hi erk628
that is interesting that you don't get algae in the tanks with lots of water movement, or that are heavily filtered. Normally water movement doesn't make a lot of difference to algal growth and it is more dependant on light and nutrients.
Green water will be removed by good filtration but there are plenty of other alga that grow in tanks. You might have stumbled onto something interesting as far as algae control goes
High turn over rates with attempts to get water movement and nutrient delivery to all four corners of the tank is how successful planted tanks are run. The results of a failure to deliver nutrients to all four corners is well known to most people by now. Low nutrients = poor growth = leached ammonia from plants = algae. Nothing new there to most people who know how to run planted tanks.
Good filtartion should be an obvious benefit in the fight against algae. It is an obvoius benefit in most situations in this hobby. Good O2 and no algae is a also a situation that has been speculated, but with no hard evidence. Large, frequent water changes also help, particularly in the early days of a tank.
Plants outcompeting algae for nutrients is a bit of a non starter for me, as once all my plants have taken their necessary nutrients out of the tank, there is still an excess which alga could capitalise on, but doesn`t.
A 13 hour photoperiod is definitely too long and should be reduced to 8 - 10 hours.
I am not trying to jump on any kind of high horse, but from my experiences and observations, most of what has been wriiten on this thread is incorrect. There is even an indirect mention of allelopathy, which is taking the battle against algae back a few years. I have read Diana Walstad`s Ecology of the Planted Aquarium, but that doesn`t mean it exists in our aquariums. There is no proven build up hormones in our tanks that inhibits algae growth. It has been tried between tanks with exactly the same plants, but with a chemical build up permitted in one tank, but still no difference in algae blooming was noticed. In a poorly run tank, all our plants fall foul of algae.
Donna, you can control algae in your tank via light and keeping your plants happy. However, a picture is vital before any specific advice can be given.
Dave.