i have just recently noticed red slime algee and over night it has gotten worse i tried siphoning the sand i did a big water change... well 10 gal. in a 120gal. tank i changed my phospate sponge is there anything esle i should try ......there is a octo in the tank can this harm him all my levels are good amonia 0 so and so on my protien skimmer is working the foam is pretty clear though

Well, 10 gallons in a 120 gallon tank isn't exactly a big water change!
A 20 percent water change would be 24 gallons or so.

You can remove the red slime manually, by peeling or scrubbing it off rocks and siphoning it off the sand. Have you heard of the recommendation to tie a toothbrush to the end of your siphon, so you can scrub and siphon at the same time? Some of the conditions that promote red slime are poor water quality, high nutrients and poor circulation.

Nancy

In addition to what Nancy recommended...you might want to check your silicate levels also...that red stuff is Nasty!!!

yeah i will change more water but i change 10gal. every weekend and the phospate sponge i used said it removed silicate so... by nutrients do u mean like left over crab parts or somthing else cause i do get all the crab parts i see ....my circulation i have a 950gph pump and a 230gph powerhead... single over flow... should i step that up it seems to move the water very well