Stabalizing Ph

[smithyif]

evening all i was just wondering whats the best way to stabilize the PH has mine keeps dropping , tap PH is 7.6 and when i do water tests in my tank the PH is down to 6.0 or below the reason i say or below is the test kit (api liquid) only goes down to 6 , Please help and advise

 

[DrRob]

Main thing is to take a look at what's in the tank that's causing it. Lots of organics in an old tank will do this and some people deliberately do it with peat, leaves or wood, depending on the fish that they keep.
 
Sometimes good sized lumps of wood can have this effect.
 
Heavily planted tanks with small water changes can go this way over time too because of the organic build up.

 

[smithyif]

all thats in the tanks is a [piece of bog wood approx size 8" X 1 1/2 " the plants are all plastic and so are the ornaments , the tank size is 200ltr