. I am not sure though how it got that low in the first place... THe salt acts as a buffer, but apparently not enough.
Josh

 

[broomer5]

Did you set up this 30 gallon tank in one day, add the substrate and saltwater, heat it up, added a couple powerheads, and then immediately add the piece of live rock and scoop of substrate from your main tank ?
How long did you mix/aerate the new mixed saltwater ?
If you added all of this on day 1, chances are that the saltwater had not yet reached a carbon dioxide CO2 / oxygen O2 gas equilibrium, or state of balance between the two gasses.
In other words, your saltwater may have had an excess of CO2 gas in solution and not enough O2 diffused into it yet.
This can happen when saltwater is not mixed and aerated with a powerhead for several hours. Many people will mix it overnight or more.
To compound matters worse - newly mixed saltwater is considered a little caustic. But the biggest problem is it does not have much buffer capacity. Even though most manufacturers of salt mix do add various salt carbonates and bicarbonates, it's not normally enough to provide much buffering, high enough alkalinity to help maintain the pH.
Excessive CO2 in solution will naturally form carbonic acid - very acidic compound - and will cause a major drop in your pH - to the magnitude that you described. Unfortunately, most sea critters can not hang on when the pH drops that low
Lighting only affects the pH if you have photosynthesis occuring within live plants or algae, or fish that are more active during the day vs resting at night.
Not sure if you killed the bacteria on the live rock, but as you said, the worms and pods didn't survive.
Sorry to hear of this - but it can be avoided by mixing your saltwater for 24 hours with a powerhead, prior to adding it to a tank. Or on a new set up such as yours, after adding the saltwater to the tank - wait a day or two for the tank water gasses to balance out before introducing any life forms to the tank.
If you DID mix the saltwater overnight or for several hours - then I am stumped.
Add buffer to increase your pH slowly over the next several days / week. Provide plenty of circulation - it will work out eventually.
Agree with Josh - you may want to bring your temp up several degrees F.
Brian

 

[nickbuol]

The water was fresh R/O for 50%, made right then, and salt mized right then. 25% was a salt wix from the 9th of January sitting in an air tight container, so pretty much "fresh", and the last 25% was from the reef tank.
The temp is now 76F, and I keep the reef around 80F during the day (thanks to high power lighting, I can't get it any cooler even if I wanted to). I will bump up this tank a few degrees.
I will also add an air stone to the mix. I know that it doesn't directly add oxygen to the saltwater, but it adds more surface movement.
I've heard of people using baking soda as a buffer. I might try that as a low cost way to get things up where they should be. Actually, it was my mistake. The lowest pH on the test kit is 7.4, and I was a hair above that. Now, it is looking like about 7.8, so it IS on the rise.
It would still be nice to know if I killed the live rock.

 

[jlem]

I can remember when I started using ro. the water was so pure PH-7.0 That even with the salt mix it would get a ph of about 7.8. I mixed some salt with tap water and wallah ph 8.2. So now I buff my ro water before it goes in the tank. I use baking soda, but word of caution, baking soda is very potent so use sparringly

 

[fshhub]

did you test your alk, RO water has a habbit of dropping your alk, which if that is not in line, you can add ph increaser til you are ready to find another hobby, you need to get that up in line, if that is not in line, you will never be able to keep our ph stable(where as, you will test it today nd it'll be fine, and in 2 days, back down where you started), and you very well may have killed nearly everything in the rock
HTH