Ph Question

[amf17]

I've had my tank up and running for about 6 months.... when i first started the ph of my tap water was about 7.6.

After the water had been aged in my tank though... the ph would buffer steady at about 7.8

So today i checked my tank ph... all was fine.... reading of 7.8

But then i checked the tap water.... reading of 7.0

So when i do water changes i'm adding water at ph 7.0 to existing tank water ph 7.8

If i'm doing weekly water changes of about 50%, will this harm my fish or will they be able to cope with a slight change in ph for a couple days until it rebuffers

 

[rocknurworld2006]

your doing far too big water changes every week it should only be 20-30% weekly!
do you have something in the tank that is rebuffing the tank?

 

[Tolak]

Are you using test strips, or liquid test reagents? What is the water hardness, and what sort of substrate & rocks are in the tank?

I change 50% weekly on most all of my tanks, some get more, or more frequent water changes. Lowering the pH is one method used to get some species to spawn, not knowing what species you are keeping makes it uncertain if this applies to your tank.

I would try a smaller water change to start, and check the pH in a couple of days. If it comes up there is something in your tank that is bringing the pH up, or your test gear is innaccurate. If your tap water more closely matches your tank water you can do as large a water change as you like.

 

[amf17]

I'm keeping tetras, platy's and mollies (all the mollies are in another tank right now though)

I don't know what the hardness is because I don't have a test for that...

I do have some crushed coral in the system to keep my ph stable and i assume that's what is bringing my ph up to 7.8...

I have a piece of lava rock as well,and my subsrate is just small pebbles/gravel

 

[rabbut]

With you adding coral to the filters, to buffer the water, it may be an idea to reduce the ammount of water changes in one time, and spread the changes throughout the week. This will reduce swings. The fish in there would be OK with the kind of swing a 50% change would caurse, but they still won't appreciate it (possible with the exception of the tetras? Tolak?).

All the best
Rabbut

 

[rocknurworld2006]

I'm keeping tetras, platy's and mollies (all the mollies are in another tank right now though)

I don't know what the hardness is because I don't have a test for that...

I do have some crushed coral in the system to keep my ph stable and i assume that's what is bringing my ph up to 7.8...

I have a piece of lava rock as well,and my subsrate is just small pebbles/gravel

ypu basically have just answered your question, you dont need anything in a tank to keep ph stable unless you need it at a certain ph!