Join Date: Mar 2007
Location: Hendersonville, TN
Nuts! I don't have Photoshop, so I guess I'll have to stick with pictures and the occasional video. Oh well...it was worth asking.
To answer your question: it could be, and likely is, "both." I feed my fish every other day, once, and only as much as they can eat for five to ten minutes. So, if you are feeding multiple times per day, I would cut that to once per day. Many fish in the wild don't eat daily, much less multiple time per day. In addition to any leftovers the snails may be munching on, they also are grazing on the dust algae. Snails do not typically eat hair algae, green spot, or bush algae species unless it is dying or dead, and the same goes for plants. I've never seen a snail eat living plant tissue; rather, they will eat a dead or dying leaf off of a plant, if anything. Nonetheless, they will graze on dust algae. You will have to play with your CO2 (probably increase it), your fertilizer regiment (less ferts less often), and or your lighting (decrease the amount, or the time the lights are on). You may wish to increase your water changes if toying with those three variables doesn't eventually lead to less algae.
On a related note, I have found that most of my tanks go through different algae phases until the tank reaches maturity, which often takes months. Usually, it starts of with dust algae, then goes to hair algae/Chlado, then to Black Beard Algae, then finally to GSA before disappearing (visibly, of course....algae is ALWAYS there, as you know). However, you can limit this by making sure your tank has plenty CO2, decrease the photoperiod and then gradually start adding more time back to it, and decreasing food and/or ferts and then gradually increase the ferts. I don't follow specific fert schedules anymore; they never worked for me, and led to more problems than solutions. I fertilize when needed, and once the tank is mature with plenty of plants, then you can dose with more frequency as there will be enough plant mass to uptake those ferts, thereby leaving less for algae species to utilize.
Just my 2 cents.