chaeto wont grow

[delo978]

Well I'm running into this situation and have never had this problem before so looking for input. My fuge is approx 5Gallon within a 10G tank and it contain 3" LS, 5lbs or so LR and 3-4 hermits/amphipods/critters. It's got about 5 times flow with a 65K coralife bulb. Now my chaeto just isn't doing anything, hasn't shrunk, discolored, fell apart, GROW, it just sits there. I know it probably requires more flow so it can tumble however I'm not comfortable putting that much flow in my Fuge as it's pretty small. Another problem I thought it could be was I haven't had nitrate in my tank since it cycled so maybe it's not getting the nutrients required. So what are my options?? My DT is a 40G with 15 Zoos frags, frogspawn, hammer, torch, candy canes, blastos, 2 clowns, 1 tang, 1 bi-color blenny, 1 watchmen goby, 1 coral banded shrimp, 1 cleaner shrimp, 1 tube anemone, 1 PLTA, and snails. My parameters have been perfect and steady for a long time. So no ones asks to be more precise here they are.
Salinity - 1.025
Alk - 9dKH
PH - 8.3
Phos - 0
Calcium - 420
Ammonia - 0
Nitrate - 0
I keep a log of my tests and tests every second day and there mostly the same every time except my Cal so I dose that once a week. As far as Chemical filtration I use carbon (which I change 1/month) and purigen. Thanks for any input cause I'm at a lose here. Oh and I use a Remora skimmer and it takes lots of crap out of my tank so it works fine.

Cheers