Help with low PH

[Myra123]

I woke up this morning and noticed that something was wrong with some of the corals in my tank. Even after half an hour of the lights being on an encrusting grass type coral wouldn't open. I also saw a bristle star out in the open. IMO sure signs of a problem.

basic info-- 90 gallon with 75 gallon sump

Parameters

PH -7.7 (was 8.0 the day before)

No nitrates, phosphates

Kh- 9

Ca- 420( i think its ppm)

My question is what would have caused the sudden drop in Ph? The day before just happened to be when I decided to do testing.

I didn't dose Ca in the past two weeks b/c my Kh and calcium were good.

My test kits are new except for Ph but I've been using that one lately and it seems to have been working and showing normal results.

Is there a good website that I can just learn the chemistry and stop guessing?

 

Gmubeach told me to dose a ca/ph upper slowly but I don't get why with a solid Kh and Ca in the tank I should have a low Ph?

Anyhow, I did what he told me and the the thing wavy coral thing has started to come out.

Thanks for any suggestions...esp if you want to give me a chemistry lesson

Myra

[Chad]

Welcome to WAMAS!!

 

IMO, Randy Holmes-Farley is a great starting point for reef chemistry research (he is really good about citing sources so if you really want to dig, there are a ton of references to ferret through). RC has a link to a bunch of the articles here. I am not going to pretend to be as versed as he is, so I will just post his links Here is a low pH article that can be found with the previous link.

 

And, since I am channeling Randy at the moment, from the article:

 

The first step in solving a low pH problem is to determine why it exists in the first place. Some possibilities include:

1. 1. A calcium carbonate/carbon dioxide reactor (CaCO3/CO2 reactor) is in use on the aquarium.
   2. The aquarium has low alkalinity.
   3. The aquarium has more CO2 in it than the surrounding air due to inadequate aeration. Don't be fooled into thinking that an aquarium must have adequate aeration because its water is very turbulent. Equilibrating carbon dioxide is MUCH harder than simply providing adequate oxygen. There would be NO change in the pH between day and night if equilibration of carbon dioxide were perfect. Since most aquaria have lower pH during the night, they also are demonstrating less than complete aeration.
   4. The aquarium has excess CO2 in it because the air in the home that it is being equilibrated with contains excess CO2.
   5. The aquarium is still cycling, and has excess acid being produced from the nitrogen cycle and degradation of organics to CO2.

[Origami]

First, do you trust your pH measurement? How are you testing it?

 

Multiple things can cause low pH. Excess CO2 from a high ambient level is most common. High respiration (instead of photosynthesis) and low gas exchange is another possibility. It could also be a build up of organic acids from decomposition or an incomplete nitrogen cycle.

 

Considering each in reverse order:

 

How old is the tank? Have you checked your ammonia levels? Is any livestock missing? What is your feeding regimen like? Have you had a food spill? Is your skimmer working?

 

Have you changed your light cycle in the last few days (a lot of darkness coupled with low gas exchange from poor surface agitation can raise CO2 levels in the tank). Is there good surface agitation that promotes gas exchange?

 

Have you changed the ambient air conditions recently? Perhaps sealed up the house (closed windows)? If you take a water sample outside and aerate it for 20 minutes using an air pump and an airstone, does the pH go up significantly?

 

Any other changes in the tank? What temperature are you running at? (Temperature can affect gas solubility. The lower the temperature, the more soluble most gasses are in water. More CO2 = lower pH.)

[OldReefer]

I have been struggling with my pH as well. I think it is because of the weather. CO2 levels go up when the house is closed up. My skimmer is in the basement and I can't get to outside air. As an alternative, I tapped into a nearby AC duct and ran the skimmer return to that. My pH has been going up about 0.05 per day since. I am up to 7.95.

[Myra123]

Great articles Chad. I am trying now to learn all of the factors but I think that turning the AC on full time might have been the major factor. I've made some changes and things are slowly moving up. I also took some water to the LFS and had them check the Ph and it was still a bit low.

Again thanks for the suggestions of things to look at.

[DaveS]

What time the day before did you measure the ph? If it was after the lights were on for a while that could explain it. A drop in ph from 8.0 to 7.7 overnight when the lights are out is not unheard of.

[OldReefer]

I'll bet your pH is back up again after the weather cooled and you opened the windows. Mine went from 7.0 to 8.1.

 

I am going to find a way to pull outside air into my skimmer somehow.

[OldReefer]

Typo I meant to say 7.9 to 8.1

[BowieReefer84]

I fight low PH as well and have used Seachem marine buffer with good results. http://www.seachem.c...rineBuffer.html

 

Doesn't fix the source of the problem, but seems to help myself when needed.

 

Here is a good article http://www.seachem.com/Library/Articles/Marine_Water_pH_Control.pdf Obviously they are pitching their product, so take it with a grain of salt.

Edited June 8, 2010 by BowieReefer84

[Coral Hind]

I'll bet your pH is back up again after the weather cooled and you opened the windows. Mine went from 7.0 to 8.1.

 

I am going to find a way to pull outside air into my skimmer somehow.

 

Yeah, my pH was perfect last night with all the windows open. Over .2 higher then the weeks before with the windows closed and the AC on. Getting fresh air into the house makes a huge difference.

[Myra123]

[/media]Thanks again for all of your responses.

In response to the air/ light on or off variable I think that they are both not factors. In one of the link on PH there was a test in which you place some of the tank water with bubbler in house and check ph and then new water and place outside and check ph to determine O2 saturation as the problem. I did this test and found that it was not a O2 problem. I thought that was a great way to check that.

 

Anyhow, Ph is back to 8.0 but really hasn't been a concern for me since I had the impeller on my skimmer and the main intank pump break in just a few days, so ph has taken a back seat.

[/media]

Note the incredible amount of algae that has taken hold since the skimmer shut down. But all in all things are still not dying yet...now to go and spend lots of money online, on new equip. This is of course right after I ordered new LED bulbs last week. When it rains it pours.

Edited June 16, 2010 by Myra123

[Origami]

Water changes can help cut back on the build up of bad stuff, Myra. You may have to lean on that until you get your skimmer operational again.

 

If the impeller was beginning to fail earlier, it may have played into the drop in pH. As mentioned in my original post, build up of organics can cause a pH drop. If your skimmer was on the verge of failure, skimmate production may have been down and the organic acid build up on the rise. This would cause a pH drop.

 

What kind of pumps are you running (the ones that have failed, that is)?

[gmubeach]

Tank looks good though I've never seen pictures! Hope you can fix the issue... stop buy and get some water ok:)