For the past four weeks or so, I've been fishless cycling my 10 gallon tank. We started out with fake plants on a black sand substrate but have since upgraded all of the fake plants to real ones to include two Anubias and two Val plants. Everything was progressing smoothly and I was waiting on my last bit of nitrites to convert. This past weekend, we purchased two small Amazon Swords to put in the tank and happened to pick up a Betta to put in a 5 gallon we had also been cycling. As it happens, we screwed up the water in the 5 gallon (accidentally used Stability instead of Prime to condition the water). I didn't want to put the Betta in the 5 gallon so instead added it to the 10 gallon tank that was pretty much ready to go. Before we added it, I did two 50% water changes back to back to lower the nitrate level which was at about 40 ppm. I added the swords after the water change, and a couple of root tabs. Up to this point, the water has always been pristine and no algae growth at all. The Vals have been growing pretty well with both plants throwing out two or three runners with small upshoots on each. The Anubias have been opening new leaves but slowly. I added the Betta after acclimation and did NOT feed it that it day. This was Sunday (five days ago). The next day (Monday) I feed it two Betta pellets which it did not eat right away. I figured it was still a bit stressed or a picky eater, it would take a pellet in and then spit it right back out. I left those two small pellets in the tank (in hindsight maybe I should have pulled them out?) On Tuesday I noticed a white cloud of cotton on the bottom of the tank. I thought maybe one of the pellets had just dissolved so I sucked it out of the tank. I did not try and feed the Betta on Tuesday thinking that if it got hungry enough it would eat on Wednesday. On Wednesday I fed two pellets. One of which was eaten over a period of about ten minutes. The other was left alone. I removed this other pellet. That is about the time I noticed all the Algae that had grown on the Anubias leaves. Also, another, larger white cloudball of whispy strands (almost like a spider egg sac) was in the middle of the tank on the sand. This was easy to remove with a turkey baster. Questions: What, all of a sudden, caused the algae growth? Light timer has been the same and tank has been pristine for a bit over four weeks. Added the Betta, two swords and two root tabs (only things that have changed). What is the white cloud of cotton that started showing up randomly? What is the best way to deal with the algae assuming we keep the Betta in the 10 gallon tank?