question about new tank and ph???

[Lynn]

Just got my tank set up. 180 with 300 pounds of aragonite and 100 lbs of LR. I made RO water. Its been running for a week now. The PH is only 7.9 and Alk.=6. Cal is 250 What should I do?
The strange thing is that I set up a 20 gal about 6 months ago and used the same water etc. That tank has been right from the start 8.4 ph 2.5 alk. and 550 cal??
Thank you so much, Lynn

 

[AF Founder]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Lynn:
<strong>Just got my tank set up. 180 with 300 pounds of aragonite and 100 lbs of LR. I made RO water. Its been running for a week now. The PH is only 7.9 and Alk.=6. Cal is 250 What should I do?
The strange thing is that I set up a 20 gal about 6 months ago and used the same water etc. That tank has been right from the start 8.4 ph 2.5 alk. and 550 cal??
Thank you so much, Lynn</strong><hr></blockquote>

Lynn,

Did you use the same salt, and was the live rock cured?

Terry

 

[Lynn]

yes, I use instant ocean both times. And both times the rock was cured.
thanks Lynn

 

[jamesw]

Hi Lynn,

What about the salt you used? If you mix a batch of synthetic seawater using old salt which has been exposed to the atmosphere for quite some time, you will get low calcium and alkalinity. That in turn will degrage your buffering system leading to the low pH you are seeing.

This is because the Ca and CO3 can react in the salt mix to form insoluble CaCO3. When you mix the salt you will see white power or nodules left in the mixing container in the bottom. This has happened to me in the past, so I hope you can appreciate this advice.

Have you tried adding a big slug of Kalkwasser or a 2-part additive to the newly set up tank? If there's nothing alive in there (remove the liverock) you shouldn't have any problem doing that to bring up your ca and alk.

HTH
James Wiseman

 

[Lynn]

Anybody out there to answer my question??
thanks Lynn

 

[flameangel1]

Hi Lynne,,
Just a thought here--if you were using the same bag or bucket of Instant Ocean for both tanks-
did you mix the salt mix well when you opened it??

I have found that many salt mixes will "settle out" (similiar to a box of cereal) during shipping etc.
(for example-higher alkalintiy in the top of the bag and lower at the bottom of the bag).

That would account for the opposite results you have in your before and after uses.

I now mix the dry salt well when first opened, before using any of it.
(done by repeated pouring it into another container)

 

[AF Founder]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Lynn:
<strong>Anybody out there to answer my question??
thanks Lynn</strong><hr></blockquote>

Lynn,

Another question: did you make the artifical seawater by adding water to the salt or adding salt to the water? It makes a big difference. You must always add the salt to the volume of water that you want to make.

Also, try putting some of the new seawater in a jar and aerating it for about 1/2 hour, then check the pH. If it is now up to 8.3 or 8.4 then your new aquarium in insufficiently aerated, and not getting enough CO2 out of the water.

[ April 24, 2002: Message edited by: Advanced Aquarist, Editor ]</p>