Yes, mean nasty stuff! The first bucket of water I cleaned out was filthy, loads of crap!
Unless I pull the entire thing off the glass and get other filter/pump/heaters to replace these I'll just have to make sure it's all cleaned out every wc (have to stick gravel cleaner down at the back at an angle and clears out pretty well). But as no problems with this tank for years I'm thinking best to leave it where it is! And just up my maintenance!!
Really think this is the root of the issue, tank's gone well for so long and fish all seem happy. It's almost 9 years old so guess done pretty well so far!
When my Goby's out and about it's normally a good sign 'stuff's' ok, he's quite a sensitive chap and not appearing to bother him at all. Or anyone else.
So definitely won't stress about it now discovered what's prob caused ph issues.
Thanks a lot @Blacktetra
, you've been so brilliant
Tank's not the prettiest, bit of a mess, but tend to plant 'around' the fish! Had cories so long that trashed the place, now snails, so easier to leave areas clear so everyone can get around causing the least damage!
Got my lone Blue Rainbow fry to go in and join his parents and the gang, almost 2months old now and obv grown rather slowly being a Bow but as long as I know no major issues can get in there to cause trouble soon