Brown stuff on glass after adding Kalkwasser??

[disccollector]

Hi everyone,
My name is David and I'm new to this board and have 75 Gallon reef tank with about 100 lbs of live rock. The tank is 8 years old and I purchased it from a friend just last month.
Everything in the tank looked fine until I added a gallon of RO/DI water with 2 teaspoons of settled Kalkwasser and the next morning my live rock and sand bed were coated with, what I think, is brown algae but I'm not sure.
My PH before adding the Kalkwasser was 7.7 and after adding it jumped to 8.4...I used an IV drip but the drip was rather fast in hindsight.
Could the quick jump in PH have caused this? Is there any quick way to get rid of it? I gently raked the top of the sand bed to get rid of it but it comes back the next day.
I purchased some snails and crabs to do some cleaning but wondered if there was a way to kill it by adjusting PH again.
Thanks for any help in advance.

 

[bdhough]

Count yourself lucky you didn't loose any fish? With a ph swing like that..... Keep in mind ph,alkalinity,and calcium are all related.

 

[thomas712]

Wow, you are lucky. As I was told by Bang and Kip you need to drip this stuff slowly, just enough to keep up with the evaporation. Too much to fast will give you a big ph swing. Normal ph of kalk mix is 12 to 12.4 ph, you sure don't want to dump this in to quick. Kip told me to take it slow and start with 1 teaspoon per gallon, then he and Bang said you can bump that up to 2 teaspoons per gallon if necessary.
Call it lesson learned.
Now go back and retry and win one for the Kipster ha SAM
Thomas

 

[disccollector]

Thanks to everyone for their help...I will definitely be more careful next time.
For the person that asked about the brown stuff consistency...it's just like a coating that is powdery...king of like cinnamon sprinkled on toast and heavier in different areas of the tank. Nothing slimey or stringy.
The snails appear to be eating it though but there isn't enough of them to handle all of it. Guess I should get more?