Water changes in a rift valley setup

[nickmcmechan]

I'm going to do a rift valley and was wondering about pwcs.

I will be using crushed coral and ocean rock to buffer pH

As a result i'm guessing i'll end up with 8pH or so

my tap water sits around 7.0

should the tap water pH be altered before addition since the change in pH would be so big as to shock the fish?

 

[steve p]

I would do frequent small water changes, That way you will keep changes in Ph to a minimum.

Steve

 

[jpappy789]

pH shock is when there is a large difference. Smaller PWC (10-20%) shouldn't dip the pH enough to seriously stress out the fish.

 

[jm1212]

it should be fine if you do a 10%-15%

just stock smart so your nitrates dont go out of control

 

[Coler]

nick my tap water is 7, my Ph in the tank 7.8. I have crushed coral substrate and tufa rock.

When I do a 50% water change, untreated except for Prime, Ph in the tank drops to 7.6 or so. A 25% change leaves it unchanged.

Tank size 180L; I do 25%x2 weekly.

 

[nickmcmechan]

So, sound like pwc more than 25% need to be careful with.

Reason I'm asking is all the advice I've heard so far is not to alter pH using chemical buffers, ws wondering if this should be the case if I want to do a large pwc then?

 

[magakitty]

We've never had a problem, but we also rarely have to do large changes. We usually change only 10 gallons out of 55 at a time. It would probably be better to do several small changes over a period of time if you needed to do a big change

 

[nickmcmechan]

yeah, see your point.

i'm assuming that the consensus os that no one really uses anything to alter the water chemistry them before adding?

 

[Coler]

I think the effect of a large water change will be different on each tank, and its good to know what way your parameters are affected by it, even if you prefer a routine of smaller and more frequent changes; in some situations you may simply have to do an emergency large change. In that situation if your water is chemically buffered from e.g. 7 to 8.2 you might have difficulty balancing the changed water and cause Ph shock.

I go by the principle that it has to be over 7 for a start, up to 8.2 if that's what you can achieve with good buffering, but stable at some point lower than that is better than trying to use the chemicals to increase.

Even when I do a 50% water change it doesn't bother me that my Ph drops by a couple of points.