Adjusting PH

I cant get my pH any lower than 7.8 (tap water is 7.4) without doing a 75% water change which is something I'd rather not do too often so I've been googling the problem and basically its the gravel which  is topping my substrate. I bought it in an aquarium shop so it's the proper stuff but I shan't use it in my next tank

My options are:

swap the gravel for sand (dunno how I'd do this with fish in there)
use dried alder cones (1 per 1L of tank water, not sure where I'd get them though)
use peat balls from Tyneside Aquatics ebay shop
use sera super peat granules
use Tetra blackwater

AND/OR ( my favorite option) you wonderful people come up with a solution for me. Waterlife pH buffer liquid is NOT an option cos I've tried it and my fish tank turned into a snow globe and I don't know who was more shocked at the time, me or the fish!   

I changed all my tanks from gravel to sand and wouldn't go back. I did the 125 litre when I moved it across the room, that was easier as I had to completely empty the tank to move it. I did the 60 litre I had then and the betta's tank by doing as Colin suggests, though I managed it in one go as I didn't have a thick layer of gravel with not having any plants rooted in it.

Current tank has a 1-2 inch soil substrate under a 1 inch UK gravel topper which slopes to the back of the tank and aquatic fertilizer balls under the plants, which are really well rooted in and going nowhere.

Thankee peeps awaiting help

mmm - that really complicates the matter 'cos no matter what you do your substrate will bring the pH back up again, so I can only see two options....

1) Remove the gravel. The only way I can think of doing this with your set up would be to lower the water level until the fish have just enough to stay upright in and gently lift as much gravel out as you can by hand and replace with pre-washed sand. Then put the water back in. The filter will remove your suspended solids quite quickly.

2) Leave it. There's lots of 'discussion' around the web and techie articles which say that pH isn't as important as water hardness as far as the fish are concerned, and the best thing for pH is that it's stable - so don't futz with it.

Sorry not to be more help.... I've only had one coffee this morning, so give me a while and a few more coffees and I might come up with something else

Choose fish that suit the pH you have rather than the other way round.

Ooops too late I already have the fish

I'm replacing tap water with de-ionised water during water changes now on a 50/50 basis but doing it slowly so the fish have a chance to get used to it, eventually I'll be using 100%, I'm assuming this is the right way to do it?

Since you won't be doing 100% water changes, if you use 50:50 DI:tapwater every single time, this will slowly get your hardness down to the level in the mix of new water then keep it there.
The problem with using 100% DI is that you have to add minerals back in, and make sure you get the same amount at every water change. That means checking all the new water whereas mixing it 50:50 with tapwater is much easier to measure.

Yes, there are testers. I had the API one till it expired. It comes in a pack with a KH tester. They work differently form other testers. You don't add x drops, wait 5 mins and compare to a chart. You add the drops one at a time, shaking after each addition, until the colour changes. The number of drops need to make the colour change = the hardness in german degrees.

Filtered water is not a good idea. If you mean a Brita jug or similar brand, I know from testing the water that it lowers both GH and KH (and it drops my KH to zero) and it drops pH off the bottom of the scale, that is somewhere below 6.0.
Those water softeners that you plumb into your water supply can cause more problems. The Brita jugs swap calcium ions for hydrogen ions, and that is why the pH drops as the higher the number of hydrogen ions, the lower the pH. Some types of water softener swap calcium for sodium, and it is not a good idea to use sodium rich water in fish tanks. I'm sure you aren't supposed to drink this water either which is why this type must have a bypass tap.

Does it say on the pack exactly what the process is for the filtration system is? Filtration does sound different from softener. But I do know that brita style units can be fitted to the mains. If it's that type I wouldn't use those either. If it is this I am not sure what to make of it other than thinking  at the price 



As a matter of interest, do you know why water that has a lot of calcium, and maybe some magnesium as well, is called hard water? It is because it is hard to get soap to lather. Swapping the calcium for sodium makes it easier for soap to lather. I wonder why they used the word 'soft' for the opposite to hard rather than 'easy'. Maybe the term 'easy water' just didn't sound right