Weighing that plant down

You can use things like plant weight or ceramic rings that sometimes comes with plants.

Failing that, simply use a nice piece of wood or rock to weigh down th line at a strategic place and even get the bubbles to come up behind the wood / rock to add a feature if you like.

Have not used fishing lead weight before and unsure if would be all that safe to add to aquarium but probably ok though I’d research or find out first to be 100% certain before using fishing weight.

 

If you mean like a cable tie sort of thing, should be ok to use as I have used that in the past for holding down plants.

And having rocks with holes is handy for threading the airline through to keep that down

 

Well, there is some concerns about what rocks to use in aquaria and limestone is one of those which may be of concern.

This actually kind of depends on your tank set up and livestock.

If you have hard water fish such as Rift Lake chichlids then would be of little concern, in fact limestones and corals are more of a benefit in this case.

In cases of very soft water (anything below 6.0ph) then limestone is a definite no as this will surely have an effect on most soft water livestock.

Limestone is a soft stone like most calcareous stones, such as Texas Holey rocks, sandstone and corals. These can crumble in water over time and can increase the ph of aquarium water.

There is a basic simple test that you can do to see if your stones or rocks may be suitable, one is to do a vinegar test, a couple of drops of this on clean, dry stone or rock and if there is a effect such as fizzing or bubbling then this would not be suitable.

But vinegar is a soft acid really. To be undoubtedly sure, you can use muratic acid, much more powerful and will certainly be a better test the stones or rocks for suitability. Again just a drop or two on clean, dry rock / stone surface and if any affects, don’t use it.

You must note that muratic acid is very strong and protective gloves must be worn when carrying out this kind of test and ensure to rinse everything off thoroughly afterwards.