Yes there is a harder type of algae, it is normally called fleck algae. It appears as small green spots at first which can grow larger over time. At first it looks like regular algae and makes the glass look green. As the algae grows more mature the flecks themselves begin to look like green snowflakes without the starry shape.

It can still be removed, I would buy a new algae scraper first. You are correct they do wear out over time.

i highly recommend olive nerites. i have 8 of them cleaning a 55 gallon planted tank. they don't eat plants, DO eat stubborn algae (like the giant patch of brown algae i originally got them for), and don't reproduce in fresh water. best things i've ever put in my tank.

-ming

Plants do introduce unknowns, like snails. I have never heard of olive nerites but that sounds like a natural approach. Other things can also be done. A good algae scraper is one. Another is to have floating plants that cut down the light below. Another is to have fish that like to eat algae, like mollys and otocynclus cats. You an employ all of these approaches. They are not mutually exclusive.

Here is a link that might be useful: olive nerites link

Hi
The last time I checked there are several thousand named species of algae It is runaway the most common lifeform on earth lol So the answer to your question Yes there are MUCH tougher forms of algae. They range from single cell to tree size size monsters.
I have always found them fascinating particularly the SW water types though the FW fixed types that undulate in the water are downright beautiful IMO lol.
All algae requires is a continuous source of moisture
So any aquarium is going to have algae
I've generally found that the various types spontaneously ,appear during the water cycle which I think goes on almost indefinitely the most noticable the first 6 /10 weeks.
My hat is off to botanists who can tell one species from another . I rely on growth habit.
As your tank gets older you'll notice changes in how the algae grows and how vigorously.
It is possible to maintain aquariums with very low visible algae the most effective is vascular plants to use up the food source. Try all the recommended methods and get a new pad lol. Sooner or later you'll find a variety
that MUST be physicly removed lol.
Have to admire a lifeform that can live on over 99 percent of the earth!! gary

I'd replace your scraper. If it's a glass tank, a metal scraper will work wonders. If it's acrylic though, you're stuck with a gentle scraper. My acrylic 55 gallon tank gets that extra-tough green spot algae--it's SO hard to remove! It seems to get worse when I leave the curtains open in my living room and the tank gets extra sunlight.

Forget the overpriced tank scrubbers sold for aquariums and the next time to pass a dollor store, pick up some plastic pot scrubbers. They will clean the glass effectively without scratching and after use, a dip in bleachy water will clean them completely. Rinse and let dry and they will be perfectly safe for reuse.

For acrylic, try the soft scrubbing pads sold for facials. Same as the ones sold for aquariums, just a heck of a lot cheaper.

Thanks everyone for the information. I have a glass tank, so it should be easier to clean this stubborn algae off. I did buy a new scrubber and will have the chance to try that tomorrow. I looked at a metal (blade) scraper at the local aquarium shop, but shuddered at the price!! I thank you, Birdwidow for the good advice. I think I can probably get a better action using a scrubber by hand rather than trying to manipulate the long plastic handled version. It is good to know, however, that I was on the right track suspecting that I could very well be up against a harder variety of algae. I learn so much coming here!

Anne

Anne,

You are right. It's a lot easier to control the scrubber if you use your hand and not mess with the long handle and for a cheap but equally effective razor scraper, stop into your local home center and buy one of the cheapie plastic jobs sold for scraping paint from windows.

Just be careful when you get near the acrylic sealant inside the tank but for cleaning corners, the Dobbie will do the job nicely. So will one of the green scrubbers sold for cleaning pots and anyone who believes they are any different from the ones sold at over the top prices in pets stores has little understanding of what they are made of.

I paid two dollars for a razor blade paint scraper and use it on my glass planted tank, it works wonders. Its been the best two dollars I spent in a long time.

The side of a credit card works well too.