Limestone

[jamjarjames]

Well as you may remember i posted about what i needed to add to RO water to mak it fish safe and it was determined that all i needed to do was raise the KH oh the water. Well ive been out in the garden and found a load of limestone that ive broken up and put in the tank, the Ph overnight raise from 6.2 to 6.8, my question is however will this keep rising or will remain stationary. Im aiming to keep a Ph of about the 6.8 it is now as im going to be keeping tetras which prefer the water a little acidic. How can i control the Ph with the limetone in it? I really don't want to have to take it out cause it makes the tank look loads better.

Thanks

 

[OrionGirl]

Hard to say--how much impact it has will depend on how quickly the limestone breaks down, which in turn relies on the makeup of the limestone. I'd keep watching it for a few days before making any assumptions.

 

[liv2padl]

there's nothing magic about a pH of 6.8 and i think you'll find that accepting your waters inherant chemistry and utilizing it will result in a far more stable environment than trying to modify it with rocks or chemicals out of a bottle. a change from 6.2-6.8 in 12 hours can be extremely injurious to fish.

the vast majority of fish in the hobby today can acclimate to a wide range of water chemistry, including your ph of 6.2. if it were my tank, i'd leave the pH alone. as for rocks, i'm sure that such decoration does indeed make your tank look better ... why not consider non limestone rocks which will not alter your waters pH and kH.

 

[jamjarjames]

The thing is i need something to raise the KH, i can't have a KH of 0 otherwise i will get huge Ph swings. Limestone adds to the KH value in the water but it also raises Ph, i just want to know if the Ph will keep risisng between water changes and how often i am going to do those changes to keep the Ph in check.

It doesn't matter at the moment about how quick my Ph or any other parameters change because im just about to start fishless cycling and theres nothing in the tank thats gonna be affected

 

[liv2padl]

i just want to know if the Ph will keep risisng between water changes

the pH and kH will rise until an equillibrium is reached. what your ph and kh values will be when that occurs is impossible to predict ... it depends on YOUR inherant water chemistry. once the levels are stable, they should remain that way since you will have elevated your buffer capacity. how often you will need to do water changes is as much predicated on your ultimate stocking density as your water chemistry.

i keep and breed cichlids in 75 gallon tanks .. and do 50 percent or so water changes on a weekly basis.