nearly 1 year Old Tank with lots of Green Algae is this normal?

[Wowraya]

Hi I have a question and hope you can advise.

I have an Opae Ula Tank in our library that was purchased from an educational marine center who did an educational program for us.

We have had the tank for nearly 1 year after several months it developed a thick carpet of algae that covered all surfaces: rocks, fake plants, and the gravel. I recently topped off the tank and a good amount came off of the rocks and the gravel floor.

Is it normal to have this much algae, which the shrimp seem to avoid, they prefer the glass walls. We had one tiny snail but I no longer see him, so perhaps that is why we have too much algae? no snails to eat it.

I recently bought some pipipi snails online and I haven't put them in yet to see if they clean the tank.

I was wondering if I should remove the shrimp to clean the tank or perhaps just try scooping out some of the algae or just put the snails in to see if they clean the tank.

What do you all think? Thank you in advance.

*I've attached so pictures, the tank doesn't look too bad anymore since a lot of algae lifted from my tank after refilling with distilled water.

[tooth]

How much and how often are you feeding?

[Wowraya]

Never fed them and there is no filter.

[KenCotigirl]

Looks like blue green algae. One of my tanks have it. I physically remove it being careful not to through out any shrimp. No idea why it is there but I am having trouble removing it permanently.

[NancyM]

It couldn't hurt to see if the snails will clean it. You can always take them back out if you don't want them in there.

[Mustafa]

Physical removal along with the brackish water snails will do the trick. I haven't had any cyanobacteria (blue-green algae) probably in over 6 years. I have enough snails and never feed too much. The macroalgae may help maintain the lack of cyanobacteria by competing with it for nutrients.