waterdrop
Enthusiastic "Re-Beginner"
No, you are thinking about your pH thing all wrong. Your pH suddenly dropping now near the end is a "good" thing, in the sense that its a sign your beneficial bacteria are truly beginning to run a bigger nitrogen cycle in your tank! The final product of the cycle, the nitrate(NO3) has a nitric acid component (about 7% or so) when its in water (as it is of course) and this is the acid that goes to work on whatever buffer you have and potentially can use that up and suddenly drive down the pH, stopping the bacteria.Since you -know- you are fishless cycling and you know you have a lot of nitrate(NO3) in there, the plan of choice is to perform a large (90%, meaning down to the substrate) water change (with good technique as usual) and then recharge the ammonia (carefully to 5ppm since you are nearer to the end of your fishless cycle) and your bicarb. You absolutely do not need to be worrying about crushed coral in this situation. (Crushed Coral is just a different method of raising mineral content, just like bicarb, but is the method of choice when you have fish because it is automatically very slow in causing the changes and quick changes will kill fish.)
Being forced to do some big water changes to clear nitrate and to raise pH near the end of a fishless cycle is a good thing in that it gives you practice with the logistics of these types of water changes. They will be possibly the most important maintenance activity after you get fish, There is -nothing- quite like a good gravel-clean-water-change for refreshing the vitality of a freshwater aquarium!
You two (ryefish and Dan) are making me think about my own bogwood, lol. Some of the other regulars like OM47 et.al. have learned that a lot of the fun for me is cerebral rather than coming from as many tanks as I used to have. When it comes to my tank my son and I are running, I'm boringly slow to make major changes. To wit I've had a beautiful piece of bogwood that I've been soaking... since last fall (yes, all winter
) and its still giving off tannins but the truth is it takes a week to give some off and they would easily be handled by weekly water changes, so its long been in good enough shape to go on into the tank and really the other thing I'm stalling about is deciding which java ferns to attach -where- along the bogwood such that I'll end up with a good look to the resulting aquascape - that part is hard for me. I did have a great weekend though in that I successfully transitioned a small group of new neons over from my quarantine tank into the main tank and added yet another group of baby neons to the Q-tank right afterward! This morning they are all alive and well and both groups are accepting tiny moving bits of the high protein flake food they like, which means both groups will likely make it, yea! 
~~waterdrop~~
) and got 0 ammonia and the Ni's are just as awkward with a colouring between 0.25 and 0.50.
