So the conclusion on algae is...?

[MdngtRain]

I don't know what I did, but in the lay week, I suddenly have both green and brown algae and hair algae in both tanks. The only thing that recently changed was the sword plant being split and I put a piece in my gourami tank. Oh, and 1 fish was added to the gourami tank, 6 to the live-bearer tank (juvi platys).
My lighting is the same time length, the temps are the same in the live-bearer tank (the gourami tank had a broken heater that was just replaced recently). Ok, so the gourami tank had a lot of changes, but the live-bearer hasn't... I have plans to get more otos (because I heard they do better in groups), but nothing else into the gourami tank... I hadn't had any luck with snails, and I don't want to take away any food from my pleco fry... But the other tank needs help. Short of snails, what critters can I use to keep the algae in check? Well the otos be enough?
I do about 50% water changes weekly, with nitrites and ammonia at about 0 and nitrates at under 10pp m.... (yes, I only have strips, so I don't know exact numbers, just the range given on the color chart... Insert admonishments here)... The tanks have been going for over 6 months, with the live-bearer at just about a year. I moved 2 months ago, but set up the tanks once here, so the bacteria count kept the cycle going...
Did I miss any info?
Thanks!

 

[OrangeCones]

How old are the lights? Their plant growing effectiveness gets less as they age. Are your lights on a timer? You may want to decrease the photo period by an hour a day and see if that helps keep the algae in check.

Those of us with liquid test kits don't know exact numbers either...still a 'well, more than 5 but less than 10, lets call it 8' guessing game!

 

[MdngtRain]

The lights are relatively new. The gourami tank light is about 2 weeks old, and the bulb on the other tank is only about 5 months old...
I will try cutting the time back by an hour. Thanks.

 

[OrangeCones]

The newer light in the gourami tank could explain the increase in algae there, especially if the old bulb changed out was older (a year + old).

If light/carbon source/other nutrients get out of balance, algae will fill the gap left by what the plants can't use. By giving the tank 'good' night, it may have been too much light for the available carbon/other nutrients. Cutting back a bit on the photoperiod may bring things back in balance and they (plants) may be able to use a longe period again soon, as they take over from the algae.