I'm looking for a good drop checker for my 75g tank. I'm also looking for scaping equipment, like scissors, tweezers, substrate flatener, etc.. My tanks is 20" deep so I'd like them to be kind of long. Thanks.
I have one. People say they're a bit on the delicate side and can break easily, but I've had mine for a couple years with no problems. I'm not sure how long they last. I would guess at least a couple months. Then just replace the solution and stick it back in your tank.
I also have one of the scaping kits linked here. Good stuff. 'Tis why I linked them.