Kh/ph During Fl Cycle

[190MPH]

While I'm in the midst of my FL cycle(4+wks), I've been doing alot of reading about pH crashes and the relationship to KH. My question is, what is considered a low KH? Mine is about 4-5 dH out of the tap and it had remained steady in the tank. Yesterday, it seems that it dipped a little to about 3. The pH has remained steady at 7.8-8. GH is ~9 dH.

 

[OldMan47]

Compared to mine, you have a low KH at 5 degrees. Mine runs closer to 12. The 5 degrees should be adequate as long as you stay on top of water changes when they are needed. If you let things go too long between water changes, the nitrates will consume the carbonate hardness in the water and the pH will drop.

 

[waterdrop]

For what its worth, my own experience with "what to think of as low KH" went like this: Somewhere around 4dH seemed to be about the turning point. 4dH and above seemed to stick around a while, whereas below 4dH seemed in my case to mean that a KH and pH crash would be coming on pretty fast in the next couple of days. Now in my case the pH was never as high as yours. My tap pH had a high of about 7.6 and it would hang at about 7.2-7.4 in the tank while the KH was staying staying above 4, but then would come crashing down through the 6's once the KH started dropping through 3, 2, 1, zero.

~~waterdrop~~

 

[190MPH]

I will check again tomorrow. If it continues to drop, then this will require another water change during my cycle? If the pH stays where it is, should I let it go for now? I'm hoping this isn't going to slow the cycle anymore.

 

[190MPH]

Its still at about 3dH today, pH still 7.8-8

 

[waterdrop]

If you just write that in your log, you will start to have empirical data on what to expect KH and pH to do (how many days/hours before dropoff) in your particular tank.

~~waterdrop~~

 

[OldMan47]

That set of data that WD suggested will be much more valuable to you than our experiences with KH vs pH. It will tell you what to expect your own water to do in your tank. There is no way we can actually give you that information, it is unique to each tank and each water supply.

 

[190MPH]

Thanks everyone. I am keeping a log of the progression, so I will have a good idea what's going on. I just wanted to get a general idea of what the outcomes and consequences could be.