Hi any idea why the pH even with 30% weekly water changes keeps dropping ,just done another change and the Ph is showing about 5 ,all other levels are great ,fish seem happy 4 Loaches, 10 guppies 6 swordtails 4 female fighters 4 catfish . Tank is 200 L . Added some crushed shell as suggested by animates. The filter is a fluval 204 just wondering if i should change the filter media. I have some driftwodd in there but its not new and untill a couple of weeks ago the pH was stable .Tap water pH is about 7.I am using tap water to fill the tank

My main tank is fine with a stable pH and no more fish losses .

Thanks :lol:

try feeding the fish less as less food equals less waste which is acid

run a bucket of tap water, test pH. test pH 24hrs later.. check for any difference.

There is something crazy acidic in there. pH of 5 is crazy.

It could be the wood, or something in the gravel etc (any peat?) I'd start by removing the wood but its possible something else is going on in there.

I agree with what Luke posted, test a bucket of tap water 24 hours later and post up the results. This will give us an idea of how hard/soft your water really is, but there has to be something in that tank.

Interesting question, Gill. I've just discovered my main tank has a pH of 6.0 despite my tap water being 7.6 or something crazy. The only thing I can think of is the driftwood in the tank, even though it has been in there for many years so I would have thought any effect it had on the water would be reduced by now.

You say you have other tanks that you fill with the same tap water, but only this one has the low pH... by a process of elimination can you work out what the difference is between the different tanks...

substrate?

decor?

filter media?

any additives (plant ferts etc)?

I will be interested to know what results you get.

Animates tested the water and the pH is ok , so once again different readings from home tests .But i will re test the water in the bucket tomorrow.I am planning on having a move around as at the moment i have a mixture of fish in there and i want something different .I want to keep the clown loaches and cat fish , there are some of those black widows swordtails , male guppies .i have another big(380l ) community tank so i can move things around. I like the look of gouramis. I am a beginner so i dont want anything to challenging to keep .

The big tank is full of community fish ,my guppies are taking over!!!!!I leave the fry in there now and so far plenty are surviving .

8)

Please take care to acclimatise if you are moving fish between tanks with very different pH levels. I had an unfortunate loss of a male betta - almost certainly a direct result of moving him to a tank with a crazy high pH. I acclimatised him over a couple of hours but it obviously wasn't enough.

should only change them 0.2 of a degree in pH every 24 hrs.. bummer

re tested the water in the bucket it was still 7, pH in tank is 6 so its looking like its stablised now.

thanks for all the info 8)