A couple months ago I finally got my tank connected back up to the basement sump but just before that I was fighting an issue with hair algae. After hooking up the 100 gal sump, skimmer and bio tower the algae all but disappeared in about a week. Well over the last 2 weeks teh hair algae has come back..Part of the problem I know is that my TDS has spiked and is running up near 300. That should be fixed in the a few days with the new RO unit on it's way and should arrive on Monday.
However I don't think it is the whole issue. I've noticed that the algae is even growing in patches on the substrate. After some exploration I found that my sandbed just doesn't have anywhere near the population of worms and pods that it once did and because of that there are lots and lots of dead spots. Since I near replaced the sand when the tank crashed it seems to be loaded with detrius from everything that died in there at the time. So I have decided to siphon out most of the sand and replace it with fresh substrate. I'm going to remove most of the sand on one side of the tank put in the new stuff and wait a couple weeks, then do the same on the other side. I've already removed a bunch of it during 2 large water changes but there is lots more to go.