Low Ph in reef tank

[walleyebum]

My ph is around 7.8 and I cant get it up. My tank is 500 gallons and the corals and starting to look bad from this low ph. All my other levels are fine just cant raise the ph up. I have a powerhead facing up to bring more oxygen into the tank and that worked before earlier in the summer but now its not working anymore. And we had our windows closed for awhile due to the heat so the co2 levels are prolly high due to the ac running now.

[heathlindner25]

I have the same pH and my coral, including the acros... look fine
If your ALK is steady,maybe look elsewhere for the problem

[walleyebum]

levels are. salinity 1.025
nitrates 10
phosphate .25
calcium 460
alkalinity 10

[shellsea]

I have had success with kalk drip to increase Ph. Also I have read that an air line from outside connected to skimmer intake line may help.

[heathlindner25]

levels are. salinity 1.025
nitrates 10
phosphate .25
calcium 460
alkalinity 10

Yeah ,but how stable is the system? What type of lighting and filtration? How often do you do water changes , do you vacuum your sand during maintenance, what are you currently dosing and how much do you feed? There's a lot more factors that go into play with " keeping color"....
One last question are those API test kits?

[walleyebum]

Yes api test kits. And my tank is very stable but just recently the ph in staying low. The lighting its 3 ecotechs pro lights, and a 150 gallon or so sump. And water changes every week and I stir up the sand every week. I have kalk drip going since last week and no changes.

[outssider]

3 radions on 500 gal display sounds a bit weak...don't you recon ??

[heathlindner25]

Personally I look at the sand as a filter and I vacuum it every time I do a water change....how many gallons do you change a week? I don't think it's your lighting but what intensity are you running the ecotechs at?
And as far as your test kits, no offense but I wouldn't trust any of those numbers....invest in some high quality low range test kits and get some real numbers we can work with. I hope this helps a little bit.
When you're trying to pin down problems and fine tune "color" you really do need high quality test kits.

[heathlindner25]

3 radions on 500 gal display sounds a bit weak...don't you recon ??

Wow...I didn't catch that, that is a bit under powered....to focused on the API test kits..lol

[walleyebum]

I have the wide angle lens and have great color to the bottom of the tank haha. And the intensity is at 80

[heathlindner25]

Definitely need good test kits to figure anything out... but you have a full tank shot ?

[walleyebum]

:beer:

[heathlindner25]

I'm thinking it might be nutrients

[walleyebum]

Should I just do more water changes, and reduce on feedings? I feed krill in the morning, 2 large pieces of lettuce in the afternoon and pellets for night.

[heathlindner25]

I would start with getting accurate test kits

[BrettDS]

I went through this recently and in my case it turned out to be high CO2 in the house. A quick check is to take a cup of tank water and an air pump outside and let the water aerate outside for an hour, then check the pH. In my case, the pH in the tank was running between about 7.5 and 7.8. After aerating the water outside for an hour the pH went up to 8.2.

I ran a tube to the outside for the my skimmer's air intake and that totally solved the problem for me. The pH in the tank slowly rose over 3 or 4 days and now runs between about 7.9 and 8.3.

So before you spend too much time on this, just take a cup of water outside and aerate it for an hour and see if that makes a difference. I didn't even use an airstone... I just stuck a short airline tube in the cup and let it bubble away.

[BigJohnny]

There are 2 seperate topics here IMO. The cause of your low pH and your corals health.

For pH, as you know it is directly related to co2 and alkalinity. Since your alk is up at 10 it's definitely high co2. Either your water is not aerated (not in equilibrium with your inside air outside of the tank) or you have high co2 in your house. Most likely you have high co2 in your house and therefore the only solutions are:

1. Bring in outside air
2. Run a co2 scrubber
3. Refugium/plants to uptake c02
4. Kalkwasser

Ideally a combination of all of the above. Decaying organics also lower pH but usually this is a cycling tank problem. This will tell you everything you need to know about pH in aquaria:

http://www.reefkeeping.com/issues/2004-09/rhf/

Coral health- need to know more about your tank like mentioned above. There are plenty of tanks that run at pH of 7.8 and look great, so there are likely other factors involved here. Low pH is more likely to affect growth rates than color.

I also agree that most API test kits are unreliable because they are hit or miss. I have had some that match up with high quality test kits, and others that aren't even close. Certainly worth considering. You should also monitor pH periodically so you get a range of what your dealing with. This will also tell you how much your pH swings, which if significant can cause problems regardless of whether it is low or not.