carbon source dosing in conjuction with the use of an ATS???

[Floyd R Turbo]

How did your rocks get soaked with P? Did you have have all of that in you 90 before it cracked, running 2x SM100s? For several years?

[SantaMonica]

I added both N and P

[Floyd R Turbo]

Why?

[SantaMonica]

Testing of course. Same reason I raised the temp to 92 F.

[herring_fish]

N and P can get too low for the scrubber to work if you dose too much carbon. This happened to me when I dosed vodka for a short time. Right away my scrubber stopped growing anything. I didn't have anything else for filtration. I have an ATS only tank. I ran for years without any algae growing anywhere, green or coralline. I had a lot of live rock so the high levels of bacteria continued to lower my nutrients without the vodka and without water changes. I fed a LOT but he N stayed low all the time. Eventually, P crept higher and higher until I had to used Phosban.

I looked around the net and found a thread with some guys that where dosing N to bring the Redfield ratio into alinement. I tried it and my algae started growing again.

So....

The bottom line that I am trying to get at is, keep a close eye on the N and don't let it get too low. Otherwise CUT WAY BACK on the carbon! Perhaps the Floyd's idea will mitigate this problem. Just be careful and as always in this hobby ...go slow. A little at a time. Work up to what every you want to do when it comes to any nutrients.