Will removing a large rock from the sand bed cause a nitrate spike?

I have this medium rock, about 9lbs, that takes up about about a quarter of my 30g tank's footprint. It is absolutely covered in halimeda, which have grown to reach the top of the tank; it's cutting light and flow by blocking my powerhead and lights on that side, and it's catching debris in its stems. It's a cluster larger than a basketball.

I've already cut it down to the rock a few times before, but it grows so long and so fast it's a real pain to keep up with. I don't even want to know how much calcium it's stealing from the rest of the tank but it's just exploding, literally inches per day.

Anyway, since it's currently isolated to one rock, I'm thinking of taking it out and letting it all die off, by shoving it in a dark bucket. I'm not terribly concerned about the rock dying off, there's little on it but coralline, since the halimeda has taken it over. What I am concerned about is pulling the rock off the sand and causing a spike or cycle, since it's a small tank. I plan to do some decent water changes before, (in prep) and after, to negate any potential consequences. I'd keep it for a refugium if it didn't suck on calcium. Maybe I can start a planted tank with it.

Any other suggestions?

 

I did this before with one of my GHA rocks, it kicked up some detritus, but I never saw a spike or any weird behaviour from the fish.

 

Well I ended up ripping it all out again, hopefully some the loose pieces that came off won't plant themselves somewhere. If they do I'll just have to nip their growth in the bud.

I'm going to move it all into a 40g breeder soon, just want to figure out what I'm going to do with it until then; it's not making the move until the plant is gone.

 

Put the rock in a bucket of Hydrogen Peroxide for 3 minutes assuming it has no corals on it. Put it back in the tank, the algae will die. If you stir up a enough detritus it can always cause a spike but in this case the dying algae could cause one too. If you have an excellent skimmer though it should be able to mop up the proteins form dead algae. You might want to rinse the H2O2 off with tank water before putting it back in tank.

 

You could also try just spraying the rock with h2o2 and let it sit for 3 minutes. That might be easier.