Low pH and high/good alk

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Biggen

Aquarium Advice Addict
Joined
May 8, 2003
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Hey guys. Quick question regarding my new tank.

Just took some readings to check pH and KH (alk) in my newly set up tank.

Alk comes out at 10.5 dKH
pH comes out at ~8.0.

Do I need to be concerned about this pH at all? I know it is a tad low when compared to sea water. My LR is coming in on Thursday and that will start the cycle for me.

Do I need to adjust this pH to 8.3 before my LR comes in or should I just let it be and let the tank cycle? If so, after cycling, then should I adjust the pH up to 8.3 if it is still low??

Using Instant Ocean salt and Aragamax sand. 40 gallon tall...
 
Do you have any substrate? This will help your ph. IMO I really don't see a problem I too had an 8.0 reading for ph, and I added live rock and it was ok. the preferred of ph is between 8.2-8.4 So it isn't like your way off so I wouldn't worry.
 
the preferred of ph is between 8.2-8.4 So it isn't like your way off so I wouldn't worry.

Just a FYI, PH is logorithmic, each 1.0 rise or fall in ph is ten times more alkaline or acidic respectively. So a difference of .2 or .4 is 2 - 4 times more alkaline than the 8.0 your working with now 8O

Do you have any substrate?

This is really a misconception. Aragonite substrate will not buffer above 8.0, for it to buffer higher than that the ph would have to drop drastically low to dissolve enough aragonite.

All that said, without knowing the CA reading or Mg, it is very difficult to say whether the ALK is good or not. It appears to be, but without the proper CA reading, it may be way off. Most likely the cause of the lowered ph is increased CO2 n the water, try creating more turbulence at the surface or even pumping air in from the outside to increase o2 levels in the tank.
 
All that said, without knowing the CA reading or Mg, it is very difficult to say whether the ALK is good or not. It appears to be, but without the proper CA reading, it may be way off. Most likely the cause of the lowered ph is increased CO2 n the water, try creating more turbulence at the surface or even pumping air in from the outside to increase o2 levels in the tank.

Ok. My CA and Mg test kits are coming in this week. I will check those levels as soon as I receive them. I did not know that CA and Mg had an effect on Alk at all. Guess I need to head back to the research room.

There should be plenty of surface turbulence between the two ph's and the return pipe from the sump.

Dunno what it is....
 
you say to add air to you tank if you ph drops? did i read that right? if so how much air is to much air and would that raise my ph! if it is low say 7.8
thanks michael
 
Increasing oxygen to the tank, is usually the first thing you want to do when having a low ph problem. This can be accomplished by increasing surface agitation of the water.
 
I still haven't gotten in my calk kit. But at least I understand the relationship between Mg, Calk, and Alk now.


Just put in my 45# of LR this morning. The cycle is starting... :mrgreen:
 
what if i was to use the ventrie air set up on my filter to put air bubbles in the tank is that a good idea?
 
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