Fish-Less Cycling - High Ph?

[Bigman]

Hi everyone, 
 
Well, my fishless cycling is well on track (says he with fingers crossed) thanks to all the advice given on this forum.... A full dose of Ammonia is going to zero in under 24 hours and the nitrite produced going to zero in just under 2 days.... so not long to go before stocking with fish whoopee .
 
All plants have settled down now and almost doubled in size! apart from the floating duckweed, that all died off for some reason? Anyway, my problem is that my PH has gone up to 8,2, which is way too high for the fish that I'm planning to get - ideally I want a PH of between 7.0 and 7.5.
 
I appreciate that at the end of cycling, I will need to do a major water change which will bring down the PH to that of my tap water or there abouts, but why has the PH gone up? Am I doing something wrong?
 
If the PH was to rise when I have stocked up with fish, how do I reduce it or keep it at the required level?.....
 
Thanks
Tony

 

[fluttermoth]

Most likely cause is your substrate. Get two glass jars, fill them with tap water and add some of your substrate to one of them. Leave for a couple of days and then test them both and see if they differ.
 
It's very difficult to reduce high pH, as it's normally related to the hardness of the water; unless you remove the minerals from the water (through an RO unit, for instance), any pH reducing products will work for only a short time, then the pH will jump back up and swings in pH are very bad for fish.

 

[TwoTankAmin]

I would like to offer a modification to flutter's suggestion.
 
It is very common for tap water to have either a deficiency or surplus of co2 in it when it comes out. Either one is self correcting once the water goes from the tap to the tank. What happens is co2 will in or out gas relative to the tank to reach an equilibrium with the air. But, if you test the pH before this process completes, it changes the water pH and thus your test reading.
 
Here is the way you can test your tap pH and know the reading is accurate. Take a container of tap water and do one of two things. Let it sit over night+ before you test it or else put an airstone/airline into it and let if bubble an hour, then test it. That way you will know you have a good baseline reading. It may be that your water comes out in balance and the pH doesn't change. But you don't know. I would do this test before doing what flutter suggested as it may turn out your tap really is pH 8.2.
 
If your tap is not pH 8.2. Then do the test flutter suggested to see if this is the culprit in raising your tap pH. However, because you will know the tap pH for sure, you need only do one jar. Either the pH in it rises above your tap or it doesn't.
 
Lowering pH is complicated as noted. I do it in two tanks.

 

[Bigman]

Hi, fluttermoth,
 
Thanks for the advice, I didn't give the substrate a thought.....
I'll test that as you suggest...
 
Cheers

Hi TwoTankAmin
 
Brilliant. I fully understand what you are getting at. and thank you once again.....
 
I'll update this post in a couple of days with the results.
 
Regards
Tony

 

[fluttermoth]

Good thinking, TTA! I'd forgotten about that 

 

[Bigman]

Hi TwoTanksAmin and fluttermoth,
 
Just been thinking about what you said about the co2 in the tap water etc, I'm using co2 (yeast and sugar method) in the tank to help with the plants..... would this be the problem?
 
PS   Tap water on shelf ready to test tomorrow

 
Regards
Tony

 

[Bigman]

Hi TwoTanksAmin, fluttermoth and everyone else
 
Tested the tap water this morning after leaving it overnight as suggested and guess what?  8.2 Ph
So my tank is ok..... whoopee.
 
Now I have a slightly different issue of lowering the Ph in my tank to 7.5 and keeping it there.... any suggestions?
 
Regards
Tony

 

[TwoTankAmin]

Changing pH is a very slippery slope and not easy to accomplish in a stable manner. I kept fish for about 20 years before I was even willing to try. The reason is changing one's pH and holding at the new level in a stable fashion is a complex. if it were just pH, it would be easy.
 
KH is intmately involved as this is what keeps one's pH stable. Rather than try to write it all up here in a post i will direct you to a site which explains it pretty well:
 
Go here http/fins.actwin.com/aquariafaq.html then click on "Your First Aquarium", then click on Practical Freshwater Chemistry and read.
 
 
BTA- CO2 acts to lower one's pH.