A Ph Of 7.6

[Crazy fishes]

I am in need of some advice once more my pH has shot down to 7.6. This is bad news, right? I have tried to correct it with buffer solution (Red sea buff success) of which I have used about 125ml and pH has barely moved. I do however have an alkalinity of 2.9-3.6 milli equivalents per liter. Any ideas why my pH is so low. All other parameters are normal ammonium 0.1 ppm, nitrite 0.025 ppm, Nitrate 10ppm, phosphate is high at 1.5mg/L but this is really strange since phosphate is another buffer ion yet pH=7.6?? It should be higher but is not, WHY?? I am really stuck please help?!!

Regards

 

[SkiFletch]

CO2. Increase surface agitation

 

[CageUK]

CO2. Increase surface agitation

Yes I agree with Ski. My PH was starting off at around 7.7 in the mornings up to 7.9. I first removed my flow diverter from my outlet powerhead which made a difference and last night left my skimmer running along with associated micro bubbles overnight and got this morning up to a ph of just over 8. I have turned the skimmer back off and have put an aerator block in my right hand chamber to try to stablise my PH but cut down on the microbubble until my new skimmer arrives.

Cheers

Mark

 

[Crazy fishes]

Thanks guys most appreciated. I have just noted that my pH is around 8 at the moment. I think it must be related to the change in lighting which has solved my algae problem but lead to the drop in pH. Let's see if I can stabilise it with my new routine.

Cheers again

 

[Crazy fishes]

Me again just an update. I got my water tested again today since the water chemistry is everywhere and have found several rather worrying things. My marine lab is useless and my salt is ...... useless and my water chemistry and filter are all over the place. However the good news is my clown which went a bit funny last night is well again and my phosphate and nitrate are behaving. I found out the reason for my pH troubles is due to my low Kh which was 6 (incidently yesterday it was 7). My pH was 8.0 but the lights had been on for several hours and some rather vigorous surface agitation. The ammonia is on the rise at 0.2 and my nitrite is at 0.025. As I said nitrate is behaving itself at 0 and my phosphate is down by a 1/3 (now 1.0 from 1.5) in just 24 hrs. I had introduced Rowaphos yesterday which explains the reduced phosphate and nitrate. Incidently Rowaphos also explains why my Kh dropped since it took away the phosphate which was helping to prevent my pH crashing further. I am adding carbonate buffer now, the stuff I was supplied with was also useless. The salt, marine lab and buffer solution are all made by RED SEA and has been removed from the market. What I bought was old stock apparently which really sucks because it nearly killed all my live stock. Red sea are releasing a new standardised line which should be hitting the shops at any time but this has been the case for eons....... Hopefully my tank will florish once more

Regards

 

[steelhealr]

You need to give us a VERY IMPORTANT NUMBER here.....the CALCIUM level....one of the biggest players in the buffer system. Bicarb is not great to be adding over time. CALCIUM may be better.....

Number please? SH

 

[Musho3210]

dont rule out faulty test kit, it could have been 8.0 when you thought it was 7.6, and it could be 8.4 when you thought it was 8. What test kit are you using?

 

[SkiFletch]

And are you testing at the same time every day? Especially if your waterflow and surface agitation are marginal you can have bigtime swings in pH (and resulting calcium/alkalinity) due to photosynthesis and respiration in your tank. Were I you I'd be testing both in the morning AND at night

 

[Crazy fishes]

Ok SH I have freshly measured the Calcium today with my kit and the calcium level is supposedly 480ppm. I believe the normal range is 400-450, right? The idea behind buffers is to soak up the excess hydrogen ions which requires negative ions like hydrogen carbonate and carbonate. Calcium is positive and does not interact with positive H+ ions (Likes repel). However calcium is commonly the postive ion that is interacting with carbonate and hydrogen carbonate which explains why all those buffers are full of calcium.
Ski, I said in my previous thread that it is Red sea kit (owned apparently by Interpret) and yes I do measure around the same time every day. Also I did say on several occasions that the kit I am using is for the most part less than useless. The pH and nitrate tests are fine; they are compatible with other readings that I have got from my LFS. The Calcium test is, I believe, ok but never compared that to the LFS measurements.
I am planning to the API test kit and buy singles for the rest which are not included. Incidently which kit do you use??
Just to let you know that everything is looking better in the tank and the algae bloom is well...... unbloomed, GOD BLESS ROWAPHOS !!!!
I am going to wait until the end of the week and look around for some xenia which may help stabilise the water chemistry further.

Thanks for the input guys most appreciated

Regards

 

[Donya]

Just want to throw something out for consideration. CO2 is one possibility, but I did have a problem when I first set up my 12g with my carbonates & calcium getting out of whack and the pH was stubbornly stuck at around 7.8; definitely wasn't an off kit because it checked out with several types. The pH wouldn't go over 8.0 until I got my buffers sorted out and switched from using anything with NaHCO3 to Na2CO3 (the NaHCO3 was acting as a weak acid and was "salting out" as small amounts of CaCO3 due to really high calcium levels).

 

[Colin_T]

sounds to me like everyones tanks are running a bit low on the PH side. Natural seawater on most coral reefs is about 8.4-8.5
I keep my PH stable with sodium bicarbonate, (available from any supermarket for a pitence). Put some in a salt shaker and sprinkle daily until you get to the desired level.

 

[Crazy fishes]

Colin that is the point of this thread; I have a new nano which has cycled and recently got loaded with live stock. This has eaten the buffer and caused my pH to plummet which lead to the thread for help "A pH of 7.6". Recently got some carbonate buffer which is reviving my tank, pH 8.2 and looking to stabilise there !! Carbonate is better in some respects than bicarbonate because the molar ratio for carbonate:hydrogen ion is 1:2 whereas the ratio for bicarbonate is 1:1. This means carbonate will suck up/ buffer twice the H+ ions than bicarbonate. The other benefit is carbonate has a natural pH of around 8 whereas bicarbonate is somewhere around 13. Saying that you would have to load your tank with tons of bicarconate to get a pH of 13.

Regards .

 

[Donya]

The other benefit is carbonate has a natural pH of around 8 whereas bicarbonate is somewhere around 13.

Source please for the carbonate & bicarbonate pH references? Free carbonate ions present in the same amounts as free bicarbonate ions (in different solutions) should produce higher pH values than the bicarbonate ions. I've observed sodium carbonate to easily shoot RO's pH from 7 to over 12, but sodium bicarbonate is not nearly as effective IME.

This means carbonate will suck up/ buffer twice the H+ ions than bicarbonate.

There's the added issue that bicarbonate won't always accept an H+ and prefers to donate one when a stronger base is present.

 

[steelhealr]

The best way to stabilize the system is with kalkwasser or calcium. Bicarb alone can lead to buffering issues with calcium. For our nano systems, a 2 part calcium/bicarb system is probably the best in the short run along with consistent weekly water changes and then running a refugium and lighting it opposite the main tank.

I assume your substrate is aragonite? SH

 

[SkiFletch]

Qute the chemistry quandry we have here. Ok, some lessons:

pH of seawater is a very very complex thing. With so many ions suspended near saturation in the solution and a wide array of equillibrium reactions taking place, a lot can happen very quickly in small, closed, biologically active seawater conditions. Typically as Donya alluded to, pH will be unstable/low if Calcium, Magnesium, and Carbonate/Bicarbonate (alkalinity) are not in balance. To eliminate some confusion here, natural seawater typically has a pH of 8.2, Calcium of ~410ppm, Magnesium of ~1280ppm, and an alkalinity of 8-9dKH. If one or more of your numbers is out of whack, you can easily depress the pH of the system. It is OK if all of the "big three" (calc/alk/mg) are high in proportion to one another (example: 450ppm, 11dKH, 1350ppm) but having one value significantly higher or lower than normal while others differ is bad (say calcium 450, magnesium 1250, alk 7). Make sense?

A pH that low 7.6 I still maintain is either a faulty test kit or a problem with CO2. Its doubtful that the ion/buffer chemistry is so far out of whack to produce that low of a pH. FWIW, I only use salifert test kits.