The answer would be "both". I'm getting them for terrible algae outbreak that is current, along with basic algae maintenance. I had them in the past and they did such a good job.
Tank maintenance and such: We do weekly water changes, have high output lights (3 watts per gallon in one tank and 4wpg in the other), leave the lights on for around 12 hours per day. One tank is stocked pretty heavily, the other pretty light, I feed them twice a day and only what they eat in about 3-5 minutes. That's all I can tell you.
I think I found a good place to get the SAE's - will post later on the results of how they arrived and such.
Well, good luck with the SAE's. If you have an algae problem, they certainly are a good quick fix. You might want to think about a few issues that could help you control the algae without the addition of specialized fish:
1) You don't need to feed your fish everyday, especially not twice a day. Yes, they'll happily gobble up the food but that's mostly due to their innate feeding response and has little to nothing to do with their actual hunger. You might want to consider cutting back on the feedings to at least once a day, every other day.
2) You don't really need 12 hours of light to keep your plants healthy. 9-10 hours should be fine. The longer you keep them on, the more food you're providing for the algae, especially if there's some kind of nutrient imbalance in the tank.
3) Re-examine your stocking levels. You don't mention what you're actually dealing with but you did say that one tank might be a little overstocked. Adding more fish to that tank would be a bad idea. Think about maybe getting another tank for some of the "extras" or upgrading to a larger one. I'd suggest bringing them to the LFS for a trade in (like for more plants) but I know it's a costly trek for you.
But, yeah, it seems like you have some other issues to deal with that, when corrected, might provide you with better results than can be obtained by adding SAE's.
Just my 2 cents. Good luck.
