Hi all,
Same as the others really, it isn't an issue and it won't deplete the oxygen.
You will need to clean out at some point, but it will probably always have some algae whilst it is receiving enough light. If you wrap a black bin bag around the holes it that should stop it growing.
When we used to use distillation units to make "distilled water" (pure H2O) we used to get a very fine, almost imperceptible fuzz of green algae grow on the translucent aspirators where the water was stored.
When I started working in the lab, I mentioned to the technician (an independently wealthy ex-medical chemist) that there was algae in the distilled water. He explained to me that I was mistaken, and that it was pure H2O and nothing would grow in it. I explained to him that whilst I wasn't an analytical chemist like him I had a degree in Botany and it was definitely algae. This situation went on for about 6 months, with him both refusing to admit it was algae and refusing to let me clean the aspirator.
By that time I'd found that he tried to stop any-one using "his" distilled water, as if they didn't use it, he didn't have to turn on the steam distillation unit (which quickly furred up with scale and then needed regular maintenance). He also kept setting the lab clock 1/2 hour fast, and I'd found out that when I wasn't there he locked the door and refused to answer the phone to stop any-one using the lab. The lab. was referred to as "the morgue" by all the staff, and they all went out of their way not to upset him.
Eventually I just got extremely frustrated with the whole affair and just before the summer break I added a couple of cm3 of the complete plant nutrient "Long Ashton solution" to the aspirator, the nutrient addition was in extremely small, even for N it would have been parts per billion (ppb) . The effect was quite remarkable and a fortnight later the aspirator was bright green with a thick algal pelt on the walls. For some reason soon after that he left.
cheers Darrel
