How deep is the substrate? You can always give it a stir/prod a couple of times a week, I used to keep one of those wooden kebab skewers by my tank for the job (make sure you don't spear any of your fish!)
Free for postage- hagen master test kit (old and dusty)
The one in the case. Don't get all excited, I know it goes for about ?50 brand new but it's old and I think most of the tests have had it and a couple of the test tubes are missing. So it's basically just the case with the spaces to put the tests, hence me not bothering to Ebay it.
Let me know if you're interested and I'll check how much postage is. Alternatively you could pick it up if you're near Cambridgeshire, I'm just off the A1 south of Peterborough.
I made a DIY spray bar once out of a bit of syphon tube. As long as it doesn't slow the flow too much then it should be OK. Which way is the outlet pointing? Just changing the direction a bit might help.
Depends what you've got With ones that have a stem with leaves coming off it (like elodea, water wisteria etc) then you can trim it off wherever you like and if you want you can stick the cutting in the substrate and it should grow a new plant.
If it's got long leaves like vallis then the leaf will die off if you cut it, but new ones will grow from the base.
I had onion plants when I had goldfish and they are pretty tough. They do grow enormous though so if your tank is less than 200 litres then you might want to go for something else. Anubias is small but tough, I had some luck with java fern too.