pH going crazy

[Helios]

I've had my 65 gallon up and running for about 2 months now. Everything cycled great and the fish were doing well until about 2 weeks ago when my fish started dying. Everything is normal except for my pH. It is super super high. Like 8.8. I took a sample into the lfs and they came back with the same thing. I use conditioned tap water in the tank, and all of my tanks without problem. The lfs tried to tell me that is because I'm using tap water that it's so high and the pH of the tap in my area is that high so I need to buy RO water from them. I checked the pH of the tap when I got home and it was only 7.2. What could be in my tank that's causing this?

Stuff in my tank:
Substrate pool filter sand
3 large pieces of drift wood
Large rocks from when I had a salt tank (no idea what type of rocks they are)
Several live plants

Could it be the rocks?

 

[bigsea]

It could be the rocks. I know limestone raises ph or any porous rock that contains high calcium carbonate and some macro algaes will raise ph. Try boiling the rocks and doing a decent sized water change. If that doesnt help id leave the rocks out


- St Charles Almendras Geraldizo

 

[Fresh2o]

Yes, it could be the rocks. If you could remove one, place it in a bucket or container filled with tap water and let it sit overnight. Also set aside some tap water in a separate container with no rocks as a control. Test the pH in the morning. If it is high then it's the rocks.
You could also remove a rock and drip some vinegar on it and see if it fizzes. If it does then IMO it does not belong in a FW tank.
If you suspect it is the rocks then you may want to remove them at this time.


Sent from my iPhone using Aquarium Advice

 

[Helios]

Thanks. I pulled all the rock and did a 50% water change. I got it down to 7.4. I think I'm going to just leave it out. It's really porous and white. I don't have this issue with any of my other fresh tanks and the only thing this had in it that those don't was the white rock. I'll try the vinager thing and see what happens. We'll see what the pH is tomorrow morning.

 

[bigsea]

Im sure youll be good. Glad things worked out for you


- St Charles Almendras Geraldizo

 

[Mebbid]

The rock used in salt water aquariums is called live rock which is a calcium based rock generally made out of dead coral. One of the properties it has is that it will break down to increase the pH of the water.

 

[gilpi]

I'd have to go with the rocks from the SW tank as well, I would just leave them out.

 

[Helios]

Didn't work. I pulled all the rock. Did a 50% water change got the pH down to 7.4. It's back up to 8.0 today! What the heck could be going on?

 

[bigsea]

But it WAS 8.8 correct? Its possible the rocks leached out. Keep watching it and do nice deep gravel cleaning. It should go down man i dunno what else it could be


- St Charles Almendras Geraldizo

 

[Helios]

The new guess, and this is something I haven't tested until today when I brought another sample to a different lfs, my alkalinity is through the roof. Higher then what their test kit could measure. They had no ideas about why or how to fix it. Any ideas here? I don't even know what alkalinity is but they are thinking is driving my pH issue.

 

[KevinB]

The rock will raise the alkalinity significantly along with the pH.

My guess is that the rock still shed lots of small debris that is still continuing to disassociate and raise the pH alkalinity with time. If you can't find it, and vacuum it out, you may need to do a substrate change. If small, with enough water changes it should dissipate. Good luck.

 

[coralbandit]

The new guess, and this is something I haven't tested until today when I brought another sample to a different lfs, my alkalinity is through the roof. Higher then what their test kit could measure. They had no ideas about why or how to fix it. Any ideas here? I don't even know what alkalinity is but they are thinking is driving my pH issue.

Alkalinity is KH(carbonate Hardness).
It is what buffs and holds pH stable....
It is still in the tank from the rocks...
Many vacuums and water changes should help...
As for the reading being too high to be read , the reading is how many drops to change color?Maybe too high for them to count(like over 10???)

Next take a sample of your tap water and set it a side for 24 hours and then test pH.
This is your real pH (probably not 7.2 after outgassing)....

 

[Helios]

Okay. I'll keep vacuuming and doing water changes. Hhow frequently and how large of changes can I do safely?

 

[enrgizerbunny]

You've removed the rocks which our best guess were calcium carbonate.

Pretty much the carbonate molecule is in the water and it wants to keep the water around it a certain pH, and the concentration of carbonate determines the overall pH assuming it's the only driving factor(8.8 in your case). You change water and add water of a lower pH, but the carbonate is still in the water that remained, so it sill raises the pH of the water around it, but there's less carbonate now so the concentration is lower and the overall pH it stops at 8 instead of 8.8.

I'd be doing smaller frequent water changes, like 25% daily or every other day. pH is something that your fish are very good at adapting to, but terrible at handling sudden changes of.

The small water changes will take longer, but will show down the change in pH. Doing large changes to lower pH will be changing it quickly, which stresses the fish far more than sitting in water with a pH of 8 that is stable.

Sent from my SCH-I435 using Aquarium Advice mobile app

 

[bigsea]

You've removed the rocks which our best guess were calcium carbonate.

Pretty much the carbonate molecule is in the water and it wants to keep the water around it a certain pH, and the concentration of carbonate determines the overall pH assuming it's the only driving factor(8.8 in your case). You change water and add water of a lower pH, but the carbonate is still in the water that remained, so it sill raises the pH of the water around it, but there's less carbonate now so the concentration is lower and the overall pH it stops at 8 instead of 8.8.

I'd be doing smaller frequent water changes, like 25% daily or every other day. pH is something that your fish are very good at adapting to, but terrible at handling sudden changes of.

The small water changes will take longer, but will show down the change in pH. Doing large changes to lower pH will be changing it quickly, which stresses the fish far more than sitting in water with a pH of 8 that is stable.

Sent from my SCH-I435 using Aquarium Advice mobile app

+1


- St Charles Almendras Geraldizo

 

[Helios]

Okay. Thanks all. I'll keep doing small changes.