light spectrum, plants turning red, and hair algae

[Obsidian]

Okay... here is my latest dilemma:

I have two 15 watt tubes over my 25 gallon tank. One is daylight spectrum and one is a plant spectrum (more bluish). I put the plant spectrum tube in a few weeks ago in place of one of the daylight tubes.

Recently, my plants have started taking on a reddish tinge, in particular, the sword plant and the tips of the hornwort. Also, hair algae... that brown stuff... has begun to grow on older plant leaves. I know that the algae is a result of the increase in blue light. But what about the plants turning red?

Ah... tank is 25 gal tall, eclipse hood, standard eclipse mechanical filtration.... with an empty filter cartridge with occasional ammonia chips thrown in. (in other words, no carbon) DIY CO2 reactor, line-fed directly into an aqua clear power head. Medium pea gravel supplemented with substrate tabs, chelated iron added weekly

89.5 ppm GH (10 dGH)
6.6 pH
no detectable ammonia or nitrate

 

[Harlock]

What kind of swords? Some swords are supposed to put out reddish growth. Ozelot swords come to mind. I see you're adding iron... I think some of the red plants like iron and it helps with the coloration.

 

[Obsidian]

I don't know what kind of sword it is... just big and green. Radicans swordplant, maybe. When I got it, it was very tall with long thick stems and bright green leaves. Now, as I have gradually cut it all back, it is shorter but more intensely green. But this last leaf has reddish veins.

On the other hand, the cryp that I have is a deep red/brown and seems very happy. It did occur to me that maybe this is the way the plants are supposed to look under really good conditions.

 

[Blinky]

I've got a sword (E. blehri I believe) with green leaves and red veins. It's normal, don't worry - I was a little freaked out when mine started growing in this way, but asked here on AC and did some online research - it's just the way some of them grow