Ok my ph in my old tank went off the high ph scale, which ends at 8.8, so my fish are pretty much sitting in bleach lol. I finally concluded that this was because of the crushed coral, but I just set up my 125 gallon, tested the ph and its the same deal. There is no coral in this tank. A piece of driftwood, fake plants, some rocks and two pieces of decor. I tested my tap water multiple times and it has said 7 each time. I do a water change and the ph drops a little from the new water and is back up again in a few days.

I'm stumped. My fish have thrived with this ph but I would still like to get it down to at least 8. And I know the ph bouncing around isn't good for the fish either.
I plan to add driftwood but I would like to find the source of this spike too.

Wdat is the temp of your water? Do you have a bubbler? Low temps and a lot of surface agitation (high oxygen) will raise your ph. Also what is the substrate in the new tank? Do you have any rocks in the tank. Certain types of rocks will raise your ph too

Yes I have rocks, but they weren't in the old tank, and it did the same thing.

No bubbler, and not a whole lot of surface agitation (normal amount)

Temperature is a little low (76-77) because I refuse to use a heater for fear that it will fry my fish when it malfunctions.

The substrate is just little pebbles.

I noticed the PH in my tank was a bit high too, not sure if it was as high as yours, I had a lot of aeration as well, but i cut the aerator and removed the rain tubes and just had it directly pumping in, and i did a water change the other nite, havent re-checked ph though, ill try and to a check tonight and let you know if the water change and less aeration has lowered it.

i have my tank run around 28C

Obviously something in your tank is altering your PH. It must be the rocks.

Take one out and pour some vinegar on it and leave it a while and see if there is a reaction. Or even better sulphuric acid will tell u immediately. Remember and wash the stone thoroughly

Your diftwood matererial will lower ur PH, not raise it Tony.

Capt Dave wrote:


Ok that's new to me, but indeed my Ph is at 8.
My tank is 75o and has an enormous amount of air and surface agitation, but it's constant...so i do not mess with that

I dont want to be contradictive but temperature and aeroation wont affect your PH that much, if any.
Its the material in the tank that is doing it. Just a bit of detective work that is needed.

JamieM wrote:


I would remove all from the tank except fish and water and start from here. substrates do affect PH and its my guess rocks and substrate are the problem. start with a clean base tank, fish ,water, pumps, heater. thats it. leave it like that for a number of wks and you will notice the PH settle down. if you like you can add the bog wood too, but this will have a little affect in dropping the PH, as this is your goal there is no reason not to add the wood.

I have added some wood trying to lower the ph. But I just haven't added enough to have any effect.

can you describe your pebbles and rocks..... i they are from coral materials,
they will indeed increase your pH... some driftwood could help lower it gradually

marcus wrote:


X2

You will probably find it is either the rocks or substrate rasing the Ph