Changing gravel - advice

[midman]

Hi everyone,

I have just bought some new gravel to replace the rather course 'cotswold stone' type that I currently have. I have bought a finer gravel for my loaches, but I have also realised that my current gravel is keeping the water hard, despite my efforts to reduce the PH and hardness ( the gravel has either lime or carbonate in it). I was undecided about whether to change it in one go or remove half of it because of cycling. My new filter is cycling well now and I have zero Nitrite. I have currently taken out half of the gravel and put this to one end of the tank, putting new gravel at the other end. I really wanted to remove it all so that I can get my GH and KH and acidity down. If I do this, and provided I keep an eye on the nitrite and do water changes if necessary, would this be acceptable

[sophie]

do it slowly.
apart from anything else any sudden adjustment of pH and hardness is going to bother the fish. I'm inclined to think that hardness is actually more of an issue than pH in the long run; but I wouldn't advise anything that's going to involve a sudden drop.

[midman]

Thanks Sophie. My PH is dead on 7 and never changes. I have been slowly reducing the GH and KH so that I can then reduce the acidity slightly, I have been doing this by filtering my water changes. The gravel I had wasn't really up for the job and I am sure is leaching hardness into the water. I have managed to get the GH down from 22 to around 11 now and the KH from around 16 to 8. This has been done over about 4 weeks. As for the PH, now I have the correct gravel, when I reduce the PH it should stop buffering as GH and KH will be lower. I have a measured way to reduce PH in a controlled way and by very small amounts. I am aiming for PH of around 6.6 and GH and KH of around 6. I did change all the gravel in the end and all the levels are still the same. I did do a big water change at the same time and will keep a close eye on all levels, especially nitrite over the next couple of weeks. Thanks again.