pH

[SigEpLucas]

My pH has been around 7.8 to 8.0 since i've set up my aquarium, I understood at first it could have been low because of the high ammonia during the cycle but my ammonia has been 0 now as well as my nitrite and i'm still showing a 7.9.

Is there anyway to bring this up a bit or is it not a big deal?

 

[messiah023]

Sig,

You should test your PH just before the lights go out.
Also, you may want to get a 2nd ph test kit (just to be on the safe side).
Sometimes, test kits are wrong. Pick yourself up a nice Salifert kit for ph.

If after all this, your ph is indeed off, you can start buffering your water with an alkaline buffer like THIS one from SeaChem.

Good Luck!

 

[Bifferwine]

Like messiah said, pH fluctuates during the day. It will be the lowest in the morning when the lights first come on (and then, 7.9 or 8.0 is perfectly normal), and the highest when the lights go off. The reasons for this are basic chemistry -- when the lights are on, algae photosynthesizes, which takes up carbon dioxide. When the lights are off, algae don't photosynthesize, they don't take up carbon dioxide, so the carbon dioxide accumulates in the water, carbon dioxide + water = carbonic acid, and the weak acid drops the pH until the lights come on again and the algae take in the carbon dioxide again.

You can avoid pH swings by running a refugium with macroalgae on a light schedule opposite of your display tank lights, so when the display tank lights are off, the macro algae is still photosynthesizing and taking up carbon dioxide.

 

[SigEpLucas]

Thanks Biff, I've been thinking about going with a 10 gallon sump under my tank and just using a HOB overflow box and small submersible pump to run it, would it be pretty beneficial to do this and then use part of the sump as a refugium? And if I did this, is there a cheaper way to light the 10 gal fuge than buying another 200$ light fixture?

 

[Bifferwine]

Oh yeah, if you're growing macroalgae in your fuge, then you don't need any special lights. For my fuge (which is a 35 gallon rubbermade tub), I use two regular old plant bulbs (aka grow bulbs) in a regular old light fixture from Lowe's. I believe the bulbs cost $5 apiece, and the lights cost a total of $8.

Lots of people also use the cheapo fluorescent strip lights that you can find at any pet store. Those will cost maybe $20 or so, for the fixture and bulb.