Fishless Cycle pH

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TDWagner

Aquarium Advice Apprentice
Joined
Jan 6, 2006
Messages
28
Location
Indiana
I know there's a ton of fishless cycle threads, but I couldn't find anything about high pH levels during cycle.

From what I've read, pH numbers below a certain value (6.4 or so?) can cause a cycle to stall.

What about high pH? My tap water (after sitting out overnight) is at 7.8, but in my 55G aquarium it's more like 8.6 or 8.7 right now. Does this hurt the cycle?

I have about 4ppm ammonia and no nitrites or nitrates yet.
 
If it makes you feel better, my pH is in the mid 8's.

Although I don't know if that helps you, because I've lost three fish already and I'm afraid it could be related to that.

So I guess that really doesn't make you feel better.

Perhaps someone with a clue will help you. I'm still a supern00b.
 
Yeah, that's why I went fishless cycle....I don't know this kind of stuff. The bacteria is the only thing I need to worry about keeping alive right now. I'm hoping the pH will stabilize after cycling is finished.
 
How long has the tank been set up? When did you add the ammonia? The PH will settle down after you cycle the tank. What is the KH of your tap water?
 
Well, if your tap water has a pH of 7.8, and your tank is over 8, something is raising the pH. I would suspect something in the substrate, such as crushed coral.

Now, the sources I have read state that nitrosomas ideal pH is 7.8 to 8. Yes, pH below 6.5 was bad, but the sources did not discuss if a certain level of alkalinity had the same effect. So, I don't know if a pH of 8.6 is good, bad, or indifferent.

But I would find out what it is in your tank that is raising the pH and eliminate it, your tap pH of 7.8 is OK for fish, thats what I have.
 
while you are cycling you are going to see a lot of pH swings... mine went from really alkaline to really acidic... then stabilized back to slightly alkaline. It will stabilize once the cycle is complete but ammonia and nitrite will effect the pH. I wouldn't worry about it.
 
I set up the tank and added ammonia 10 days ago.

I haven't measured KH.

I'm hoping it's just the ammonia that's messing with the pH. I certainly won't be adding any fish until it's nice and stable.

I'm just trying to decide if it's a good idea to do a PWC to bring the pH back down a little or if that wouldn't really make any difference.

Thanks for the link Tom....I certainly don't want them to grow slower. This fishless cycle is taking too long already!!! It's torture staring at my empty tank every day!! :?
 
Well, I finally got a nitrite reading today, so I'm going to go out on a limb and say that 8.6 pH is safe during fishless cycle. :)
 
Yeah, don't worry about the pH being 8.6, other than I am convinced that there is substrate or rocks in your tank that are rich in calcium carbonate, and that is why your pH went up so much above your tap pH.
 
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