Is my gravel going to increase my pH and should I replace it?

[Andrew waterson]

Hi all,

I've just discovered my pea gravel contains a small amount of limestone (or Similar) rock, established with an acid test (using the nitrate solution 1 from API kits).

I'd guess at 2-5% is limestone (based on a few scoops of gravel so a v rough guess) and there's 15kgs in a 160 litre tank, so prob 500-750g in there is limestone.

Is this enough to increase by pH and/or hardness?
I really don't want it any higher (pH is actually about 8-8.2 out of the tap once left to sit for 24hrs) and it is a limit on my stocking choice already

I've got more inert gravel (quartz) on the way (I need a bit more as it's a bit shallow), but would rather avoid the pain of getting out all current stuff out
Also the tank is part cycled (ammonia being cleared and nitrite on the rise) and I like the current gravel!

What do you think?

Thanks

 

[Colin_T]

It will probably increase the pH a bit, but considering the pH is already above 8.0, the small amount of limestone is unlikely to push it much higher. Limestone has a pH around 8.5 so it shouldn't go up much higher than it already is and it will go up pretty slowly so water changes and acids from fish food and waste will probably neutralise it before it does anything.

It is unlikely to raise the GH at all.

 

[seangee]

What's the pH in the tank? That should answer your question, assume where it is now is more or less where it will stay.

 

[Andrew waterson]

It's about 8.2 in the tank and looks near identical to the tap water once it's been left for 24hrs to de-gas.
The tanks been going about a 4-5 days now (using filter media from another tank).
It doesn't seem to have changed, other than after the 1st day.
I thought this was the gravel then found out about the tap water co2 thing and the tap wster has a higher pH

Thanks Colin, that is a relief
This fish keeping business can be stressful!!