Much needed help..... Cleaning rock

So I have about 45 lbs or lr in my 55 and I have more arriving on Thursday(dry). I don't know for sure but I think I have red cyano on my rocks along with detritus ect... My question is if I do a good sized water change, use my old water and take rocks out and scrub them then put them back in my tank and put in new SW will I be ok? I don't wanna start a mini cycle I just want my tank clean!! I think I took care of the nutrient problem and I'm getting livestock delivered on thursday and you know how it is, you don't want them comming home to a dirty house. Any advice is greatly appreciated!!

 

No matter WHAT you do as housekeeping, the cyano will return quickly if you don't fix the problem that's causing it. You'll likely hear there from others, but here goes:

It sounds like your tank is new...how long has it been running? Young tanks tend to go thru an "algae cycle" as they settle in (I'm not referring to the diatom bloom). If this is the cause, manual removal should keep it at bay until the tank matures a bit.

If your tank is unpopulated, what's fueling the red cyano? What are your nitrate and phosphate levels?

The detritus buildup suggests that you have insufficient flow in the tank, or at the very least in those areas where the detritus is built up. Modifying the flow pattern or adding additional flow will help here.

If you swish the LR off in SW, it should be OK, but if you scrub it too much, you'll remove some/most of the aerobic bacteria that makes up your biofilter, so you'll likely have some form of mini-cycle or possibly even a larger cycle.

Also, when you add the fish (hopefully not more than a couple of specimens if it's a new setup), you may see a slight cycle...if the tank is well-cycled, generally just a few diatoms.

HTH