pH crash

[Camescu]

I've got a 23L edge set up, live rock, a peppermint shrimp and a couple of Halloween Hermits.
Recently I've noticed the pH drop from around 8-8.2 down to 7.6. No ill effects on the inhabitants but I can't understand the crash.

Water I buy is 8.2 and the hob filter provides the oxygenation. I've got a reasonable whack of crushed she'll in there too.

Any ideas on the cause?


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[mr_X]

What time of day did you check it? PH usually fluctuates in a 24 hour period.

[Camescu]

8pm. But I've checked at various stages over last few days.

Is a fluctuation from 8.2 to 7.6 normal?


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[Ingy]

What is your alkalanity at? Low Alk can cause increased pH swings.
If all is low you can raise it with baking soda.



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[Camescu]

I'll have to check that later.
Odd thing is I use shop water where parameters are fine, so there has to be something with my set up that is causing it to crash.

Ill give the baking soda a go, but I'd rather understand the problem for the long term.

Any ideas?

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[Sniperhank]

I wouldn't be trusting store water to be fine. Is be testing it as well.


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[Camescu]

Yes. I have been testing store water. That's how I know its fine :p

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[Ingy]

Alkalinity is one of the basic water parameters you should be testing. pH is kinda irreverent, as it does swing throughout the day and night. Alkalinity is also what determines how much or how far the daily pH swings are. Higher Alk means less pH swing. Unfortunately corals absorb that which makes up alk (i.e. carbonates), meaning the pH swings can increase as time goes on.
Having an appropriate pH level (8-12 dKH or about 3-5 meq/l) will bring your pH level up to the range you want (8.2-8.4), so manage the alk and let pH follow on its own.

[Camescu]

I'm fresh out of ideas guys.

Today's test....

Ph: 7:6
Ammonia: 0
Nitrite: 0
Nitrate: 0.5
Alkalinity: 12 (4.3 meq/l)
Salinity: 1.024

I am now a peppermint shrimp less and ph won't budge. Anyone else had a similar problem shifting ph?



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[Sniperhank]

If it stays there it shouldn't be a problem. Though, a fresh thought...besides a hob what is moving water in the tank?

[Camescu]

Small powerhead. Fluval Sea CP1 I think.

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[Camescu]

I'm hoping to add a hectors goby in the near future, if that makes a difference.

Obviously acclimatising would take longer.

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[coralbandit]

Your LR could be consuming the carbonates(kh) as mentioned and causing low pH.
I had to buff my 75 reef at least every week for kH and Ca yet the tank next to it(with cultured{man made} LR) never needed a thing!
try to keep your kh up and the pH should follow.
Do you have a lid(sealed) on tank?
If so that is holding back gas exchange and causing the co2 to rise lowering pH.
Open the lid or look into a screen top if so.

[Sniperhank]

Either way, I don't see a problem. Ph fluctuates through the day and what you've described isn't out of control. Just sounds like the natural swing through your day.

[Camescu]

Originally Posted by coralbandit

Your LR could be consuming the carbonates(kh) as mentioned and causing low pH.
I had to buff my 75 reef at least every week for kH and Ca yet the tank next to it(with cultured{man made} LR) never needed a thing!
try to keep your kh up and the pH should follow.
Do you have a lid(sealed) on tank?
If so that is holding back gas exchange and causing the co2 to rise lowering pH.
Open the lid or look into a screen top if so.

Kh at 12 should be OK though? Maybe a calcium buff needed?
Having said that, its a fluval edge so totally covered. This could be it!

I'll be looking to mod the lid when I can afford to upgrade lighting.

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[Camescu]

Originally Posted by Sniperhank

Either way, I don't see a problem. Ph fluctuates through the day and what you've described isn't out of control. Just sounds like the natural swing through your day.

Cheers. Seems to stay at 7.6 whatever time I test at.

And 7.6 is the lowest reading on my kit (red sea). I just hope it isn't much lower.

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[coralbandit]

The lack of gas exchange is probably your issue.
You could just lower the level alittle to allow more air into tank and see over a couple of days if it helps bfore major re construction.
My 75 went from 12-13 to 6-7 in 1 week for over a year!

[Camescu]

Ta. I'll try that

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[PB_Smith]

Originally Posted by Camescu

I've got a 23L edge set up, live rock, a peppermint shrimp and a couple of Halloween Hermits.
Recently I've noticed the pH drop from around 8-8.2 down to 7.6. No ill effects on the inhabitants but I can't understand the crash.

Water I buy is 8.2 and the hob filter provides the oxygenation. I've got a reasonable whack of crushed she'll in there too.

Any ideas on the cause?


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This caught my eye.
Do you have actual crushed shells or is it crushed coral.
There is a HUGE difference and excessive shell fragments is one suspect in elevated phosphate levels.

If it is actual shell, you should actually remove it if practical and get some form of aragonite rock or sand.
I just picked up some of this, Carib Sea Rubble Zone, chunks of aragonite rock and it's on sale right now;
CaribSea Rubble Zone: Aquarium Substrate

that would help buffer the ph/alk slowly and should help maintain it.

[Ingy]

With a 12 dKH, I'm not surprised that it's difficult to change your pH. That's the thing Alk does, chemically. It stabilizes pH.

How are you raising your Alk? Or is that the level water changes make it?


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